Add files using upload-large-folder tool
Browse filesThis view is limited to 50 files because it contains too many changes.
See raw diff
- llmeval-env/lib/python3.10/site-packages/jinja2-3.1.4.dist-info/entry_points.txt +3 -0
- llmeval-env/lib/python3.10/site-packages/sympy/__init__.py +535 -0
- llmeval-env/lib/python3.10/site-packages/sympy/abc.py +111 -0
- llmeval-env/lib/python3.10/site-packages/sympy/conftest.py +74 -0
- llmeval-env/lib/python3.10/site-packages/sympy/galgebra.py +1 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/hydrogen.py +265 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/__init__.py +66 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/body.py +611 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/functions.py +779 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/joint.py +2163 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/jointsmethod.py +279 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/kane.py +741 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/lagrange.py +477 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/linearize.py +443 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/method.py +39 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/models.py +230 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/particle.py +281 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/rigidbody.py +366 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/system.py +445 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/__pycache__/test_joint.cpython-310.pyc +0 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/__pycache__/test_lagrange2.cpython-310.pyc +0 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/__pycache__/test_models.cpython-310.pyc +0 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/__pycache__/test_particle.cpython-310.pyc +0 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/__pycache__/test_system.cpython-310.pyc +0 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_joint.py +1144 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_jointsmethod.py +212 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_kane4.py +115 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_lagrange2.py +46 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_method.py +5 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_models.py +117 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_system.py +245 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/sho.py +95 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/__init__.py +0 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/__pycache__/__init__.cpython-310.pyc +0 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/__pycache__/test_clebsch_gordan.cpython-310.pyc +0 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/__pycache__/test_hydrogen.cpython-310.pyc +0 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/__pycache__/test_paulialgebra.cpython-310.pyc +0 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/__pycache__/test_physics_matrices.cpython-310.pyc +0 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/__pycache__/test_pring.cpython-310.pyc +0 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/__pycache__/test_qho_1d.cpython-310.pyc +0 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/__pycache__/test_secondquant.cpython-310.pyc +0 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/__pycache__/test_sho.cpython-310.pyc +0 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/test_clebsch_gordan.py +191 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/test_hydrogen.py +126 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/test_paulialgebra.py +57 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/test_physics_matrices.py +84 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/test_pring.py +41 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/test_qho_1d.py +50 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/test_secondquant.py +1280 -0
- llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/test_sho.py +21 -0
llmeval-env/lib/python3.10/site-packages/jinja2-3.1.4.dist-info/entry_points.txt
ADDED
@@ -0,0 +1,3 @@
|
|
|
|
|
|
|
|
|
1 |
+
[babel.extractors]
|
2 |
+
jinja2=jinja2.ext:babel_extract[i18n]
|
3 |
+
|
llmeval-env/lib/python3.10/site-packages/sympy/__init__.py
ADDED
@@ -0,0 +1,535 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
"""
|
2 |
+
SymPy is a Python library for symbolic mathematics. It aims to become a
|
3 |
+
full-featured computer algebra system (CAS) while keeping the code as simple
|
4 |
+
as possible in order to be comprehensible and easily extensible. SymPy is
|
5 |
+
written entirely in Python. It depends on mpmath, and other external libraries
|
6 |
+
may be optionally for things like plotting support.
|
7 |
+
|
8 |
+
See the webpage for more information and documentation:
|
9 |
+
|
10 |
+
https://sympy.org
|
11 |
+
|
12 |
+
"""
|
13 |
+
|
14 |
+
|
15 |
+
import sys
|
16 |
+
if sys.version_info < (3, 8):
|
17 |
+
raise ImportError("Python version 3.8 or above is required for SymPy.")
|
18 |
+
del sys
|
19 |
+
|
20 |
+
|
21 |
+
try:
|
22 |
+
import mpmath
|
23 |
+
except ImportError:
|
24 |
+
raise ImportError("SymPy now depends on mpmath as an external library. "
|
25 |
+
"See https://docs.sympy.org/latest/install.html#mpmath for more information.")
|
26 |
+
|
27 |
+
del mpmath
|
28 |
+
|
29 |
+
from sympy.release import __version__
|
30 |
+
from sympy.core.cache import lazy_function
|
31 |
+
|
32 |
+
if 'dev' in __version__:
|
33 |
+
def enable_warnings():
|
34 |
+
import warnings
|
35 |
+
warnings.filterwarnings('default', '.*', DeprecationWarning, module='sympy.*')
|
36 |
+
del warnings
|
37 |
+
enable_warnings()
|
38 |
+
del enable_warnings
|
39 |
+
|
40 |
+
|
41 |
+
def __sympy_debug():
|
42 |
+
# helper function so we don't import os globally
|
43 |
+
import os
|
44 |
+
debug_str = os.getenv('SYMPY_DEBUG', 'False')
|
45 |
+
if debug_str in ('True', 'False'):
|
46 |
+
return eval(debug_str)
|
47 |
+
else:
|
48 |
+
raise RuntimeError("unrecognized value for SYMPY_DEBUG: %s" %
|
49 |
+
debug_str)
|
50 |
+
SYMPY_DEBUG = __sympy_debug() # type: bool
|
51 |
+
|
52 |
+
from .core import (sympify, SympifyError, cacheit, Basic, Atom,
|
53 |
+
preorder_traversal, S, Expr, AtomicExpr, UnevaluatedExpr, Symbol,
|
54 |
+
Wild, Dummy, symbols, var, Number, Float, Rational, Integer,
|
55 |
+
NumberSymbol, RealNumber, igcd, ilcm, seterr, E, I, nan, oo, pi, zoo,
|
56 |
+
AlgebraicNumber, comp, mod_inverse, Pow, integer_nthroot, integer_log,
|
57 |
+
Mul, prod, Add, Mod, Rel, Eq, Ne, Lt, Le, Gt, Ge, Equality,
|
58 |
+
GreaterThan, LessThan, Unequality, StrictGreaterThan, StrictLessThan,
|
59 |
+
vectorize, Lambda, WildFunction, Derivative, diff, FunctionClass,
|
60 |
+
Function, Subs, expand, PoleError, count_ops, expand_mul, expand_log,
|
61 |
+
expand_func, expand_trig, expand_complex, expand_multinomial, nfloat,
|
62 |
+
expand_power_base, expand_power_exp, arity, PrecisionExhausted, N,
|
63 |
+
evalf, Tuple, Dict, gcd_terms, factor_terms, factor_nc, evaluate,
|
64 |
+
Catalan, EulerGamma, GoldenRatio, TribonacciConstant, bottom_up, use,
|
65 |
+
postorder_traversal, default_sort_key, ordered)
|
66 |
+
|
67 |
+
from .logic import (to_cnf, to_dnf, to_nnf, And, Or, Not, Xor, Nand, Nor,
|
68 |
+
Implies, Equivalent, ITE, POSform, SOPform, simplify_logic, bool_map,
|
69 |
+
true, false, satisfiable)
|
70 |
+
|
71 |
+
from .assumptions import (AppliedPredicate, Predicate, AssumptionsContext,
|
72 |
+
assuming, Q, ask, register_handler, remove_handler, refine)
|
73 |
+
|
74 |
+
from .polys import (Poly, PurePoly, poly_from_expr, parallel_poly_from_expr,
|
75 |
+
degree, total_degree, degree_list, LC, LM, LT, pdiv, prem, pquo,
|
76 |
+
pexquo, div, rem, quo, exquo, half_gcdex, gcdex, invert,
|
77 |
+
subresultants, resultant, discriminant, cofactors, gcd_list, gcd,
|
78 |
+
lcm_list, lcm, terms_gcd, trunc, monic, content, primitive, compose,
|
79 |
+
decompose, sturm, gff_list, gff, sqf_norm, sqf_part, sqf_list, sqf,
|
80 |
+
factor_list, factor, intervals, refine_root, count_roots, real_roots,
|
81 |
+
nroots, ground_roots, nth_power_roots_poly, cancel, reduced, groebner,
|
82 |
+
is_zero_dimensional, GroebnerBasis, poly, symmetrize, horner,
|
83 |
+
interpolate, rational_interpolate, viete, together,
|
84 |
+
BasePolynomialError, ExactQuotientFailed, PolynomialDivisionFailed,
|
85 |
+
OperationNotSupported, HeuristicGCDFailed, HomomorphismFailed,
|
86 |
+
IsomorphismFailed, ExtraneousFactors, EvaluationFailed,
|
87 |
+
RefinementFailed, CoercionFailed, NotInvertible, NotReversible,
|
88 |
+
NotAlgebraic, DomainError, PolynomialError, UnificationFailed,
|
89 |
+
GeneratorsError, GeneratorsNeeded, ComputationFailed,
|
90 |
+
UnivariatePolynomialError, MultivariatePolynomialError,
|
91 |
+
PolificationFailed, OptionError, FlagError, minpoly,
|
92 |
+
minimal_polynomial, primitive_element, field_isomorphism,
|
93 |
+
to_number_field, isolate, round_two, prime_decomp, prime_valuation,
|
94 |
+
galois_group, itermonomials, Monomial, lex, grlex,
|
95 |
+
grevlex, ilex, igrlex, igrevlex, CRootOf, rootof, RootOf,
|
96 |
+
ComplexRootOf, RootSum, roots, Domain, FiniteField, IntegerRing,
|
97 |
+
RationalField, RealField, ComplexField, PythonFiniteField,
|
98 |
+
GMPYFiniteField, PythonIntegerRing, GMPYIntegerRing, PythonRational,
|
99 |
+
GMPYRationalField, AlgebraicField, PolynomialRing, FractionField,
|
100 |
+
ExpressionDomain, FF_python, FF_gmpy, ZZ_python, ZZ_gmpy, QQ_python,
|
101 |
+
QQ_gmpy, GF, FF, ZZ, QQ, ZZ_I, QQ_I, RR, CC, EX, EXRAW,
|
102 |
+
construct_domain, swinnerton_dyer_poly, cyclotomic_poly,
|
103 |
+
symmetric_poly, random_poly, interpolating_poly, jacobi_poly,
|
104 |
+
chebyshevt_poly, chebyshevu_poly, hermite_poly, hermite_prob_poly,
|
105 |
+
legendre_poly, laguerre_poly, apart, apart_list, assemble_partfrac_list,
|
106 |
+
Options, ring, xring, vring, sring, field, xfield, vfield, sfield)
|
107 |
+
|
108 |
+
from .series import (Order, O, limit, Limit, gruntz, series, approximants,
|
109 |
+
residue, EmptySequence, SeqPer, SeqFormula, sequence, SeqAdd, SeqMul,
|
110 |
+
fourier_series, fps, difference_delta, limit_seq)
|
111 |
+
|
112 |
+
from .functions import (factorial, factorial2, rf, ff, binomial,
|
113 |
+
RisingFactorial, FallingFactorial, subfactorial, carmichael,
|
114 |
+
fibonacci, lucas, motzkin, tribonacci, harmonic, bernoulli, bell, euler,
|
115 |
+
catalan, genocchi, andre, partition, sqrt, root, Min, Max, Id,
|
116 |
+
real_root, Rem, cbrt, re, im, sign, Abs, conjugate, arg, polar_lift,
|
117 |
+
periodic_argument, unbranched_argument, principal_branch, transpose,
|
118 |
+
adjoint, polarify, unpolarify, sin, cos, tan, sec, csc, cot, sinc,
|
119 |
+
asin, acos, atan, asec, acsc, acot, atan2, exp_polar, exp, ln, log,
|
120 |
+
LambertW, sinh, cosh, tanh, coth, sech, csch, asinh, acosh, atanh,
|
121 |
+
acoth, asech, acsch, floor, ceiling, frac, Piecewise, piecewise_fold,
|
122 |
+
piecewise_exclusive, erf, erfc, erfi, erf2, erfinv, erfcinv, erf2inv,
|
123 |
+
Ei, expint, E1, li, Li, Si, Ci, Shi, Chi, fresnels, fresnelc, gamma,
|
124 |
+
lowergamma, uppergamma, polygamma, loggamma, digamma, trigamma,
|
125 |
+
multigamma, dirichlet_eta, zeta, lerchphi, polylog, stieltjes, Eijk,
|
126 |
+
LeviCivita, KroneckerDelta, SingularityFunction, DiracDelta, Heaviside,
|
127 |
+
bspline_basis, bspline_basis_set, interpolating_spline, besselj,
|
128 |
+
bessely, besseli, besselk, hankel1, hankel2, jn, yn, jn_zeros, hn1,
|
129 |
+
hn2, airyai, airybi, airyaiprime, airybiprime, marcumq, hyper,
|
130 |
+
meijerg, appellf1, legendre, assoc_legendre, hermite, hermite_prob,
|
131 |
+
chebyshevt, chebyshevu, chebyshevu_root, chebyshevt_root, laguerre,
|
132 |
+
assoc_laguerre, gegenbauer, jacobi, jacobi_normalized, Ynm, Ynm_c,
|
133 |
+
Znm, elliptic_k, elliptic_f, elliptic_e, elliptic_pi, beta, mathieus,
|
134 |
+
mathieuc, mathieusprime, mathieucprime, riemann_xi, betainc, betainc_regularized)
|
135 |
+
|
136 |
+
from .ntheory import (nextprime, prevprime, prime, primepi, primerange,
|
137 |
+
randprime, Sieve, sieve, primorial, cycle_length, composite,
|
138 |
+
compositepi, isprime, divisors, proper_divisors, factorint,
|
139 |
+
multiplicity, perfect_power, pollard_pm1, pollard_rho, primefactors,
|
140 |
+
totient, trailing, divisor_count, proper_divisor_count, divisor_sigma,
|
141 |
+
factorrat, reduced_totient, primenu, primeomega,
|
142 |
+
mersenne_prime_exponent, is_perfect, is_mersenne_prime, is_abundant,
|
143 |
+
is_deficient, is_amicable, abundance, npartitions, is_primitive_root,
|
144 |
+
is_quad_residue, legendre_symbol, jacobi_symbol, n_order, sqrt_mod,
|
145 |
+
quadratic_residues, primitive_root, nthroot_mod, is_nthpow_residue,
|
146 |
+
sqrt_mod_iter, mobius, discrete_log, quadratic_congruence,
|
147 |
+
binomial_coefficients, binomial_coefficients_list,
|
148 |
+
multinomial_coefficients, continued_fraction_periodic,
|
149 |
+
continued_fraction_iterator, continued_fraction_reduce,
|
150 |
+
continued_fraction_convergents, continued_fraction, egyptian_fraction)
|
151 |
+
|
152 |
+
from .concrete import product, Product, summation, Sum
|
153 |
+
|
154 |
+
from .discrete import (fft, ifft, ntt, intt, fwht, ifwht, mobius_transform,
|
155 |
+
inverse_mobius_transform, convolution, covering_product,
|
156 |
+
intersecting_product)
|
157 |
+
|
158 |
+
from .simplify import (simplify, hypersimp, hypersimilar, logcombine,
|
159 |
+
separatevars, posify, besselsimp, kroneckersimp, signsimp,
|
160 |
+
nsimplify, FU, fu, sqrtdenest, cse, epath, EPath, hyperexpand,
|
161 |
+
collect, rcollect, radsimp, collect_const, fraction, numer, denom,
|
162 |
+
trigsimp, exptrigsimp, powsimp, powdenest, combsimp, gammasimp,
|
163 |
+
ratsimp, ratsimpmodprime)
|
164 |
+
|
165 |
+
from .sets import (Set, Interval, Union, EmptySet, FiniteSet, ProductSet,
|
166 |
+
Intersection, DisjointUnion, imageset, Complement, SymmetricDifference, ImageSet,
|
167 |
+
Range, ComplexRegion, Complexes, Reals, Contains, ConditionSet, Ordinal,
|
168 |
+
OmegaPower, ord0, PowerSet, Naturals, Naturals0, UniversalSet,
|
169 |
+
Integers, Rationals)
|
170 |
+
|
171 |
+
from .solvers import (solve, solve_linear_system, solve_linear_system_LU,
|
172 |
+
solve_undetermined_coeffs, nsolve, solve_linear, checksol, det_quick,
|
173 |
+
inv_quick, check_assumptions, failing_assumptions, diophantine,
|
174 |
+
rsolve, rsolve_poly, rsolve_ratio, rsolve_hyper, checkodesol,
|
175 |
+
classify_ode, dsolve, homogeneous_order, solve_poly_system,
|
176 |
+
solve_triangulated, pde_separate, pde_separate_add, pde_separate_mul,
|
177 |
+
pdsolve, classify_pde, checkpdesol, ode_order, reduce_inequalities,
|
178 |
+
reduce_abs_inequality, reduce_abs_inequalities, solve_poly_inequality,
|
179 |
+
solve_rational_inequalities, solve_univariate_inequality, decompogen,
|
180 |
+
solveset, linsolve, linear_eq_to_matrix, nonlinsolve, substitution)
|
181 |
+
|
182 |
+
from .matrices import (ShapeError, NonSquareMatrixError, GramSchmidt,
|
183 |
+
casoratian, diag, eye, hessian, jordan_cell, list2numpy, matrix2numpy,
|
184 |
+
matrix_multiply_elementwise, ones, randMatrix, rot_axis1, rot_axis2,
|
185 |
+
rot_axis3, symarray, wronskian, zeros, MutableDenseMatrix,
|
186 |
+
DeferredVector, MatrixBase, Matrix, MutableMatrix,
|
187 |
+
MutableSparseMatrix, banded, ImmutableDenseMatrix,
|
188 |
+
ImmutableSparseMatrix, ImmutableMatrix, SparseMatrix, MatrixSlice,
|
189 |
+
BlockDiagMatrix, BlockMatrix, FunctionMatrix, Identity, Inverse,
|
190 |
+
MatAdd, MatMul, MatPow, MatrixExpr, MatrixSymbol, Trace, Transpose,
|
191 |
+
ZeroMatrix, OneMatrix, blockcut, block_collapse, matrix_symbols,
|
192 |
+
Adjoint, hadamard_product, HadamardProduct, HadamardPower,
|
193 |
+
Determinant, det, diagonalize_vector, DiagMatrix, DiagonalMatrix,
|
194 |
+
DiagonalOf, trace, DotProduct, kronecker_product, KroneckerProduct,
|
195 |
+
PermutationMatrix, MatrixPermute, Permanent, per, rot_ccw_axis1,
|
196 |
+
rot_ccw_axis2, rot_ccw_axis3, rot_givens)
|
197 |
+
|
198 |
+
from .geometry import (Point, Point2D, Point3D, Line, Ray, Segment, Line2D,
|
199 |
+
Segment2D, Ray2D, Line3D, Segment3D, Ray3D, Plane, Ellipse, Circle,
|
200 |
+
Polygon, RegularPolygon, Triangle, rad, deg, are_similar, centroid,
|
201 |
+
convex_hull, idiff, intersection, closest_points, farthest_points,
|
202 |
+
GeometryError, Curve, Parabola)
|
203 |
+
|
204 |
+
from .utilities import (flatten, group, take, subsets, variations,
|
205 |
+
numbered_symbols, cartes, capture, dict_merge, prefixes, postfixes,
|
206 |
+
sift, topological_sort, unflatten, has_dups, has_variety, reshape,
|
207 |
+
rotations, filldedent, lambdify,
|
208 |
+
threaded, xthreaded, public, memoize_property, timed)
|
209 |
+
|
210 |
+
from .integrals import (integrate, Integral, line_integrate, mellin_transform,
|
211 |
+
inverse_mellin_transform, MellinTransform, InverseMellinTransform,
|
212 |
+
laplace_transform, inverse_laplace_transform, LaplaceTransform,
|
213 |
+
InverseLaplaceTransform, fourier_transform, inverse_fourier_transform,
|
214 |
+
FourierTransform, InverseFourierTransform, sine_transform,
|
215 |
+
inverse_sine_transform, SineTransform, InverseSineTransform,
|
216 |
+
cosine_transform, inverse_cosine_transform, CosineTransform,
|
217 |
+
InverseCosineTransform, hankel_transform, inverse_hankel_transform,
|
218 |
+
HankelTransform, InverseHankelTransform, singularityintegrate)
|
219 |
+
|
220 |
+
from .tensor import (IndexedBase, Idx, Indexed, get_contraction_structure,
|
221 |
+
get_indices, shape, MutableDenseNDimArray, ImmutableDenseNDimArray,
|
222 |
+
MutableSparseNDimArray, ImmutableSparseNDimArray, NDimArray,
|
223 |
+
tensorproduct, tensorcontraction, tensordiagonal, derive_by_array,
|
224 |
+
permutedims, Array, DenseNDimArray, SparseNDimArray)
|
225 |
+
|
226 |
+
from .parsing import parse_expr
|
227 |
+
|
228 |
+
from .calculus import (euler_equations, singularities, is_increasing,
|
229 |
+
is_strictly_increasing, is_decreasing, is_strictly_decreasing,
|
230 |
+
is_monotonic, finite_diff_weights, apply_finite_diff,
|
231 |
+
differentiate_finite, periodicity, not_empty_in, AccumBounds,
|
232 |
+
is_convex, stationary_points, minimum, maximum)
|
233 |
+
|
234 |
+
from .algebras import Quaternion
|
235 |
+
|
236 |
+
from .printing import (pager_print, pretty, pretty_print, pprint,
|
237 |
+
pprint_use_unicode, pprint_try_use_unicode, latex, print_latex,
|
238 |
+
multiline_latex, mathml, print_mathml, python, print_python, pycode,
|
239 |
+
ccode, print_ccode, smtlib_code, glsl_code, print_glsl, cxxcode, fcode,
|
240 |
+
print_fcode, rcode, print_rcode, jscode, print_jscode, julia_code,
|
241 |
+
mathematica_code, octave_code, rust_code, print_gtk, preview, srepr,
|
242 |
+
print_tree, StrPrinter, sstr, sstrrepr, TableForm, dotprint,
|
243 |
+
maple_code, print_maple_code)
|
244 |
+
|
245 |
+
test = lazy_function('sympy.testing.runtests', 'test')
|
246 |
+
doctest = lazy_function('sympy.testing.runtests', 'doctest')
|
247 |
+
|
248 |
+
# This module causes conflicts with other modules:
|
249 |
+
# from .stats import *
|
250 |
+
# Adds about .04-.05 seconds of import time
|
251 |
+
# from combinatorics import *
|
252 |
+
# This module is slow to import:
|
253 |
+
#from physics import units
|
254 |
+
from .plotting import plot, textplot, plot_backends, plot_implicit, plot_parametric
|
255 |
+
from .interactive import init_session, init_printing, interactive_traversal
|
256 |
+
|
257 |
+
evalf._create_evalf_table()
|
258 |
+
|
259 |
+
__all__ = [
|
260 |
+
'__version__',
|
261 |
+
|
262 |
+
# sympy.core
|
263 |
+
'sympify', 'SympifyError', 'cacheit', 'Basic', 'Atom',
|
264 |
+
'preorder_traversal', 'S', 'Expr', 'AtomicExpr', 'UnevaluatedExpr',
|
265 |
+
'Symbol', 'Wild', 'Dummy', 'symbols', 'var', 'Number', 'Float',
|
266 |
+
'Rational', 'Integer', 'NumberSymbol', 'RealNumber', 'igcd', 'ilcm',
|
267 |
+
'seterr', 'E', 'I', 'nan', 'oo', 'pi', 'zoo', 'AlgebraicNumber', 'comp',
|
268 |
+
'mod_inverse', 'Pow', 'integer_nthroot', 'integer_log', 'Mul', 'prod',
|
269 |
+
'Add', 'Mod', 'Rel', 'Eq', 'Ne', 'Lt', 'Le', 'Gt', 'Ge', 'Equality',
|
270 |
+
'GreaterThan', 'LessThan', 'Unequality', 'StrictGreaterThan',
|
271 |
+
'StrictLessThan', 'vectorize', 'Lambda', 'WildFunction', 'Derivative',
|
272 |
+
'diff', 'FunctionClass', 'Function', 'Subs', 'expand', 'PoleError',
|
273 |
+
'count_ops', 'expand_mul', 'expand_log', 'expand_func', 'expand_trig',
|
274 |
+
'expand_complex', 'expand_multinomial', 'nfloat', 'expand_power_base',
|
275 |
+
'expand_power_exp', 'arity', 'PrecisionExhausted', 'N', 'evalf', 'Tuple',
|
276 |
+
'Dict', 'gcd_terms', 'factor_terms', 'factor_nc', 'evaluate', 'Catalan',
|
277 |
+
'EulerGamma', 'GoldenRatio', 'TribonacciConstant', 'bottom_up', 'use',
|
278 |
+
'postorder_traversal', 'default_sort_key', 'ordered',
|
279 |
+
|
280 |
+
# sympy.logic
|
281 |
+
'to_cnf', 'to_dnf', 'to_nnf', 'And', 'Or', 'Not', 'Xor', 'Nand', 'Nor',
|
282 |
+
'Implies', 'Equivalent', 'ITE', 'POSform', 'SOPform', 'simplify_logic',
|
283 |
+
'bool_map', 'true', 'false', 'satisfiable',
|
284 |
+
|
285 |
+
# sympy.assumptions
|
286 |
+
'AppliedPredicate', 'Predicate', 'AssumptionsContext', 'assuming', 'Q',
|
287 |
+
'ask', 'register_handler', 'remove_handler', 'refine',
|
288 |
+
|
289 |
+
# sympy.polys
|
290 |
+
'Poly', 'PurePoly', 'poly_from_expr', 'parallel_poly_from_expr', 'degree',
|
291 |
+
'total_degree', 'degree_list', 'LC', 'LM', 'LT', 'pdiv', 'prem', 'pquo',
|
292 |
+
'pexquo', 'div', 'rem', 'quo', 'exquo', 'half_gcdex', 'gcdex', 'invert',
|
293 |
+
'subresultants', 'resultant', 'discriminant', 'cofactors', 'gcd_list',
|
294 |
+
'gcd', 'lcm_list', 'lcm', 'terms_gcd', 'trunc', 'monic', 'content',
|
295 |
+
'primitive', 'compose', 'decompose', 'sturm', 'gff_list', 'gff',
|
296 |
+
'sqf_norm', 'sqf_part', 'sqf_list', 'sqf', 'factor_list', 'factor',
|
297 |
+
'intervals', 'refine_root', 'count_roots', 'real_roots', 'nroots',
|
298 |
+
'ground_roots', 'nth_power_roots_poly', 'cancel', 'reduced', 'groebner',
|
299 |
+
'is_zero_dimensional', 'GroebnerBasis', 'poly', 'symmetrize', 'horner',
|
300 |
+
'interpolate', 'rational_interpolate', 'viete', 'together',
|
301 |
+
'BasePolynomialError', 'ExactQuotientFailed', 'PolynomialDivisionFailed',
|
302 |
+
'OperationNotSupported', 'HeuristicGCDFailed', 'HomomorphismFailed',
|
303 |
+
'IsomorphismFailed', 'ExtraneousFactors', 'EvaluationFailed',
|
304 |
+
'RefinementFailed', 'CoercionFailed', 'NotInvertible', 'NotReversible',
|
305 |
+
'NotAlgebraic', 'DomainError', 'PolynomialError', 'UnificationFailed',
|
306 |
+
'GeneratorsError', 'GeneratorsNeeded', 'ComputationFailed',
|
307 |
+
'UnivariatePolynomialError', 'MultivariatePolynomialError',
|
308 |
+
'PolificationFailed', 'OptionError', 'FlagError', 'minpoly',
|
309 |
+
'minimal_polynomial', 'primitive_element', 'field_isomorphism',
|
310 |
+
'to_number_field', 'isolate', 'round_two', 'prime_decomp',
|
311 |
+
'prime_valuation', 'galois_group', 'itermonomials', 'Monomial', 'lex', 'grlex',
|
312 |
+
'grevlex', 'ilex', 'igrlex', 'igrevlex', 'CRootOf', 'rootof', 'RootOf',
|
313 |
+
'ComplexRootOf', 'RootSum', 'roots', 'Domain', 'FiniteField',
|
314 |
+
'IntegerRing', 'RationalField', 'RealField', 'ComplexField',
|
315 |
+
'PythonFiniteField', 'GMPYFiniteField', 'PythonIntegerRing',
|
316 |
+
'GMPYIntegerRing', 'PythonRational', 'GMPYRationalField',
|
317 |
+
'AlgebraicField', 'PolynomialRing', 'FractionField', 'ExpressionDomain',
|
318 |
+
'FF_python', 'FF_gmpy', 'ZZ_python', 'ZZ_gmpy', 'QQ_python', 'QQ_gmpy',
|
319 |
+
'GF', 'FF', 'ZZ', 'QQ', 'ZZ_I', 'QQ_I', 'RR', 'CC', 'EX', 'EXRAW',
|
320 |
+
'construct_domain', 'swinnerton_dyer_poly', 'cyclotomic_poly',
|
321 |
+
'symmetric_poly', 'random_poly', 'interpolating_poly', 'jacobi_poly',
|
322 |
+
'chebyshevt_poly', 'chebyshevu_poly', 'hermite_poly', 'hermite_prob_poly',
|
323 |
+
'legendre_poly', 'laguerre_poly', 'apart', 'apart_list', 'assemble_partfrac_list',
|
324 |
+
'Options', 'ring', 'xring', 'vring', 'sring', 'field', 'xfield', 'vfield',
|
325 |
+
'sfield',
|
326 |
+
|
327 |
+
# sympy.series
|
328 |
+
'Order', 'O', 'limit', 'Limit', 'gruntz', 'series', 'approximants',
|
329 |
+
'residue', 'EmptySequence', 'SeqPer', 'SeqFormula', 'sequence', 'SeqAdd',
|
330 |
+
'SeqMul', 'fourier_series', 'fps', 'difference_delta', 'limit_seq',
|
331 |
+
|
332 |
+
# sympy.functions
|
333 |
+
'factorial', 'factorial2', 'rf', 'ff', 'binomial', 'RisingFactorial',
|
334 |
+
'FallingFactorial', 'subfactorial', 'carmichael', 'fibonacci', 'lucas',
|
335 |
+
'motzkin', 'tribonacci', 'harmonic', 'bernoulli', 'bell', 'euler', 'catalan',
|
336 |
+
'genocchi', 'andre', 'partition', 'sqrt', 'root', 'Min', 'Max', 'Id', 'real_root',
|
337 |
+
'Rem', 'cbrt', 're', 'im', 'sign', 'Abs', 'conjugate', 'arg', 'polar_lift',
|
338 |
+
'periodic_argument', 'unbranched_argument', 'principal_branch',
|
339 |
+
'transpose', 'adjoint', 'polarify', 'unpolarify', 'sin', 'cos', 'tan',
|
340 |
+
'sec', 'csc', 'cot', 'sinc', 'asin', 'acos', 'atan', 'asec', 'acsc',
|
341 |
+
'acot', 'atan2', 'exp_polar', 'exp', 'ln', 'log', 'LambertW', 'sinh',
|
342 |
+
'cosh', 'tanh', 'coth', 'sech', 'csch', 'asinh', 'acosh', 'atanh',
|
343 |
+
'acoth', 'asech', 'acsch', 'floor', 'ceiling', 'frac', 'Piecewise',
|
344 |
+
'piecewise_fold', 'piecewise_exclusive', 'erf', 'erfc', 'erfi', 'erf2',
|
345 |
+
'erfinv', 'erfcinv', 'erf2inv', 'Ei', 'expint', 'E1', 'li', 'Li', 'Si',
|
346 |
+
'Ci', 'Shi', 'Chi', 'fresnels', 'fresnelc', 'gamma', 'lowergamma',
|
347 |
+
'uppergamma', 'polygamma', 'loggamma', 'digamma', 'trigamma', 'multigamma',
|
348 |
+
'dirichlet_eta', 'zeta', 'lerchphi', 'polylog', 'stieltjes', 'Eijk', 'LeviCivita',
|
349 |
+
'KroneckerDelta', 'SingularityFunction', 'DiracDelta', 'Heaviside',
|
350 |
+
'bspline_basis', 'bspline_basis_set', 'interpolating_spline', 'besselj',
|
351 |
+
'bessely', 'besseli', 'besselk', 'hankel1', 'hankel2', 'jn', 'yn',
|
352 |
+
'jn_zeros', 'hn1', 'hn2', 'airyai', 'airybi', 'airyaiprime',
|
353 |
+
'airybiprime', 'marcumq', 'hyper', 'meijerg', 'appellf1', 'legendre',
|
354 |
+
'assoc_legendre', 'hermite', 'hermite_prob', 'chebyshevt', 'chebyshevu',
|
355 |
+
'chebyshevu_root', 'chebyshevt_root', 'laguerre', 'assoc_laguerre',
|
356 |
+
'gegenbauer', 'jacobi', 'jacobi_normalized', 'Ynm', 'Ynm_c', 'Znm',
|
357 |
+
'elliptic_k', 'elliptic_f', 'elliptic_e', 'elliptic_pi', 'beta',
|
358 |
+
'mathieus', 'mathieuc', 'mathieusprime', 'mathieucprime', 'riemann_xi','betainc',
|
359 |
+
'betainc_regularized',
|
360 |
+
|
361 |
+
# sympy.ntheory
|
362 |
+
'nextprime', 'prevprime', 'prime', 'primepi', 'primerange', 'randprime',
|
363 |
+
'Sieve', 'sieve', 'primorial', 'cycle_length', 'composite', 'compositepi',
|
364 |
+
'isprime', 'divisors', 'proper_divisors', 'factorint', 'multiplicity',
|
365 |
+
'perfect_power', 'pollard_pm1', 'pollard_rho', 'primefactors', 'totient',
|
366 |
+
'trailing', 'divisor_count', 'proper_divisor_count', 'divisor_sigma',
|
367 |
+
'factorrat', 'reduced_totient', 'primenu', 'primeomega',
|
368 |
+
'mersenne_prime_exponent', 'is_perfect', 'is_mersenne_prime',
|
369 |
+
'is_abundant', 'is_deficient', 'is_amicable', 'abundance', 'npartitions',
|
370 |
+
'is_primitive_root', 'is_quad_residue', 'legendre_symbol',
|
371 |
+
'jacobi_symbol', 'n_order', 'sqrt_mod', 'quadratic_residues',
|
372 |
+
'primitive_root', 'nthroot_mod', 'is_nthpow_residue', 'sqrt_mod_iter',
|
373 |
+
'mobius', 'discrete_log', 'quadratic_congruence', 'binomial_coefficients',
|
374 |
+
'binomial_coefficients_list', 'multinomial_coefficients',
|
375 |
+
'continued_fraction_periodic', 'continued_fraction_iterator',
|
376 |
+
'continued_fraction_reduce', 'continued_fraction_convergents',
|
377 |
+
'continued_fraction', 'egyptian_fraction',
|
378 |
+
|
379 |
+
# sympy.concrete
|
380 |
+
'product', 'Product', 'summation', 'Sum',
|
381 |
+
|
382 |
+
# sympy.discrete
|
383 |
+
'fft', 'ifft', 'ntt', 'intt', 'fwht', 'ifwht', 'mobius_transform',
|
384 |
+
'inverse_mobius_transform', 'convolution', 'covering_product',
|
385 |
+
'intersecting_product',
|
386 |
+
|
387 |
+
# sympy.simplify
|
388 |
+
'simplify', 'hypersimp', 'hypersimilar', 'logcombine', 'separatevars',
|
389 |
+
'posify', 'besselsimp', 'kroneckersimp', 'signsimp',
|
390 |
+
'nsimplify', 'FU', 'fu', 'sqrtdenest', 'cse', 'epath', 'EPath',
|
391 |
+
'hyperexpand', 'collect', 'rcollect', 'radsimp', 'collect_const',
|
392 |
+
'fraction', 'numer', 'denom', 'trigsimp', 'exptrigsimp', 'powsimp',
|
393 |
+
'powdenest', 'combsimp', 'gammasimp', 'ratsimp', 'ratsimpmodprime',
|
394 |
+
|
395 |
+
# sympy.sets
|
396 |
+
'Set', 'Interval', 'Union', 'EmptySet', 'FiniteSet', 'ProductSet',
|
397 |
+
'Intersection', 'imageset', 'DisjointUnion', 'Complement', 'SymmetricDifference',
|
398 |
+
'ImageSet', 'Range', 'ComplexRegion', 'Reals', 'Contains', 'ConditionSet',
|
399 |
+
'Ordinal', 'OmegaPower', 'ord0', 'PowerSet', 'Naturals',
|
400 |
+
'Naturals0', 'UniversalSet', 'Integers', 'Rationals', 'Complexes',
|
401 |
+
|
402 |
+
# sympy.solvers
|
403 |
+
'solve', 'solve_linear_system', 'solve_linear_system_LU',
|
404 |
+
'solve_undetermined_coeffs', 'nsolve', 'solve_linear', 'checksol',
|
405 |
+
'det_quick', 'inv_quick', 'check_assumptions', 'failing_assumptions',
|
406 |
+
'diophantine', 'rsolve', 'rsolve_poly', 'rsolve_ratio', 'rsolve_hyper',
|
407 |
+
'checkodesol', 'classify_ode', 'dsolve', 'homogeneous_order',
|
408 |
+
'solve_poly_system', 'solve_triangulated', 'pde_separate',
|
409 |
+
'pde_separate_add', 'pde_separate_mul', 'pdsolve', 'classify_pde',
|
410 |
+
'checkpdesol', 'ode_order', 'reduce_inequalities',
|
411 |
+
'reduce_abs_inequality', 'reduce_abs_inequalities',
|
412 |
+
'solve_poly_inequality', 'solve_rational_inequalities',
|
413 |
+
'solve_univariate_inequality', 'decompogen', 'solveset', 'linsolve',
|
414 |
+
'linear_eq_to_matrix', 'nonlinsolve', 'substitution',
|
415 |
+
|
416 |
+
# sympy.matrices
|
417 |
+
'ShapeError', 'NonSquareMatrixError', 'GramSchmidt', 'casoratian', 'diag',
|
418 |
+
'eye', 'hessian', 'jordan_cell', 'list2numpy', 'matrix2numpy',
|
419 |
+
'matrix_multiply_elementwise', 'ones', 'randMatrix', 'rot_axis1',
|
420 |
+
'rot_axis2', 'rot_axis3', 'symarray', 'wronskian', 'zeros',
|
421 |
+
'MutableDenseMatrix', 'DeferredVector', 'MatrixBase', 'Matrix',
|
422 |
+
'MutableMatrix', 'MutableSparseMatrix', 'banded', 'ImmutableDenseMatrix',
|
423 |
+
'ImmutableSparseMatrix', 'ImmutableMatrix', 'SparseMatrix', 'MatrixSlice',
|
424 |
+
'BlockDiagMatrix', 'BlockMatrix', 'FunctionMatrix', 'Identity', 'Inverse',
|
425 |
+
'MatAdd', 'MatMul', 'MatPow', 'MatrixExpr', 'MatrixSymbol', 'Trace',
|
426 |
+
'Transpose', 'ZeroMatrix', 'OneMatrix', 'blockcut', 'block_collapse',
|
427 |
+
'matrix_symbols', 'Adjoint', 'hadamard_product', 'HadamardProduct',
|
428 |
+
'HadamardPower', 'Determinant', 'det', 'diagonalize_vector', 'DiagMatrix',
|
429 |
+
'DiagonalMatrix', 'DiagonalOf', 'trace', 'DotProduct',
|
430 |
+
'kronecker_product', 'KroneckerProduct', 'PermutationMatrix',
|
431 |
+
'MatrixPermute', 'Permanent', 'per', 'rot_ccw_axis1', 'rot_ccw_axis2',
|
432 |
+
'rot_ccw_axis3', 'rot_givens',
|
433 |
+
|
434 |
+
# sympy.geometry
|
435 |
+
'Point', 'Point2D', 'Point3D', 'Line', 'Ray', 'Segment', 'Line2D',
|
436 |
+
'Segment2D', 'Ray2D', 'Line3D', 'Segment3D', 'Ray3D', 'Plane', 'Ellipse',
|
437 |
+
'Circle', 'Polygon', 'RegularPolygon', 'Triangle', 'rad', 'deg',
|
438 |
+
'are_similar', 'centroid', 'convex_hull', 'idiff', 'intersection',
|
439 |
+
'closest_points', 'farthest_points', 'GeometryError', 'Curve', 'Parabola',
|
440 |
+
|
441 |
+
# sympy.utilities
|
442 |
+
'flatten', 'group', 'take', 'subsets', 'variations', 'numbered_symbols',
|
443 |
+
'cartes', 'capture', 'dict_merge', 'prefixes', 'postfixes', 'sift',
|
444 |
+
'topological_sort', 'unflatten', 'has_dups', 'has_variety', 'reshape',
|
445 |
+
'rotations', 'filldedent', 'lambdify', 'threaded', 'xthreaded',
|
446 |
+
'public', 'memoize_property', 'timed',
|
447 |
+
|
448 |
+
# sympy.integrals
|
449 |
+
'integrate', 'Integral', 'line_integrate', 'mellin_transform',
|
450 |
+
'inverse_mellin_transform', 'MellinTransform', 'InverseMellinTransform',
|
451 |
+
'laplace_transform', 'inverse_laplace_transform', 'LaplaceTransform',
|
452 |
+
'InverseLaplaceTransform', 'fourier_transform',
|
453 |
+
'inverse_fourier_transform', 'FourierTransform',
|
454 |
+
'InverseFourierTransform', 'sine_transform', 'inverse_sine_transform',
|
455 |
+
'SineTransform', 'InverseSineTransform', 'cosine_transform',
|
456 |
+
'inverse_cosine_transform', 'CosineTransform', 'InverseCosineTransform',
|
457 |
+
'hankel_transform', 'inverse_hankel_transform', 'HankelTransform',
|
458 |
+
'InverseHankelTransform', 'singularityintegrate',
|
459 |
+
|
460 |
+
# sympy.tensor
|
461 |
+
'IndexedBase', 'Idx', 'Indexed', 'get_contraction_structure',
|
462 |
+
'get_indices', 'shape', 'MutableDenseNDimArray', 'ImmutableDenseNDimArray',
|
463 |
+
'MutableSparseNDimArray', 'ImmutableSparseNDimArray', 'NDimArray',
|
464 |
+
'tensorproduct', 'tensorcontraction', 'tensordiagonal', 'derive_by_array',
|
465 |
+
'permutedims', 'Array', 'DenseNDimArray', 'SparseNDimArray',
|
466 |
+
|
467 |
+
# sympy.parsing
|
468 |
+
'parse_expr',
|
469 |
+
|
470 |
+
# sympy.calculus
|
471 |
+
'euler_equations', 'singularities', 'is_increasing',
|
472 |
+
'is_strictly_increasing', 'is_decreasing', 'is_strictly_decreasing',
|
473 |
+
'is_monotonic', 'finite_diff_weights', 'apply_finite_diff',
|
474 |
+
'differentiate_finite', 'periodicity', 'not_empty_in',
|
475 |
+
'AccumBounds', 'is_convex', 'stationary_points', 'minimum', 'maximum',
|
476 |
+
|
477 |
+
# sympy.algebras
|
478 |
+
'Quaternion',
|
479 |
+
|
480 |
+
# sympy.printing
|
481 |
+
'pager_print', 'pretty', 'pretty_print', 'pprint', 'pprint_use_unicode',
|
482 |
+
'pprint_try_use_unicode', 'latex', 'print_latex', 'multiline_latex',
|
483 |
+
'mathml', 'print_mathml', 'python', 'print_python', 'pycode', 'ccode',
|
484 |
+
'print_ccode', 'smtlib_code', 'glsl_code', 'print_glsl', 'cxxcode', 'fcode',
|
485 |
+
'print_fcode', 'rcode', 'print_rcode', 'jscode', 'print_jscode',
|
486 |
+
'julia_code', 'mathematica_code', 'octave_code', 'rust_code', 'print_gtk',
|
487 |
+
'preview', 'srepr', 'print_tree', 'StrPrinter', 'sstr', 'sstrrepr',
|
488 |
+
'TableForm', 'dotprint', 'maple_code', 'print_maple_code',
|
489 |
+
|
490 |
+
# sympy.plotting
|
491 |
+
'plot', 'textplot', 'plot_backends', 'plot_implicit', 'plot_parametric',
|
492 |
+
|
493 |
+
# sympy.interactive
|
494 |
+
'init_session', 'init_printing', 'interactive_traversal',
|
495 |
+
|
496 |
+
# sympy.testing
|
497 |
+
'test', 'doctest',
|
498 |
+
]
|
499 |
+
|
500 |
+
|
501 |
+
#===========================================================================#
|
502 |
+
# #
|
503 |
+
# XXX: The names below were importable before SymPy 1.6 using #
|
504 |
+
# #
|
505 |
+
# from sympy import * #
|
506 |
+
# #
|
507 |
+
# This happened implicitly because there was no __all__ defined in this #
|
508 |
+
# __init__.py file. Not every package is imported. The list matches what #
|
509 |
+
# would have been imported before. It is possible that these packages will #
|
510 |
+
# not be imported by a star-import from sympy in future. #
|
511 |
+
# #
|
512 |
+
#===========================================================================#
|
513 |
+
|
514 |
+
|
515 |
+
__all__.extend((
|
516 |
+
'algebras',
|
517 |
+
'assumptions',
|
518 |
+
'calculus',
|
519 |
+
'concrete',
|
520 |
+
'discrete',
|
521 |
+
'external',
|
522 |
+
'functions',
|
523 |
+
'geometry',
|
524 |
+
'interactive',
|
525 |
+
'multipledispatch',
|
526 |
+
'ntheory',
|
527 |
+
'parsing',
|
528 |
+
'plotting',
|
529 |
+
'polys',
|
530 |
+
'printing',
|
531 |
+
'release',
|
532 |
+
'strategies',
|
533 |
+
'tensor',
|
534 |
+
'utilities',
|
535 |
+
))
|
llmeval-env/lib/python3.10/site-packages/sympy/abc.py
ADDED
@@ -0,0 +1,111 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
"""
|
2 |
+
This module exports all latin and greek letters as Symbols, so you can
|
3 |
+
conveniently do
|
4 |
+
|
5 |
+
>>> from sympy.abc import x, y
|
6 |
+
|
7 |
+
instead of the slightly more clunky-looking
|
8 |
+
|
9 |
+
>>> from sympy import symbols
|
10 |
+
>>> x, y = symbols('x y')
|
11 |
+
|
12 |
+
Caveats
|
13 |
+
=======
|
14 |
+
|
15 |
+
1. As of the time of writing this, the names ``O``, ``S``, ``I``, ``N``,
|
16 |
+
``E``, and ``Q`` are colliding with names defined in SymPy. If you import them
|
17 |
+
from both ``sympy.abc`` and ``sympy``, the second import will "win".
|
18 |
+
This is an issue only for * imports, which should only be used for short-lived
|
19 |
+
code such as interactive sessions and throwaway scripts that do not survive
|
20 |
+
until the next SymPy upgrade, where ``sympy`` may contain a different set of
|
21 |
+
names.
|
22 |
+
|
23 |
+
2. This module does not define symbol names on demand, i.e.
|
24 |
+
``from sympy.abc import foo`` will be reported as an error because
|
25 |
+
``sympy.abc`` does not contain the name ``foo``. To get a symbol named ``foo``,
|
26 |
+
you still need to use ``Symbol('foo')`` or ``symbols('foo')``.
|
27 |
+
You can freely mix usage of ``sympy.abc`` and ``Symbol``/``symbols``, though
|
28 |
+
sticking with one and only one way to get the symbols does tend to make the code
|
29 |
+
more readable.
|
30 |
+
|
31 |
+
The module also defines some special names to help detect which names clash
|
32 |
+
with the default SymPy namespace.
|
33 |
+
|
34 |
+
``_clash1`` defines all the single letter variables that clash with
|
35 |
+
SymPy objects; ``_clash2`` defines the multi-letter clashing symbols;
|
36 |
+
and ``_clash`` is the union of both. These can be passed for ``locals``
|
37 |
+
during sympification if one desires Symbols rather than the non-Symbol
|
38 |
+
objects for those names.
|
39 |
+
|
40 |
+
Examples
|
41 |
+
========
|
42 |
+
|
43 |
+
>>> from sympy import S
|
44 |
+
>>> from sympy.abc import _clash1, _clash2, _clash
|
45 |
+
>>> S("Q & C", locals=_clash1)
|
46 |
+
C & Q
|
47 |
+
>>> S('pi(x)', locals=_clash2)
|
48 |
+
pi(x)
|
49 |
+
>>> S('pi(C, Q)', locals=_clash)
|
50 |
+
pi(C, Q)
|
51 |
+
|
52 |
+
"""
|
53 |
+
|
54 |
+
from typing import Any, Dict as tDict
|
55 |
+
|
56 |
+
import string
|
57 |
+
|
58 |
+
from .core import Symbol, symbols
|
59 |
+
from .core.alphabets import greeks
|
60 |
+
from sympy.parsing.sympy_parser import null
|
61 |
+
|
62 |
+
##### Symbol definitions #####
|
63 |
+
|
64 |
+
# Implementation note: The easiest way to avoid typos in the symbols()
|
65 |
+
# parameter is to copy it from the left-hand side of the assignment.
|
66 |
+
|
67 |
+
a, b, c, d, e, f, g, h, i, j = symbols('a, b, c, d, e, f, g, h, i, j')
|
68 |
+
k, l, m, n, o, p, q, r, s, t = symbols('k, l, m, n, o, p, q, r, s, t')
|
69 |
+
u, v, w, x, y, z = symbols('u, v, w, x, y, z')
|
70 |
+
|
71 |
+
A, B, C, D, E, F, G, H, I, J = symbols('A, B, C, D, E, F, G, H, I, J')
|
72 |
+
K, L, M, N, O, P, Q, R, S, T = symbols('K, L, M, N, O, P, Q, R, S, T')
|
73 |
+
U, V, W, X, Y, Z = symbols('U, V, W, X, Y, Z')
|
74 |
+
|
75 |
+
alpha, beta, gamma, delta = symbols('alpha, beta, gamma, delta')
|
76 |
+
epsilon, zeta, eta, theta = symbols('epsilon, zeta, eta, theta')
|
77 |
+
iota, kappa, lamda, mu = symbols('iota, kappa, lamda, mu')
|
78 |
+
nu, xi, omicron, pi = symbols('nu, xi, omicron, pi')
|
79 |
+
rho, sigma, tau, upsilon = symbols('rho, sigma, tau, upsilon')
|
80 |
+
phi, chi, psi, omega = symbols('phi, chi, psi, omega')
|
81 |
+
|
82 |
+
|
83 |
+
##### Clashing-symbols diagnostics #####
|
84 |
+
|
85 |
+
# We want to know which names in SymPy collide with those in here.
|
86 |
+
# This is mostly for diagnosing SymPy's namespace during SymPy development.
|
87 |
+
|
88 |
+
_latin = list(string.ascii_letters)
|
89 |
+
# QOSINE should not be imported as they clash; gamma, pi and zeta clash, too
|
90 |
+
_greek = list(greeks) # make a copy, so we can mutate it
|
91 |
+
# Note: We import lamda since lambda is a reserved keyword in Python
|
92 |
+
_greek.remove("lambda")
|
93 |
+
_greek.append("lamda")
|
94 |
+
|
95 |
+
ns: tDict[str, Any] = {}
|
96 |
+
exec('from sympy import *', ns)
|
97 |
+
_clash1: tDict[str, Any] = {}
|
98 |
+
_clash2: tDict[str, Any] = {}
|
99 |
+
while ns:
|
100 |
+
_k, _ = ns.popitem()
|
101 |
+
if _k in _greek:
|
102 |
+
_clash2[_k] = null
|
103 |
+
_greek.remove(_k)
|
104 |
+
elif _k in _latin:
|
105 |
+
_clash1[_k] = null
|
106 |
+
_latin.remove(_k)
|
107 |
+
_clash = {}
|
108 |
+
_clash.update(_clash1)
|
109 |
+
_clash.update(_clash2)
|
110 |
+
|
111 |
+
del _latin, _greek, Symbol, _k, null
|
llmeval-env/lib/python3.10/site-packages/sympy/conftest.py
ADDED
@@ -0,0 +1,74 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
import sys
|
2 |
+
sys._running_pytest = True # type: ignore
|
3 |
+
from sympy.external.importtools import version_tuple
|
4 |
+
|
5 |
+
import pytest
|
6 |
+
from sympy.core.cache import clear_cache, USE_CACHE
|
7 |
+
from sympy.external.gmpy import GROUND_TYPES, HAS_GMPY
|
8 |
+
from sympy.utilities.misc import ARCH
|
9 |
+
import re
|
10 |
+
|
11 |
+
sp = re.compile(r'([0-9]+)/([1-9][0-9]*)')
|
12 |
+
|
13 |
+
def process_split(config, items):
|
14 |
+
split = config.getoption("--split")
|
15 |
+
if not split:
|
16 |
+
return
|
17 |
+
m = sp.match(split)
|
18 |
+
if not m:
|
19 |
+
raise ValueError("split must be a string of the form a/b "
|
20 |
+
"where a and b are ints.")
|
21 |
+
i, t = map(int, m.groups())
|
22 |
+
start, end = (i-1)*len(items)//t, i*len(items)//t
|
23 |
+
|
24 |
+
if i < t:
|
25 |
+
# remove elements from end of list first
|
26 |
+
del items[end:]
|
27 |
+
del items[:start]
|
28 |
+
|
29 |
+
|
30 |
+
def pytest_report_header(config):
|
31 |
+
s = "architecture: %s\n" % ARCH
|
32 |
+
s += "cache: %s\n" % USE_CACHE
|
33 |
+
version = ''
|
34 |
+
if GROUND_TYPES =='gmpy':
|
35 |
+
if HAS_GMPY == 1:
|
36 |
+
import gmpy
|
37 |
+
elif HAS_GMPY == 2:
|
38 |
+
import gmpy2 as gmpy
|
39 |
+
version = gmpy.version()
|
40 |
+
s += "ground types: %s %s\n" % (GROUND_TYPES, version)
|
41 |
+
return s
|
42 |
+
|
43 |
+
|
44 |
+
def pytest_terminal_summary(terminalreporter):
|
45 |
+
if (terminalreporter.stats.get('error', None) or
|
46 |
+
terminalreporter.stats.get('failed', None)):
|
47 |
+
terminalreporter.write_sep(
|
48 |
+
' ', 'DO *NOT* COMMIT!', red=True, bold=True)
|
49 |
+
|
50 |
+
|
51 |
+
def pytest_addoption(parser):
|
52 |
+
parser.addoption("--split", action="store", default="",
|
53 |
+
help="split tests")
|
54 |
+
|
55 |
+
|
56 |
+
def pytest_collection_modifyitems(config, items):
|
57 |
+
""" pytest hook. """
|
58 |
+
# handle splits
|
59 |
+
process_split(config, items)
|
60 |
+
|
61 |
+
|
62 |
+
@pytest.fixture(autouse=True, scope='module')
|
63 |
+
def file_clear_cache():
|
64 |
+
clear_cache()
|
65 |
+
|
66 |
+
@pytest.fixture(autouse=True, scope='module')
|
67 |
+
def check_disabled(request):
|
68 |
+
if getattr(request.module, 'disabled', False):
|
69 |
+
pytest.skip("test requirements not met.")
|
70 |
+
elif getattr(request.module, 'ipython', False):
|
71 |
+
# need to check version and options for ipython tests
|
72 |
+
if (version_tuple(pytest.__version__) < version_tuple('2.6.3') and
|
73 |
+
pytest.config.getvalue('-s') != 'no'):
|
74 |
+
pytest.skip("run py.test with -s or upgrade to newer version.")
|
llmeval-env/lib/python3.10/site-packages/sympy/galgebra.py
ADDED
@@ -0,0 +1 @@
|
|
|
|
|
1 |
+
raise ImportError("""As of SymPy 1.0 the galgebra module is maintained separately at https://github.com/pygae/galgebra""")
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/hydrogen.py
ADDED
@@ -0,0 +1,265 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.core.numbers import Float
|
2 |
+
from sympy.core.singleton import S
|
3 |
+
from sympy.functions.combinatorial.factorials import factorial
|
4 |
+
from sympy.functions.elementary.exponential import exp
|
5 |
+
from sympy.functions.elementary.miscellaneous import sqrt
|
6 |
+
from sympy.functions.special.polynomials import assoc_laguerre
|
7 |
+
from sympy.functions.special.spherical_harmonics import Ynm
|
8 |
+
|
9 |
+
|
10 |
+
def R_nl(n, l, r, Z=1):
|
11 |
+
"""
|
12 |
+
Returns the Hydrogen radial wavefunction R_{nl}.
|
13 |
+
|
14 |
+
Parameters
|
15 |
+
==========
|
16 |
+
|
17 |
+
n : integer
|
18 |
+
Principal Quantum Number which is
|
19 |
+
an integer with possible values as 1, 2, 3, 4,...
|
20 |
+
l : integer
|
21 |
+
``l`` is the Angular Momentum Quantum Number with
|
22 |
+
values ranging from 0 to ``n-1``.
|
23 |
+
r :
|
24 |
+
Radial coordinate.
|
25 |
+
Z :
|
26 |
+
Atomic number (1 for Hydrogen, 2 for Helium, ...)
|
27 |
+
|
28 |
+
Everything is in Hartree atomic units.
|
29 |
+
|
30 |
+
Examples
|
31 |
+
========
|
32 |
+
|
33 |
+
>>> from sympy.physics.hydrogen import R_nl
|
34 |
+
>>> from sympy.abc import r, Z
|
35 |
+
>>> R_nl(1, 0, r, Z)
|
36 |
+
2*sqrt(Z**3)*exp(-Z*r)
|
37 |
+
>>> R_nl(2, 0, r, Z)
|
38 |
+
sqrt(2)*(-Z*r + 2)*sqrt(Z**3)*exp(-Z*r/2)/4
|
39 |
+
>>> R_nl(2, 1, r, Z)
|
40 |
+
sqrt(6)*Z*r*sqrt(Z**3)*exp(-Z*r/2)/12
|
41 |
+
|
42 |
+
For Hydrogen atom, you can just use the default value of Z=1:
|
43 |
+
|
44 |
+
>>> R_nl(1, 0, r)
|
45 |
+
2*exp(-r)
|
46 |
+
>>> R_nl(2, 0, r)
|
47 |
+
sqrt(2)*(2 - r)*exp(-r/2)/4
|
48 |
+
>>> R_nl(3, 0, r)
|
49 |
+
2*sqrt(3)*(2*r**2/9 - 2*r + 3)*exp(-r/3)/27
|
50 |
+
|
51 |
+
For Silver atom, you would use Z=47:
|
52 |
+
|
53 |
+
>>> R_nl(1, 0, r, Z=47)
|
54 |
+
94*sqrt(47)*exp(-47*r)
|
55 |
+
>>> R_nl(2, 0, r, Z=47)
|
56 |
+
47*sqrt(94)*(2 - 47*r)*exp(-47*r/2)/4
|
57 |
+
>>> R_nl(3, 0, r, Z=47)
|
58 |
+
94*sqrt(141)*(4418*r**2/9 - 94*r + 3)*exp(-47*r/3)/27
|
59 |
+
|
60 |
+
The normalization of the radial wavefunction is:
|
61 |
+
|
62 |
+
>>> from sympy import integrate, oo
|
63 |
+
>>> integrate(R_nl(1, 0, r)**2 * r**2, (r, 0, oo))
|
64 |
+
1
|
65 |
+
>>> integrate(R_nl(2, 0, r)**2 * r**2, (r, 0, oo))
|
66 |
+
1
|
67 |
+
>>> integrate(R_nl(2, 1, r)**2 * r**2, (r, 0, oo))
|
68 |
+
1
|
69 |
+
|
70 |
+
It holds for any atomic number:
|
71 |
+
|
72 |
+
>>> integrate(R_nl(1, 0, r, Z=2)**2 * r**2, (r, 0, oo))
|
73 |
+
1
|
74 |
+
>>> integrate(R_nl(2, 0, r, Z=3)**2 * r**2, (r, 0, oo))
|
75 |
+
1
|
76 |
+
>>> integrate(R_nl(2, 1, r, Z=4)**2 * r**2, (r, 0, oo))
|
77 |
+
1
|
78 |
+
|
79 |
+
"""
|
80 |
+
# sympify arguments
|
81 |
+
n, l, r, Z = map(S, [n, l, r, Z])
|
82 |
+
# radial quantum number
|
83 |
+
n_r = n - l - 1
|
84 |
+
# rescaled "r"
|
85 |
+
a = 1/Z # Bohr radius
|
86 |
+
r0 = 2 * r / (n * a)
|
87 |
+
# normalization coefficient
|
88 |
+
C = sqrt((S(2)/(n*a))**3 * factorial(n_r) / (2*n*factorial(n + l)))
|
89 |
+
# This is an equivalent normalization coefficient, that can be found in
|
90 |
+
# some books. Both coefficients seem to be the same fast:
|
91 |
+
# C = S(2)/n**2 * sqrt(1/a**3 * factorial(n_r) / (factorial(n+l)))
|
92 |
+
return C * r0**l * assoc_laguerre(n_r, 2*l + 1, r0).expand() * exp(-r0/2)
|
93 |
+
|
94 |
+
|
95 |
+
def Psi_nlm(n, l, m, r, phi, theta, Z=1):
|
96 |
+
"""
|
97 |
+
Returns the Hydrogen wave function psi_{nlm}. It's the product of
|
98 |
+
the radial wavefunction R_{nl} and the spherical harmonic Y_{l}^{m}.
|
99 |
+
|
100 |
+
Parameters
|
101 |
+
==========
|
102 |
+
|
103 |
+
n : integer
|
104 |
+
Principal Quantum Number which is
|
105 |
+
an integer with possible values as 1, 2, 3, 4,...
|
106 |
+
l : integer
|
107 |
+
``l`` is the Angular Momentum Quantum Number with
|
108 |
+
values ranging from 0 to ``n-1``.
|
109 |
+
m : integer
|
110 |
+
``m`` is the Magnetic Quantum Number with values
|
111 |
+
ranging from ``-l`` to ``l``.
|
112 |
+
r :
|
113 |
+
radial coordinate
|
114 |
+
phi :
|
115 |
+
azimuthal angle
|
116 |
+
theta :
|
117 |
+
polar angle
|
118 |
+
Z :
|
119 |
+
atomic number (1 for Hydrogen, 2 for Helium, ...)
|
120 |
+
|
121 |
+
Everything is in Hartree atomic units.
|
122 |
+
|
123 |
+
Examples
|
124 |
+
========
|
125 |
+
|
126 |
+
>>> from sympy.physics.hydrogen import Psi_nlm
|
127 |
+
>>> from sympy import Symbol
|
128 |
+
>>> r=Symbol("r", positive=True)
|
129 |
+
>>> phi=Symbol("phi", real=True)
|
130 |
+
>>> theta=Symbol("theta", real=True)
|
131 |
+
>>> Z=Symbol("Z", positive=True, integer=True, nonzero=True)
|
132 |
+
>>> Psi_nlm(1,0,0,r,phi,theta,Z)
|
133 |
+
Z**(3/2)*exp(-Z*r)/sqrt(pi)
|
134 |
+
>>> Psi_nlm(2,1,1,r,phi,theta,Z)
|
135 |
+
-Z**(5/2)*r*exp(I*phi)*exp(-Z*r/2)*sin(theta)/(8*sqrt(pi))
|
136 |
+
|
137 |
+
Integrating the absolute square of a hydrogen wavefunction psi_{nlm}
|
138 |
+
over the whole space leads 1.
|
139 |
+
|
140 |
+
The normalization of the hydrogen wavefunctions Psi_nlm is:
|
141 |
+
|
142 |
+
>>> from sympy import integrate, conjugate, pi, oo, sin
|
143 |
+
>>> wf=Psi_nlm(2,1,1,r,phi,theta,Z)
|
144 |
+
>>> abs_sqrd=wf*conjugate(wf)
|
145 |
+
>>> jacobi=r**2*sin(theta)
|
146 |
+
>>> integrate(abs_sqrd*jacobi, (r,0,oo), (phi,0,2*pi), (theta,0,pi))
|
147 |
+
1
|
148 |
+
"""
|
149 |
+
|
150 |
+
# sympify arguments
|
151 |
+
n, l, m, r, phi, theta, Z = map(S, [n, l, m, r, phi, theta, Z])
|
152 |
+
# check if values for n,l,m make physically sense
|
153 |
+
if n.is_integer and n < 1:
|
154 |
+
raise ValueError("'n' must be positive integer")
|
155 |
+
if l.is_integer and not (n > l):
|
156 |
+
raise ValueError("'n' must be greater than 'l'")
|
157 |
+
if m.is_integer and not (abs(m) <= l):
|
158 |
+
raise ValueError("|'m'| must be less or equal 'l'")
|
159 |
+
# return the hydrogen wave function
|
160 |
+
return R_nl(n, l, r, Z)*Ynm(l, m, theta, phi).expand(func=True)
|
161 |
+
|
162 |
+
|
163 |
+
def E_nl(n, Z=1):
|
164 |
+
"""
|
165 |
+
Returns the energy of the state (n, l) in Hartree atomic units.
|
166 |
+
|
167 |
+
The energy does not depend on "l".
|
168 |
+
|
169 |
+
Parameters
|
170 |
+
==========
|
171 |
+
|
172 |
+
n : integer
|
173 |
+
Principal Quantum Number which is
|
174 |
+
an integer with possible values as 1, 2, 3, 4,...
|
175 |
+
Z :
|
176 |
+
Atomic number (1 for Hydrogen, 2 for Helium, ...)
|
177 |
+
|
178 |
+
Examples
|
179 |
+
========
|
180 |
+
|
181 |
+
>>> from sympy.physics.hydrogen import E_nl
|
182 |
+
>>> from sympy.abc import n, Z
|
183 |
+
>>> E_nl(n, Z)
|
184 |
+
-Z**2/(2*n**2)
|
185 |
+
>>> E_nl(1)
|
186 |
+
-1/2
|
187 |
+
>>> E_nl(2)
|
188 |
+
-1/8
|
189 |
+
>>> E_nl(3)
|
190 |
+
-1/18
|
191 |
+
>>> E_nl(3, 47)
|
192 |
+
-2209/18
|
193 |
+
|
194 |
+
"""
|
195 |
+
n, Z = S(n), S(Z)
|
196 |
+
if n.is_integer and (n < 1):
|
197 |
+
raise ValueError("'n' must be positive integer")
|
198 |
+
return -Z**2/(2*n**2)
|
199 |
+
|
200 |
+
|
201 |
+
def E_nl_dirac(n, l, spin_up=True, Z=1, c=Float("137.035999037")):
|
202 |
+
"""
|
203 |
+
Returns the relativistic energy of the state (n, l, spin) in Hartree atomic
|
204 |
+
units.
|
205 |
+
|
206 |
+
The energy is calculated from the Dirac equation. The rest mass energy is
|
207 |
+
*not* included.
|
208 |
+
|
209 |
+
Parameters
|
210 |
+
==========
|
211 |
+
|
212 |
+
n : integer
|
213 |
+
Principal Quantum Number which is
|
214 |
+
an integer with possible values as 1, 2, 3, 4,...
|
215 |
+
l : integer
|
216 |
+
``l`` is the Angular Momentum Quantum Number with
|
217 |
+
values ranging from 0 to ``n-1``.
|
218 |
+
spin_up :
|
219 |
+
True if the electron spin is up (default), otherwise down
|
220 |
+
Z :
|
221 |
+
Atomic number (1 for Hydrogen, 2 for Helium, ...)
|
222 |
+
c :
|
223 |
+
Speed of light in atomic units. Default value is 137.035999037,
|
224 |
+
taken from https://arxiv.org/abs/1012.3627
|
225 |
+
|
226 |
+
Examples
|
227 |
+
========
|
228 |
+
|
229 |
+
>>> from sympy.physics.hydrogen import E_nl_dirac
|
230 |
+
>>> E_nl_dirac(1, 0)
|
231 |
+
-0.500006656595360
|
232 |
+
|
233 |
+
>>> E_nl_dirac(2, 0)
|
234 |
+
-0.125002080189006
|
235 |
+
>>> E_nl_dirac(2, 1)
|
236 |
+
-0.125000416028342
|
237 |
+
>>> E_nl_dirac(2, 1, False)
|
238 |
+
-0.125002080189006
|
239 |
+
|
240 |
+
>>> E_nl_dirac(3, 0)
|
241 |
+
-0.0555562951740285
|
242 |
+
>>> E_nl_dirac(3, 1)
|
243 |
+
-0.0555558020932949
|
244 |
+
>>> E_nl_dirac(3, 1, False)
|
245 |
+
-0.0555562951740285
|
246 |
+
>>> E_nl_dirac(3, 2)
|
247 |
+
-0.0555556377366884
|
248 |
+
>>> E_nl_dirac(3, 2, False)
|
249 |
+
-0.0555558020932949
|
250 |
+
|
251 |
+
"""
|
252 |
+
n, l, Z, c = map(S, [n, l, Z, c])
|
253 |
+
if not (l >= 0):
|
254 |
+
raise ValueError("'l' must be positive or zero")
|
255 |
+
if not (n > l):
|
256 |
+
raise ValueError("'n' must be greater than 'l'")
|
257 |
+
if (l == 0 and spin_up is False):
|
258 |
+
raise ValueError("Spin must be up for l==0.")
|
259 |
+
# skappa is sign*kappa, where sign contains the correct sign
|
260 |
+
if spin_up:
|
261 |
+
skappa = -l - 1
|
262 |
+
else:
|
263 |
+
skappa = -l
|
264 |
+
beta = sqrt(skappa**2 - Z**2/c**2)
|
265 |
+
return c**2/sqrt(1 + Z**2/(n + skappa + beta)**2/c**2) - c**2
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/__init__.py
ADDED
@@ -0,0 +1,66 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
__all__ = [
|
2 |
+
'vector',
|
3 |
+
|
4 |
+
'CoordinateSym', 'ReferenceFrame', 'Dyadic', 'Vector', 'Point', 'cross',
|
5 |
+
'dot', 'express', 'time_derivative', 'outer', 'kinematic_equations',
|
6 |
+
'get_motion_params', 'partial_velocity', 'dynamicsymbols', 'vprint',
|
7 |
+
'vsstrrepr', 'vsprint', 'vpprint', 'vlatex', 'init_vprinting', 'curl',
|
8 |
+
'divergence', 'gradient', 'is_conservative', 'is_solenoidal',
|
9 |
+
'scalar_potential', 'scalar_potential_difference',
|
10 |
+
|
11 |
+
'KanesMethod',
|
12 |
+
|
13 |
+
'RigidBody',
|
14 |
+
|
15 |
+
'inertia', 'inertia_of_point_mass', 'linear_momentum', 'angular_momentum',
|
16 |
+
'kinetic_energy', 'potential_energy', 'Lagrangian', 'mechanics_printing',
|
17 |
+
'mprint', 'msprint', 'mpprint', 'mlatex', 'msubs', 'find_dynamicsymbols',
|
18 |
+
|
19 |
+
'Particle',
|
20 |
+
|
21 |
+
'LagrangesMethod',
|
22 |
+
|
23 |
+
'Linearizer',
|
24 |
+
|
25 |
+
'Body',
|
26 |
+
|
27 |
+
'SymbolicSystem',
|
28 |
+
|
29 |
+
'PinJoint', 'PrismaticJoint', 'CylindricalJoint', 'PlanarJoint',
|
30 |
+
'SphericalJoint', 'WeldJoint',
|
31 |
+
|
32 |
+
'JointsMethod'
|
33 |
+
]
|
34 |
+
|
35 |
+
from sympy.physics import vector
|
36 |
+
|
37 |
+
from sympy.physics.vector import (CoordinateSym, ReferenceFrame, Dyadic, Vector, Point,
|
38 |
+
cross, dot, express, time_derivative, outer, kinematic_equations,
|
39 |
+
get_motion_params, partial_velocity, dynamicsymbols, vprint,
|
40 |
+
vsstrrepr, vsprint, vpprint, vlatex, init_vprinting, curl, divergence,
|
41 |
+
gradient, is_conservative, is_solenoidal, scalar_potential,
|
42 |
+
scalar_potential_difference)
|
43 |
+
|
44 |
+
from .kane import KanesMethod
|
45 |
+
|
46 |
+
from .rigidbody import RigidBody
|
47 |
+
|
48 |
+
from .functions import (inertia, inertia_of_point_mass, linear_momentum,
|
49 |
+
angular_momentum, kinetic_energy, potential_energy, Lagrangian,
|
50 |
+
mechanics_printing, mprint, msprint, mpprint, mlatex, msubs,
|
51 |
+
find_dynamicsymbols)
|
52 |
+
|
53 |
+
from .particle import Particle
|
54 |
+
|
55 |
+
from .lagrange import LagrangesMethod
|
56 |
+
|
57 |
+
from .linearize import Linearizer
|
58 |
+
|
59 |
+
from .body import Body
|
60 |
+
|
61 |
+
from .system import SymbolicSystem
|
62 |
+
|
63 |
+
from .jointsmethod import JointsMethod
|
64 |
+
|
65 |
+
from .joint import (PinJoint, PrismaticJoint, CylindricalJoint, PlanarJoint,
|
66 |
+
SphericalJoint, WeldJoint)
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/body.py
ADDED
@@ -0,0 +1,611 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.core.backend import Symbol
|
2 |
+
from sympy.physics.vector import Point, Vector, ReferenceFrame, Dyadic
|
3 |
+
from sympy.physics.mechanics import RigidBody, Particle, inertia
|
4 |
+
|
5 |
+
__all__ = ['Body']
|
6 |
+
|
7 |
+
|
8 |
+
# XXX: We use type:ignore because the classes RigidBody and Particle have
|
9 |
+
# inconsistent parallel axis methods that take different numbers of arguments.
|
10 |
+
class Body(RigidBody, Particle): # type: ignore
|
11 |
+
"""
|
12 |
+
Body is a common representation of either a RigidBody or a Particle SymPy
|
13 |
+
object depending on what is passed in during initialization. If a mass is
|
14 |
+
passed in and central_inertia is left as None, the Particle object is
|
15 |
+
created. Otherwise a RigidBody object will be created.
|
16 |
+
|
17 |
+
Explanation
|
18 |
+
===========
|
19 |
+
|
20 |
+
The attributes that Body possesses will be the same as a Particle instance
|
21 |
+
or a Rigid Body instance depending on which was created. Additional
|
22 |
+
attributes are listed below.
|
23 |
+
|
24 |
+
Attributes
|
25 |
+
==========
|
26 |
+
|
27 |
+
name : string
|
28 |
+
The body's name
|
29 |
+
masscenter : Point
|
30 |
+
The point which represents the center of mass of the rigid body
|
31 |
+
frame : ReferenceFrame
|
32 |
+
The reference frame which the body is fixed in
|
33 |
+
mass : Sympifyable
|
34 |
+
The body's mass
|
35 |
+
inertia : (Dyadic, Point)
|
36 |
+
The body's inertia around its center of mass. This attribute is specific
|
37 |
+
to the rigid body form of Body and is left undefined for the Particle
|
38 |
+
form
|
39 |
+
loads : iterable
|
40 |
+
This list contains information on the different loads acting on the
|
41 |
+
Body. Forces are listed as a (point, vector) tuple and torques are
|
42 |
+
listed as (reference frame, vector) tuples.
|
43 |
+
|
44 |
+
Parameters
|
45 |
+
==========
|
46 |
+
|
47 |
+
name : String
|
48 |
+
Defines the name of the body. It is used as the base for defining
|
49 |
+
body specific properties.
|
50 |
+
masscenter : Point, optional
|
51 |
+
A point that represents the center of mass of the body or particle.
|
52 |
+
If no point is given, a point is generated.
|
53 |
+
mass : Sympifyable, optional
|
54 |
+
A Sympifyable object which represents the mass of the body. If no
|
55 |
+
mass is passed, one is generated.
|
56 |
+
frame : ReferenceFrame, optional
|
57 |
+
The ReferenceFrame that represents the reference frame of the body.
|
58 |
+
If no frame is given, a frame is generated.
|
59 |
+
central_inertia : Dyadic, optional
|
60 |
+
Central inertia dyadic of the body. If none is passed while creating
|
61 |
+
RigidBody, a default inertia is generated.
|
62 |
+
|
63 |
+
Examples
|
64 |
+
========
|
65 |
+
|
66 |
+
Default behaviour. This results in the creation of a RigidBody object for
|
67 |
+
which the mass, mass center, frame and inertia attributes are given default
|
68 |
+
values. ::
|
69 |
+
|
70 |
+
>>> from sympy.physics.mechanics import Body
|
71 |
+
>>> body = Body('name_of_body')
|
72 |
+
|
73 |
+
This next example demonstrates the code required to specify all of the
|
74 |
+
values of the Body object. Note this will also create a RigidBody version of
|
75 |
+
the Body object. ::
|
76 |
+
|
77 |
+
>>> from sympy import Symbol
|
78 |
+
>>> from sympy.physics.mechanics import ReferenceFrame, Point, inertia
|
79 |
+
>>> from sympy.physics.mechanics import Body
|
80 |
+
>>> mass = Symbol('mass')
|
81 |
+
>>> masscenter = Point('masscenter')
|
82 |
+
>>> frame = ReferenceFrame('frame')
|
83 |
+
>>> ixx = Symbol('ixx')
|
84 |
+
>>> body_inertia = inertia(frame, ixx, 0, 0)
|
85 |
+
>>> body = Body('name_of_body', masscenter, mass, frame, body_inertia)
|
86 |
+
|
87 |
+
The minimal code required to create a Particle version of the Body object
|
88 |
+
involves simply passing in a name and a mass. ::
|
89 |
+
|
90 |
+
>>> from sympy import Symbol
|
91 |
+
>>> from sympy.physics.mechanics import Body
|
92 |
+
>>> mass = Symbol('mass')
|
93 |
+
>>> body = Body('name_of_body', mass=mass)
|
94 |
+
|
95 |
+
The Particle version of the Body object can also receive a masscenter point
|
96 |
+
and a reference frame, just not an inertia.
|
97 |
+
"""
|
98 |
+
|
99 |
+
def __init__(self, name, masscenter=None, mass=None, frame=None,
|
100 |
+
central_inertia=None):
|
101 |
+
|
102 |
+
self.name = name
|
103 |
+
self._loads = []
|
104 |
+
|
105 |
+
if frame is None:
|
106 |
+
frame = ReferenceFrame(name + '_frame')
|
107 |
+
|
108 |
+
if masscenter is None:
|
109 |
+
masscenter = Point(name + '_masscenter')
|
110 |
+
|
111 |
+
if central_inertia is None and mass is None:
|
112 |
+
ixx = Symbol(name + '_ixx')
|
113 |
+
iyy = Symbol(name + '_iyy')
|
114 |
+
izz = Symbol(name + '_izz')
|
115 |
+
izx = Symbol(name + '_izx')
|
116 |
+
ixy = Symbol(name + '_ixy')
|
117 |
+
iyz = Symbol(name + '_iyz')
|
118 |
+
_inertia = (inertia(frame, ixx, iyy, izz, ixy, iyz, izx),
|
119 |
+
masscenter)
|
120 |
+
else:
|
121 |
+
_inertia = (central_inertia, masscenter)
|
122 |
+
|
123 |
+
if mass is None:
|
124 |
+
_mass = Symbol(name + '_mass')
|
125 |
+
else:
|
126 |
+
_mass = mass
|
127 |
+
|
128 |
+
masscenter.set_vel(frame, 0)
|
129 |
+
|
130 |
+
# If user passes masscenter and mass then a particle is created
|
131 |
+
# otherwise a rigidbody. As a result a body may or may not have inertia.
|
132 |
+
if central_inertia is None and mass is not None:
|
133 |
+
self.frame = frame
|
134 |
+
self.masscenter = masscenter
|
135 |
+
Particle.__init__(self, name, masscenter, _mass)
|
136 |
+
self._central_inertia = Dyadic(0)
|
137 |
+
else:
|
138 |
+
RigidBody.__init__(self, name, masscenter, frame, _mass, _inertia)
|
139 |
+
|
140 |
+
@property
|
141 |
+
def loads(self):
|
142 |
+
return self._loads
|
143 |
+
|
144 |
+
@property
|
145 |
+
def x(self):
|
146 |
+
"""The basis Vector for the Body, in the x direction."""
|
147 |
+
return self.frame.x
|
148 |
+
|
149 |
+
@property
|
150 |
+
def y(self):
|
151 |
+
"""The basis Vector for the Body, in the y direction."""
|
152 |
+
return self.frame.y
|
153 |
+
|
154 |
+
@property
|
155 |
+
def z(self):
|
156 |
+
"""The basis Vector for the Body, in the z direction."""
|
157 |
+
return self.frame.z
|
158 |
+
|
159 |
+
@property
|
160 |
+
def inertia(self):
|
161 |
+
"""The body's inertia about a point; stored as (Dyadic, Point)."""
|
162 |
+
if self.is_rigidbody:
|
163 |
+
return RigidBody.inertia.fget(self)
|
164 |
+
return (self.central_inertia, self.masscenter)
|
165 |
+
|
166 |
+
@inertia.setter
|
167 |
+
def inertia(self, I):
|
168 |
+
RigidBody.inertia.fset(self, I)
|
169 |
+
|
170 |
+
@property
|
171 |
+
def is_rigidbody(self):
|
172 |
+
if hasattr(self, '_inertia'):
|
173 |
+
return True
|
174 |
+
return False
|
175 |
+
|
176 |
+
def kinetic_energy(self, frame):
|
177 |
+
"""Kinetic energy of the body.
|
178 |
+
|
179 |
+
Parameters
|
180 |
+
==========
|
181 |
+
|
182 |
+
frame : ReferenceFrame or Body
|
183 |
+
The Body's angular velocity and the velocity of it's mass
|
184 |
+
center are typically defined with respect to an inertial frame but
|
185 |
+
any relevant frame in which the velocities are known can be supplied.
|
186 |
+
|
187 |
+
Examples
|
188 |
+
========
|
189 |
+
|
190 |
+
>>> from sympy.physics.mechanics import Body, ReferenceFrame, Point
|
191 |
+
>>> from sympy import symbols
|
192 |
+
>>> m, v, r, omega = symbols('m v r omega')
|
193 |
+
>>> N = ReferenceFrame('N')
|
194 |
+
>>> O = Point('O')
|
195 |
+
>>> P = Body('P', masscenter=O, mass=m)
|
196 |
+
>>> P.masscenter.set_vel(N, v * N.y)
|
197 |
+
>>> P.kinetic_energy(N)
|
198 |
+
m*v**2/2
|
199 |
+
|
200 |
+
>>> N = ReferenceFrame('N')
|
201 |
+
>>> b = ReferenceFrame('b')
|
202 |
+
>>> b.set_ang_vel(N, omega * b.x)
|
203 |
+
>>> P = Point('P')
|
204 |
+
>>> P.set_vel(N, v * N.x)
|
205 |
+
>>> B = Body('B', masscenter=P, frame=b)
|
206 |
+
>>> B.kinetic_energy(N)
|
207 |
+
B_ixx*omega**2/2 + B_mass*v**2/2
|
208 |
+
|
209 |
+
See Also
|
210 |
+
========
|
211 |
+
|
212 |
+
sympy.physics.mechanics : Particle, RigidBody
|
213 |
+
|
214 |
+
"""
|
215 |
+
if isinstance(frame, Body):
|
216 |
+
frame = Body.frame
|
217 |
+
if self.is_rigidbody:
|
218 |
+
return RigidBody(self.name, self.masscenter, self.frame, self.mass,
|
219 |
+
(self.central_inertia, self.masscenter)).kinetic_energy(frame)
|
220 |
+
return Particle(self.name, self.masscenter, self.mass).kinetic_energy(frame)
|
221 |
+
|
222 |
+
def apply_force(self, force, point=None, reaction_body=None, reaction_point=None):
|
223 |
+
"""Add force to the body(s).
|
224 |
+
|
225 |
+
Explanation
|
226 |
+
===========
|
227 |
+
|
228 |
+
Applies the force on self or equal and oppposite forces on
|
229 |
+
self and other body if both are given on the desried point on the bodies.
|
230 |
+
The force applied on other body is taken opposite of self, i.e, -force.
|
231 |
+
|
232 |
+
Parameters
|
233 |
+
==========
|
234 |
+
|
235 |
+
force: Vector
|
236 |
+
The force to be applied.
|
237 |
+
point: Point, optional
|
238 |
+
The point on self on which force is applied.
|
239 |
+
By default self's masscenter.
|
240 |
+
reaction_body: Body, optional
|
241 |
+
Second body on which equal and opposite force
|
242 |
+
is to be applied.
|
243 |
+
reaction_point : Point, optional
|
244 |
+
The point on other body on which equal and opposite
|
245 |
+
force is applied. By default masscenter of other body.
|
246 |
+
|
247 |
+
Example
|
248 |
+
=======
|
249 |
+
|
250 |
+
>>> from sympy import symbols
|
251 |
+
>>> from sympy.physics.mechanics import Body, Point, dynamicsymbols
|
252 |
+
>>> m, g = symbols('m g')
|
253 |
+
>>> B = Body('B')
|
254 |
+
>>> force1 = m*g*B.z
|
255 |
+
>>> B.apply_force(force1) #Applying force on B's masscenter
|
256 |
+
>>> B.loads
|
257 |
+
[(B_masscenter, g*m*B_frame.z)]
|
258 |
+
|
259 |
+
We can also remove some part of force from any point on the body by
|
260 |
+
adding the opposite force to the body on that point.
|
261 |
+
|
262 |
+
>>> f1, f2 = dynamicsymbols('f1 f2')
|
263 |
+
>>> P = Point('P') #Considering point P on body B
|
264 |
+
>>> B.apply_force(f1*B.x + f2*B.y, P)
|
265 |
+
>>> B.loads
|
266 |
+
[(B_masscenter, g*m*B_frame.z), (P, f1(t)*B_frame.x + f2(t)*B_frame.y)]
|
267 |
+
|
268 |
+
Let's remove f1 from point P on body B.
|
269 |
+
|
270 |
+
>>> B.apply_force(-f1*B.x, P)
|
271 |
+
>>> B.loads
|
272 |
+
[(B_masscenter, g*m*B_frame.z), (P, f2(t)*B_frame.y)]
|
273 |
+
|
274 |
+
To further demonstrate the use of ``apply_force`` attribute,
|
275 |
+
consider two bodies connected through a spring.
|
276 |
+
|
277 |
+
>>> from sympy.physics.mechanics import Body, dynamicsymbols
|
278 |
+
>>> N = Body('N') #Newtonion Frame
|
279 |
+
>>> x = dynamicsymbols('x')
|
280 |
+
>>> B1 = Body('B1')
|
281 |
+
>>> B2 = Body('B2')
|
282 |
+
>>> spring_force = x*N.x
|
283 |
+
|
284 |
+
Now let's apply equal and opposite spring force to the bodies.
|
285 |
+
|
286 |
+
>>> P1 = Point('P1')
|
287 |
+
>>> P2 = Point('P2')
|
288 |
+
>>> B1.apply_force(spring_force, point=P1, reaction_body=B2, reaction_point=P2)
|
289 |
+
|
290 |
+
We can check the loads(forces) applied to bodies now.
|
291 |
+
|
292 |
+
>>> B1.loads
|
293 |
+
[(P1, x(t)*N_frame.x)]
|
294 |
+
>>> B2.loads
|
295 |
+
[(P2, - x(t)*N_frame.x)]
|
296 |
+
|
297 |
+
Notes
|
298 |
+
=====
|
299 |
+
|
300 |
+
If a new force is applied to a body on a point which already has some
|
301 |
+
force applied on it, then the new force is added to the already applied
|
302 |
+
force on that point.
|
303 |
+
|
304 |
+
"""
|
305 |
+
|
306 |
+
if not isinstance(point, Point):
|
307 |
+
if point is None:
|
308 |
+
point = self.masscenter # masscenter
|
309 |
+
else:
|
310 |
+
raise TypeError("Force must be applied to a point on the body.")
|
311 |
+
if not isinstance(force, Vector):
|
312 |
+
raise TypeError("Force must be a vector.")
|
313 |
+
|
314 |
+
if reaction_body is not None:
|
315 |
+
reaction_body.apply_force(-force, point=reaction_point)
|
316 |
+
|
317 |
+
for load in self._loads:
|
318 |
+
if point in load:
|
319 |
+
force += load[1]
|
320 |
+
self._loads.remove(load)
|
321 |
+
break
|
322 |
+
|
323 |
+
self._loads.append((point, force))
|
324 |
+
|
325 |
+
def apply_torque(self, torque, reaction_body=None):
|
326 |
+
"""Add torque to the body(s).
|
327 |
+
|
328 |
+
Explanation
|
329 |
+
===========
|
330 |
+
|
331 |
+
Applies the torque on self or equal and oppposite torquess on
|
332 |
+
self and other body if both are given.
|
333 |
+
The torque applied on other body is taken opposite of self,
|
334 |
+
i.e, -torque.
|
335 |
+
|
336 |
+
Parameters
|
337 |
+
==========
|
338 |
+
|
339 |
+
torque: Vector
|
340 |
+
The torque to be applied.
|
341 |
+
reaction_body: Body, optional
|
342 |
+
Second body on which equal and opposite torque
|
343 |
+
is to be applied.
|
344 |
+
|
345 |
+
Example
|
346 |
+
=======
|
347 |
+
|
348 |
+
>>> from sympy import symbols
|
349 |
+
>>> from sympy.physics.mechanics import Body, dynamicsymbols
|
350 |
+
>>> t = symbols('t')
|
351 |
+
>>> B = Body('B')
|
352 |
+
>>> torque1 = t*B.z
|
353 |
+
>>> B.apply_torque(torque1)
|
354 |
+
>>> B.loads
|
355 |
+
[(B_frame, t*B_frame.z)]
|
356 |
+
|
357 |
+
We can also remove some part of torque from the body by
|
358 |
+
adding the opposite torque to the body.
|
359 |
+
|
360 |
+
>>> t1, t2 = dynamicsymbols('t1 t2')
|
361 |
+
>>> B.apply_torque(t1*B.x + t2*B.y)
|
362 |
+
>>> B.loads
|
363 |
+
[(B_frame, t1(t)*B_frame.x + t2(t)*B_frame.y + t*B_frame.z)]
|
364 |
+
|
365 |
+
Let's remove t1 from Body B.
|
366 |
+
|
367 |
+
>>> B.apply_torque(-t1*B.x)
|
368 |
+
>>> B.loads
|
369 |
+
[(B_frame, t2(t)*B_frame.y + t*B_frame.z)]
|
370 |
+
|
371 |
+
To further demonstrate the use, let us consider two bodies such that
|
372 |
+
a torque `T` is acting on one body, and `-T` on the other.
|
373 |
+
|
374 |
+
>>> from sympy.physics.mechanics import Body, dynamicsymbols
|
375 |
+
>>> N = Body('N') #Newtonion frame
|
376 |
+
>>> B1 = Body('B1')
|
377 |
+
>>> B2 = Body('B2')
|
378 |
+
>>> v = dynamicsymbols('v')
|
379 |
+
>>> T = v*N.y #Torque
|
380 |
+
|
381 |
+
Now let's apply equal and opposite torque to the bodies.
|
382 |
+
|
383 |
+
>>> B1.apply_torque(T, B2)
|
384 |
+
|
385 |
+
We can check the loads (torques) applied to bodies now.
|
386 |
+
|
387 |
+
>>> B1.loads
|
388 |
+
[(B1_frame, v(t)*N_frame.y)]
|
389 |
+
>>> B2.loads
|
390 |
+
[(B2_frame, - v(t)*N_frame.y)]
|
391 |
+
|
392 |
+
Notes
|
393 |
+
=====
|
394 |
+
|
395 |
+
If a new torque is applied on body which already has some torque applied on it,
|
396 |
+
then the new torque is added to the previous torque about the body's frame.
|
397 |
+
|
398 |
+
"""
|
399 |
+
|
400 |
+
if not isinstance(torque, Vector):
|
401 |
+
raise TypeError("A Vector must be supplied to add torque.")
|
402 |
+
|
403 |
+
if reaction_body is not None:
|
404 |
+
reaction_body.apply_torque(-torque)
|
405 |
+
|
406 |
+
for load in self._loads:
|
407 |
+
if self.frame in load:
|
408 |
+
torque += load[1]
|
409 |
+
self._loads.remove(load)
|
410 |
+
break
|
411 |
+
self._loads.append((self.frame, torque))
|
412 |
+
|
413 |
+
def clear_loads(self):
|
414 |
+
"""
|
415 |
+
Clears the Body's loads list.
|
416 |
+
|
417 |
+
Example
|
418 |
+
=======
|
419 |
+
|
420 |
+
>>> from sympy.physics.mechanics import Body
|
421 |
+
>>> B = Body('B')
|
422 |
+
>>> force = B.x + B.y
|
423 |
+
>>> B.apply_force(force)
|
424 |
+
>>> B.loads
|
425 |
+
[(B_masscenter, B_frame.x + B_frame.y)]
|
426 |
+
>>> B.clear_loads()
|
427 |
+
>>> B.loads
|
428 |
+
[]
|
429 |
+
|
430 |
+
"""
|
431 |
+
|
432 |
+
self._loads = []
|
433 |
+
|
434 |
+
def remove_load(self, about=None):
|
435 |
+
"""
|
436 |
+
Remove load about a point or frame.
|
437 |
+
|
438 |
+
Parameters
|
439 |
+
==========
|
440 |
+
|
441 |
+
about : Point or ReferenceFrame, optional
|
442 |
+
The point about which force is applied,
|
443 |
+
and is to be removed.
|
444 |
+
If about is None, then the torque about
|
445 |
+
self's frame is removed.
|
446 |
+
|
447 |
+
Example
|
448 |
+
=======
|
449 |
+
|
450 |
+
>>> from sympy.physics.mechanics import Body, Point
|
451 |
+
>>> B = Body('B')
|
452 |
+
>>> P = Point('P')
|
453 |
+
>>> f1 = B.x
|
454 |
+
>>> f2 = B.y
|
455 |
+
>>> B.apply_force(f1)
|
456 |
+
>>> B.apply_force(f2, P)
|
457 |
+
>>> B.loads
|
458 |
+
[(B_masscenter, B_frame.x), (P, B_frame.y)]
|
459 |
+
|
460 |
+
>>> B.remove_load(P)
|
461 |
+
>>> B.loads
|
462 |
+
[(B_masscenter, B_frame.x)]
|
463 |
+
|
464 |
+
"""
|
465 |
+
|
466 |
+
if about is not None:
|
467 |
+
if not isinstance(about, Point):
|
468 |
+
raise TypeError('Load is applied about Point or ReferenceFrame.')
|
469 |
+
else:
|
470 |
+
about = self.frame
|
471 |
+
|
472 |
+
for load in self._loads:
|
473 |
+
if about in load:
|
474 |
+
self._loads.remove(load)
|
475 |
+
break
|
476 |
+
|
477 |
+
def masscenter_vel(self, body):
|
478 |
+
"""
|
479 |
+
Returns the velocity of the mass center with respect to the provided
|
480 |
+
rigid body or reference frame.
|
481 |
+
|
482 |
+
Parameters
|
483 |
+
==========
|
484 |
+
|
485 |
+
body: Body or ReferenceFrame
|
486 |
+
The rigid body or reference frame to calculate the velocity in.
|
487 |
+
|
488 |
+
Example
|
489 |
+
=======
|
490 |
+
|
491 |
+
>>> from sympy.physics.mechanics import Body
|
492 |
+
>>> A = Body('A')
|
493 |
+
>>> B = Body('B')
|
494 |
+
>>> A.masscenter.set_vel(B.frame, 5*B.frame.x)
|
495 |
+
>>> A.masscenter_vel(B)
|
496 |
+
5*B_frame.x
|
497 |
+
>>> A.masscenter_vel(B.frame)
|
498 |
+
5*B_frame.x
|
499 |
+
|
500 |
+
"""
|
501 |
+
|
502 |
+
if isinstance(body, ReferenceFrame):
|
503 |
+
frame=body
|
504 |
+
elif isinstance(body, Body):
|
505 |
+
frame = body.frame
|
506 |
+
return self.masscenter.vel(frame)
|
507 |
+
|
508 |
+
def ang_vel_in(self, body):
|
509 |
+
"""
|
510 |
+
Returns this body's angular velocity with respect to the provided
|
511 |
+
rigid body or reference frame.
|
512 |
+
|
513 |
+
Parameters
|
514 |
+
==========
|
515 |
+
|
516 |
+
body: Body or ReferenceFrame
|
517 |
+
The rigid body or reference frame to calculate the angular velocity in.
|
518 |
+
|
519 |
+
Example
|
520 |
+
=======
|
521 |
+
|
522 |
+
>>> from sympy.physics.mechanics import Body, ReferenceFrame
|
523 |
+
>>> A = Body('A')
|
524 |
+
>>> N = ReferenceFrame('N')
|
525 |
+
>>> B = Body('B', frame=N)
|
526 |
+
>>> A.frame.set_ang_vel(N, 5*N.x)
|
527 |
+
>>> A.ang_vel_in(B)
|
528 |
+
5*N.x
|
529 |
+
>>> A.ang_vel_in(N)
|
530 |
+
5*N.x
|
531 |
+
|
532 |
+
"""
|
533 |
+
|
534 |
+
if isinstance(body, ReferenceFrame):
|
535 |
+
frame=body
|
536 |
+
elif isinstance(body, Body):
|
537 |
+
frame = body.frame
|
538 |
+
return self.frame.ang_vel_in(frame)
|
539 |
+
|
540 |
+
def dcm(self, body):
|
541 |
+
"""
|
542 |
+
Returns the direction cosine matrix of this body relative to the
|
543 |
+
provided rigid body or reference frame.
|
544 |
+
|
545 |
+
Parameters
|
546 |
+
==========
|
547 |
+
|
548 |
+
body: Body or ReferenceFrame
|
549 |
+
The rigid body or reference frame to calculate the dcm.
|
550 |
+
|
551 |
+
Example
|
552 |
+
=======
|
553 |
+
|
554 |
+
>>> from sympy.physics.mechanics import Body
|
555 |
+
>>> A = Body('A')
|
556 |
+
>>> B = Body('B')
|
557 |
+
>>> A.frame.orient_axis(B.frame, B.frame.x, 5)
|
558 |
+
>>> A.dcm(B)
|
559 |
+
Matrix([
|
560 |
+
[1, 0, 0],
|
561 |
+
[0, cos(5), sin(5)],
|
562 |
+
[0, -sin(5), cos(5)]])
|
563 |
+
>>> A.dcm(B.frame)
|
564 |
+
Matrix([
|
565 |
+
[1, 0, 0],
|
566 |
+
[0, cos(5), sin(5)],
|
567 |
+
[0, -sin(5), cos(5)]])
|
568 |
+
|
569 |
+
"""
|
570 |
+
|
571 |
+
if isinstance(body, ReferenceFrame):
|
572 |
+
frame=body
|
573 |
+
elif isinstance(body, Body):
|
574 |
+
frame = body.frame
|
575 |
+
return self.frame.dcm(frame)
|
576 |
+
|
577 |
+
def parallel_axis(self, point, frame=None):
|
578 |
+
"""Returns the inertia dyadic of the body with respect to another
|
579 |
+
point.
|
580 |
+
|
581 |
+
Parameters
|
582 |
+
==========
|
583 |
+
|
584 |
+
point : sympy.physics.vector.Point
|
585 |
+
The point to express the inertia dyadic about.
|
586 |
+
frame : sympy.physics.vector.ReferenceFrame
|
587 |
+
The reference frame used to construct the dyadic.
|
588 |
+
|
589 |
+
Returns
|
590 |
+
=======
|
591 |
+
|
592 |
+
inertia : sympy.physics.vector.Dyadic
|
593 |
+
The inertia dyadic of the rigid body expressed about the provided
|
594 |
+
point.
|
595 |
+
|
596 |
+
Example
|
597 |
+
=======
|
598 |
+
|
599 |
+
>>> from sympy.physics.mechanics import Body
|
600 |
+
>>> A = Body('A')
|
601 |
+
>>> P = A.masscenter.locatenew('point', 3 * A.x + 5 * A.y)
|
602 |
+
>>> A.parallel_axis(P).to_matrix(A.frame)
|
603 |
+
Matrix([
|
604 |
+
[A_ixx + 25*A_mass, A_ixy - 15*A_mass, A_izx],
|
605 |
+
[A_ixy - 15*A_mass, A_iyy + 9*A_mass, A_iyz],
|
606 |
+
[ A_izx, A_iyz, A_izz + 34*A_mass]])
|
607 |
+
|
608 |
+
"""
|
609 |
+
if self.is_rigidbody:
|
610 |
+
return RigidBody.parallel_axis(self, point, frame)
|
611 |
+
return Particle.parallel_axis(self, point, frame)
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/functions.py
ADDED
@@ -0,0 +1,779 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.utilities import dict_merge
|
2 |
+
from sympy.utilities.iterables import iterable
|
3 |
+
from sympy.physics.vector import (Dyadic, Vector, ReferenceFrame,
|
4 |
+
Point, dynamicsymbols)
|
5 |
+
from sympy.physics.vector.printing import (vprint, vsprint, vpprint, vlatex,
|
6 |
+
init_vprinting)
|
7 |
+
from sympy.physics.mechanics.particle import Particle
|
8 |
+
from sympy.physics.mechanics.rigidbody import RigidBody
|
9 |
+
from sympy.simplify.simplify import simplify
|
10 |
+
from sympy.core.backend import (Matrix, sympify, Mul, Derivative, sin, cos,
|
11 |
+
tan, AppliedUndef, S)
|
12 |
+
|
13 |
+
__all__ = ['inertia',
|
14 |
+
'inertia_of_point_mass',
|
15 |
+
'linear_momentum',
|
16 |
+
'angular_momentum',
|
17 |
+
'kinetic_energy',
|
18 |
+
'potential_energy',
|
19 |
+
'Lagrangian',
|
20 |
+
'mechanics_printing',
|
21 |
+
'mprint',
|
22 |
+
'msprint',
|
23 |
+
'mpprint',
|
24 |
+
'mlatex',
|
25 |
+
'msubs',
|
26 |
+
'find_dynamicsymbols']
|
27 |
+
|
28 |
+
# These are functions that we've moved and renamed during extracting the
|
29 |
+
# basic vector calculus code from the mechanics packages.
|
30 |
+
|
31 |
+
mprint = vprint
|
32 |
+
msprint = vsprint
|
33 |
+
mpprint = vpprint
|
34 |
+
mlatex = vlatex
|
35 |
+
|
36 |
+
|
37 |
+
def mechanics_printing(**kwargs):
|
38 |
+
"""
|
39 |
+
Initializes time derivative printing for all SymPy objects in
|
40 |
+
mechanics module.
|
41 |
+
"""
|
42 |
+
|
43 |
+
init_vprinting(**kwargs)
|
44 |
+
|
45 |
+
mechanics_printing.__doc__ = init_vprinting.__doc__
|
46 |
+
|
47 |
+
|
48 |
+
def inertia(frame, ixx, iyy, izz, ixy=0, iyz=0, izx=0):
|
49 |
+
"""Simple way to create inertia Dyadic object.
|
50 |
+
|
51 |
+
Explanation
|
52 |
+
===========
|
53 |
+
|
54 |
+
If you do not know what a Dyadic is, just treat this like the inertia
|
55 |
+
tensor. Then, do the easy thing and define it in a body-fixed frame.
|
56 |
+
|
57 |
+
Parameters
|
58 |
+
==========
|
59 |
+
|
60 |
+
frame : ReferenceFrame
|
61 |
+
The frame the inertia is defined in
|
62 |
+
ixx : Sympifyable
|
63 |
+
the xx element in the inertia dyadic
|
64 |
+
iyy : Sympifyable
|
65 |
+
the yy element in the inertia dyadic
|
66 |
+
izz : Sympifyable
|
67 |
+
the zz element in the inertia dyadic
|
68 |
+
ixy : Sympifyable
|
69 |
+
the xy element in the inertia dyadic
|
70 |
+
iyz : Sympifyable
|
71 |
+
the yz element in the inertia dyadic
|
72 |
+
izx : Sympifyable
|
73 |
+
the zx element in the inertia dyadic
|
74 |
+
|
75 |
+
Examples
|
76 |
+
========
|
77 |
+
|
78 |
+
>>> from sympy.physics.mechanics import ReferenceFrame, inertia
|
79 |
+
>>> N = ReferenceFrame('N')
|
80 |
+
>>> inertia(N, 1, 2, 3)
|
81 |
+
(N.x|N.x) + 2*(N.y|N.y) + 3*(N.z|N.z)
|
82 |
+
|
83 |
+
"""
|
84 |
+
|
85 |
+
if not isinstance(frame, ReferenceFrame):
|
86 |
+
raise TypeError('Need to define the inertia in a frame')
|
87 |
+
ixx = sympify(ixx)
|
88 |
+
ixy = sympify(ixy)
|
89 |
+
iyy = sympify(iyy)
|
90 |
+
iyz = sympify(iyz)
|
91 |
+
izx = sympify(izx)
|
92 |
+
izz = sympify(izz)
|
93 |
+
ol = ixx * (frame.x | frame.x)
|
94 |
+
ol += ixy * (frame.x | frame.y)
|
95 |
+
ol += izx * (frame.x | frame.z)
|
96 |
+
ol += ixy * (frame.y | frame.x)
|
97 |
+
ol += iyy * (frame.y | frame.y)
|
98 |
+
ol += iyz * (frame.y | frame.z)
|
99 |
+
ol += izx * (frame.z | frame.x)
|
100 |
+
ol += iyz * (frame.z | frame.y)
|
101 |
+
ol += izz * (frame.z | frame.z)
|
102 |
+
return ol
|
103 |
+
|
104 |
+
|
105 |
+
def inertia_of_point_mass(mass, pos_vec, frame):
|
106 |
+
"""Inertia dyadic of a point mass relative to point O.
|
107 |
+
|
108 |
+
Parameters
|
109 |
+
==========
|
110 |
+
|
111 |
+
mass : Sympifyable
|
112 |
+
Mass of the point mass
|
113 |
+
pos_vec : Vector
|
114 |
+
Position from point O to point mass
|
115 |
+
frame : ReferenceFrame
|
116 |
+
Reference frame to express the dyadic in
|
117 |
+
|
118 |
+
Examples
|
119 |
+
========
|
120 |
+
|
121 |
+
>>> from sympy import symbols
|
122 |
+
>>> from sympy.physics.mechanics import ReferenceFrame, inertia_of_point_mass
|
123 |
+
>>> N = ReferenceFrame('N')
|
124 |
+
>>> r, m = symbols('r m')
|
125 |
+
>>> px = r * N.x
|
126 |
+
>>> inertia_of_point_mass(m, px, N)
|
127 |
+
m*r**2*(N.y|N.y) + m*r**2*(N.z|N.z)
|
128 |
+
|
129 |
+
"""
|
130 |
+
|
131 |
+
return mass * (((frame.x | frame.x) + (frame.y | frame.y) +
|
132 |
+
(frame.z | frame.z)) * (pos_vec & pos_vec) -
|
133 |
+
(pos_vec | pos_vec))
|
134 |
+
|
135 |
+
|
136 |
+
def linear_momentum(frame, *body):
|
137 |
+
"""Linear momentum of the system.
|
138 |
+
|
139 |
+
Explanation
|
140 |
+
===========
|
141 |
+
|
142 |
+
This function returns the linear momentum of a system of Particle's and/or
|
143 |
+
RigidBody's. The linear momentum of a system is equal to the vector sum of
|
144 |
+
the linear momentum of its constituents. Consider a system, S, comprised of
|
145 |
+
a rigid body, A, and a particle, P. The linear momentum of the system, L,
|
146 |
+
is equal to the vector sum of the linear momentum of the particle, L1, and
|
147 |
+
the linear momentum of the rigid body, L2, i.e.
|
148 |
+
|
149 |
+
L = L1 + L2
|
150 |
+
|
151 |
+
Parameters
|
152 |
+
==========
|
153 |
+
|
154 |
+
frame : ReferenceFrame
|
155 |
+
The frame in which linear momentum is desired.
|
156 |
+
body1, body2, body3... : Particle and/or RigidBody
|
157 |
+
The body (or bodies) whose linear momentum is required.
|
158 |
+
|
159 |
+
Examples
|
160 |
+
========
|
161 |
+
|
162 |
+
>>> from sympy.physics.mechanics import Point, Particle, ReferenceFrame
|
163 |
+
>>> from sympy.physics.mechanics import RigidBody, outer, linear_momentum
|
164 |
+
>>> N = ReferenceFrame('N')
|
165 |
+
>>> P = Point('P')
|
166 |
+
>>> P.set_vel(N, 10 * N.x)
|
167 |
+
>>> Pa = Particle('Pa', P, 1)
|
168 |
+
>>> Ac = Point('Ac')
|
169 |
+
>>> Ac.set_vel(N, 25 * N.y)
|
170 |
+
>>> I = outer(N.x, N.x)
|
171 |
+
>>> A = RigidBody('A', Ac, N, 20, (I, Ac))
|
172 |
+
>>> linear_momentum(N, A, Pa)
|
173 |
+
10*N.x + 500*N.y
|
174 |
+
|
175 |
+
"""
|
176 |
+
|
177 |
+
if not isinstance(frame, ReferenceFrame):
|
178 |
+
raise TypeError('Please specify a valid ReferenceFrame')
|
179 |
+
else:
|
180 |
+
linear_momentum_sys = Vector(0)
|
181 |
+
for e in body:
|
182 |
+
if isinstance(e, (RigidBody, Particle)):
|
183 |
+
linear_momentum_sys += e.linear_momentum(frame)
|
184 |
+
else:
|
185 |
+
raise TypeError('*body must have only Particle or RigidBody')
|
186 |
+
return linear_momentum_sys
|
187 |
+
|
188 |
+
|
189 |
+
def angular_momentum(point, frame, *body):
|
190 |
+
"""Angular momentum of a system.
|
191 |
+
|
192 |
+
Explanation
|
193 |
+
===========
|
194 |
+
|
195 |
+
This function returns the angular momentum of a system of Particle's and/or
|
196 |
+
RigidBody's. The angular momentum of such a system is equal to the vector
|
197 |
+
sum of the angular momentum of its constituents. Consider a system, S,
|
198 |
+
comprised of a rigid body, A, and a particle, P. The angular momentum of
|
199 |
+
the system, H, is equal to the vector sum of the angular momentum of the
|
200 |
+
particle, H1, and the angular momentum of the rigid body, H2, i.e.
|
201 |
+
|
202 |
+
H = H1 + H2
|
203 |
+
|
204 |
+
Parameters
|
205 |
+
==========
|
206 |
+
|
207 |
+
point : Point
|
208 |
+
The point about which angular momentum of the system is desired.
|
209 |
+
frame : ReferenceFrame
|
210 |
+
The frame in which angular momentum is desired.
|
211 |
+
body1, body2, body3... : Particle and/or RigidBody
|
212 |
+
The body (or bodies) whose angular momentum is required.
|
213 |
+
|
214 |
+
Examples
|
215 |
+
========
|
216 |
+
|
217 |
+
>>> from sympy.physics.mechanics import Point, Particle, ReferenceFrame
|
218 |
+
>>> from sympy.physics.mechanics import RigidBody, outer, angular_momentum
|
219 |
+
>>> N = ReferenceFrame('N')
|
220 |
+
>>> O = Point('O')
|
221 |
+
>>> O.set_vel(N, 0 * N.x)
|
222 |
+
>>> P = O.locatenew('P', 1 * N.x)
|
223 |
+
>>> P.set_vel(N, 10 * N.x)
|
224 |
+
>>> Pa = Particle('Pa', P, 1)
|
225 |
+
>>> Ac = O.locatenew('Ac', 2 * N.y)
|
226 |
+
>>> Ac.set_vel(N, 5 * N.y)
|
227 |
+
>>> a = ReferenceFrame('a')
|
228 |
+
>>> a.set_ang_vel(N, 10 * N.z)
|
229 |
+
>>> I = outer(N.z, N.z)
|
230 |
+
>>> A = RigidBody('A', Ac, a, 20, (I, Ac))
|
231 |
+
>>> angular_momentum(O, N, Pa, A)
|
232 |
+
10*N.z
|
233 |
+
|
234 |
+
"""
|
235 |
+
|
236 |
+
if not isinstance(frame, ReferenceFrame):
|
237 |
+
raise TypeError('Please enter a valid ReferenceFrame')
|
238 |
+
if not isinstance(point, Point):
|
239 |
+
raise TypeError('Please specify a valid Point')
|
240 |
+
else:
|
241 |
+
angular_momentum_sys = Vector(0)
|
242 |
+
for e in body:
|
243 |
+
if isinstance(e, (RigidBody, Particle)):
|
244 |
+
angular_momentum_sys += e.angular_momentum(point, frame)
|
245 |
+
else:
|
246 |
+
raise TypeError('*body must have only Particle or RigidBody')
|
247 |
+
return angular_momentum_sys
|
248 |
+
|
249 |
+
|
250 |
+
def kinetic_energy(frame, *body):
|
251 |
+
"""Kinetic energy of a multibody system.
|
252 |
+
|
253 |
+
Explanation
|
254 |
+
===========
|
255 |
+
|
256 |
+
This function returns the kinetic energy of a system of Particle's and/or
|
257 |
+
RigidBody's. The kinetic energy of such a system is equal to the sum of
|
258 |
+
the kinetic energies of its constituents. Consider a system, S, comprising
|
259 |
+
a rigid body, A, and a particle, P. The kinetic energy of the system, T,
|
260 |
+
is equal to the vector sum of the kinetic energy of the particle, T1, and
|
261 |
+
the kinetic energy of the rigid body, T2, i.e.
|
262 |
+
|
263 |
+
T = T1 + T2
|
264 |
+
|
265 |
+
Kinetic energy is a scalar.
|
266 |
+
|
267 |
+
Parameters
|
268 |
+
==========
|
269 |
+
|
270 |
+
frame : ReferenceFrame
|
271 |
+
The frame in which the velocity or angular velocity of the body is
|
272 |
+
defined.
|
273 |
+
body1, body2, body3... : Particle and/or RigidBody
|
274 |
+
The body (or bodies) whose kinetic energy is required.
|
275 |
+
|
276 |
+
Examples
|
277 |
+
========
|
278 |
+
|
279 |
+
>>> from sympy.physics.mechanics import Point, Particle, ReferenceFrame
|
280 |
+
>>> from sympy.physics.mechanics import RigidBody, outer, kinetic_energy
|
281 |
+
>>> N = ReferenceFrame('N')
|
282 |
+
>>> O = Point('O')
|
283 |
+
>>> O.set_vel(N, 0 * N.x)
|
284 |
+
>>> P = O.locatenew('P', 1 * N.x)
|
285 |
+
>>> P.set_vel(N, 10 * N.x)
|
286 |
+
>>> Pa = Particle('Pa', P, 1)
|
287 |
+
>>> Ac = O.locatenew('Ac', 2 * N.y)
|
288 |
+
>>> Ac.set_vel(N, 5 * N.y)
|
289 |
+
>>> a = ReferenceFrame('a')
|
290 |
+
>>> a.set_ang_vel(N, 10 * N.z)
|
291 |
+
>>> I = outer(N.z, N.z)
|
292 |
+
>>> A = RigidBody('A', Ac, a, 20, (I, Ac))
|
293 |
+
>>> kinetic_energy(N, Pa, A)
|
294 |
+
350
|
295 |
+
|
296 |
+
"""
|
297 |
+
|
298 |
+
if not isinstance(frame, ReferenceFrame):
|
299 |
+
raise TypeError('Please enter a valid ReferenceFrame')
|
300 |
+
ke_sys = S.Zero
|
301 |
+
for e in body:
|
302 |
+
if isinstance(e, (RigidBody, Particle)):
|
303 |
+
ke_sys += e.kinetic_energy(frame)
|
304 |
+
else:
|
305 |
+
raise TypeError('*body must have only Particle or RigidBody')
|
306 |
+
return ke_sys
|
307 |
+
|
308 |
+
|
309 |
+
def potential_energy(*body):
|
310 |
+
"""Potential energy of a multibody system.
|
311 |
+
|
312 |
+
Explanation
|
313 |
+
===========
|
314 |
+
|
315 |
+
This function returns the potential energy of a system of Particle's and/or
|
316 |
+
RigidBody's. The potential energy of such a system is equal to the sum of
|
317 |
+
the potential energy of its constituents. Consider a system, S, comprising
|
318 |
+
a rigid body, A, and a particle, P. The potential energy of the system, V,
|
319 |
+
is equal to the vector sum of the potential energy of the particle, V1, and
|
320 |
+
the potential energy of the rigid body, V2, i.e.
|
321 |
+
|
322 |
+
V = V1 + V2
|
323 |
+
|
324 |
+
Potential energy is a scalar.
|
325 |
+
|
326 |
+
Parameters
|
327 |
+
==========
|
328 |
+
|
329 |
+
body1, body2, body3... : Particle and/or RigidBody
|
330 |
+
The body (or bodies) whose potential energy is required.
|
331 |
+
|
332 |
+
Examples
|
333 |
+
========
|
334 |
+
|
335 |
+
>>> from sympy.physics.mechanics import Point, Particle, ReferenceFrame
|
336 |
+
>>> from sympy.physics.mechanics import RigidBody, outer, potential_energy
|
337 |
+
>>> from sympy import symbols
|
338 |
+
>>> M, m, g, h = symbols('M m g h')
|
339 |
+
>>> N = ReferenceFrame('N')
|
340 |
+
>>> O = Point('O')
|
341 |
+
>>> O.set_vel(N, 0 * N.x)
|
342 |
+
>>> P = O.locatenew('P', 1 * N.x)
|
343 |
+
>>> Pa = Particle('Pa', P, m)
|
344 |
+
>>> Ac = O.locatenew('Ac', 2 * N.y)
|
345 |
+
>>> a = ReferenceFrame('a')
|
346 |
+
>>> I = outer(N.z, N.z)
|
347 |
+
>>> A = RigidBody('A', Ac, a, M, (I, Ac))
|
348 |
+
>>> Pa.potential_energy = m * g * h
|
349 |
+
>>> A.potential_energy = M * g * h
|
350 |
+
>>> potential_energy(Pa, A)
|
351 |
+
M*g*h + g*h*m
|
352 |
+
|
353 |
+
"""
|
354 |
+
|
355 |
+
pe_sys = S.Zero
|
356 |
+
for e in body:
|
357 |
+
if isinstance(e, (RigidBody, Particle)):
|
358 |
+
pe_sys += e.potential_energy
|
359 |
+
else:
|
360 |
+
raise TypeError('*body must have only Particle or RigidBody')
|
361 |
+
return pe_sys
|
362 |
+
|
363 |
+
|
364 |
+
def gravity(acceleration, *bodies):
|
365 |
+
"""
|
366 |
+
Returns a list of gravity forces given the acceleration
|
367 |
+
due to gravity and any number of particles or rigidbodies.
|
368 |
+
|
369 |
+
Example
|
370 |
+
=======
|
371 |
+
|
372 |
+
>>> from sympy.physics.mechanics import ReferenceFrame, Point, Particle, outer, RigidBody
|
373 |
+
>>> from sympy.physics.mechanics.functions import gravity
|
374 |
+
>>> from sympy import symbols
|
375 |
+
>>> N = ReferenceFrame('N')
|
376 |
+
>>> m, M, g = symbols('m M g')
|
377 |
+
>>> F1, F2 = symbols('F1 F2')
|
378 |
+
>>> po = Point('po')
|
379 |
+
>>> pa = Particle('pa', po, m)
|
380 |
+
>>> A = ReferenceFrame('A')
|
381 |
+
>>> P = Point('P')
|
382 |
+
>>> I = outer(A.x, A.x)
|
383 |
+
>>> B = RigidBody('B', P, A, M, (I, P))
|
384 |
+
>>> forceList = [(po, F1), (P, F2)]
|
385 |
+
>>> forceList.extend(gravity(g*N.y, pa, B))
|
386 |
+
>>> forceList
|
387 |
+
[(po, F1), (P, F2), (po, g*m*N.y), (P, M*g*N.y)]
|
388 |
+
|
389 |
+
"""
|
390 |
+
|
391 |
+
gravity_force = []
|
392 |
+
if not bodies:
|
393 |
+
raise TypeError("No bodies(instances of Particle or Rigidbody) were passed.")
|
394 |
+
|
395 |
+
for e in bodies:
|
396 |
+
point = getattr(e, 'masscenter', None)
|
397 |
+
if point is None:
|
398 |
+
point = e.point
|
399 |
+
|
400 |
+
gravity_force.append((point, e.mass*acceleration))
|
401 |
+
|
402 |
+
return gravity_force
|
403 |
+
|
404 |
+
|
405 |
+
def center_of_mass(point, *bodies):
|
406 |
+
"""
|
407 |
+
Returns the position vector from the given point to the center of mass
|
408 |
+
of the given bodies(particles or rigidbodies).
|
409 |
+
|
410 |
+
Example
|
411 |
+
=======
|
412 |
+
|
413 |
+
>>> from sympy import symbols, S
|
414 |
+
>>> from sympy.physics.vector import Point
|
415 |
+
>>> from sympy.physics.mechanics import Particle, ReferenceFrame, RigidBody, outer
|
416 |
+
>>> from sympy.physics.mechanics.functions import center_of_mass
|
417 |
+
>>> a = ReferenceFrame('a')
|
418 |
+
>>> m = symbols('m', real=True)
|
419 |
+
>>> p1 = Particle('p1', Point('p1_pt'), S(1))
|
420 |
+
>>> p2 = Particle('p2', Point('p2_pt'), S(2))
|
421 |
+
>>> p3 = Particle('p3', Point('p3_pt'), S(3))
|
422 |
+
>>> p4 = Particle('p4', Point('p4_pt'), m)
|
423 |
+
>>> b_f = ReferenceFrame('b_f')
|
424 |
+
>>> b_cm = Point('b_cm')
|
425 |
+
>>> mb = symbols('mb')
|
426 |
+
>>> b = RigidBody('b', b_cm, b_f, mb, (outer(b_f.x, b_f.x), b_cm))
|
427 |
+
>>> p2.point.set_pos(p1.point, a.x)
|
428 |
+
>>> p3.point.set_pos(p1.point, a.x + a.y)
|
429 |
+
>>> p4.point.set_pos(p1.point, a.y)
|
430 |
+
>>> b.masscenter.set_pos(p1.point, a.y + a.z)
|
431 |
+
>>> point_o=Point('o')
|
432 |
+
>>> point_o.set_pos(p1.point, center_of_mass(p1.point, p1, p2, p3, p4, b))
|
433 |
+
>>> expr = 5/(m + mb + 6)*a.x + (m + mb + 3)/(m + mb + 6)*a.y + mb/(m + mb + 6)*a.z
|
434 |
+
>>> point_o.pos_from(p1.point)
|
435 |
+
5/(m + mb + 6)*a.x + (m + mb + 3)/(m + mb + 6)*a.y + mb/(m + mb + 6)*a.z
|
436 |
+
|
437 |
+
"""
|
438 |
+
if not bodies:
|
439 |
+
raise TypeError("No bodies(instances of Particle or Rigidbody) were passed.")
|
440 |
+
|
441 |
+
total_mass = 0
|
442 |
+
vec = Vector(0)
|
443 |
+
for i in bodies:
|
444 |
+
total_mass += i.mass
|
445 |
+
|
446 |
+
masscenter = getattr(i, 'masscenter', None)
|
447 |
+
if masscenter is None:
|
448 |
+
masscenter = i.point
|
449 |
+
vec += i.mass*masscenter.pos_from(point)
|
450 |
+
|
451 |
+
return vec/total_mass
|
452 |
+
|
453 |
+
|
454 |
+
def Lagrangian(frame, *body):
|
455 |
+
"""Lagrangian of a multibody system.
|
456 |
+
|
457 |
+
Explanation
|
458 |
+
===========
|
459 |
+
|
460 |
+
This function returns the Lagrangian of a system of Particle's and/or
|
461 |
+
RigidBody's. The Lagrangian of such a system is equal to the difference
|
462 |
+
between the kinetic energies and potential energies of its constituents. If
|
463 |
+
T and V are the kinetic and potential energies of a system then it's
|
464 |
+
Lagrangian, L, is defined as
|
465 |
+
|
466 |
+
L = T - V
|
467 |
+
|
468 |
+
The Lagrangian is a scalar.
|
469 |
+
|
470 |
+
Parameters
|
471 |
+
==========
|
472 |
+
|
473 |
+
frame : ReferenceFrame
|
474 |
+
The frame in which the velocity or angular velocity of the body is
|
475 |
+
defined to determine the kinetic energy.
|
476 |
+
|
477 |
+
body1, body2, body3... : Particle and/or RigidBody
|
478 |
+
The body (or bodies) whose Lagrangian is required.
|
479 |
+
|
480 |
+
Examples
|
481 |
+
========
|
482 |
+
|
483 |
+
>>> from sympy.physics.mechanics import Point, Particle, ReferenceFrame
|
484 |
+
>>> from sympy.physics.mechanics import RigidBody, outer, Lagrangian
|
485 |
+
>>> from sympy import symbols
|
486 |
+
>>> M, m, g, h = symbols('M m g h')
|
487 |
+
>>> N = ReferenceFrame('N')
|
488 |
+
>>> O = Point('O')
|
489 |
+
>>> O.set_vel(N, 0 * N.x)
|
490 |
+
>>> P = O.locatenew('P', 1 * N.x)
|
491 |
+
>>> P.set_vel(N, 10 * N.x)
|
492 |
+
>>> Pa = Particle('Pa', P, 1)
|
493 |
+
>>> Ac = O.locatenew('Ac', 2 * N.y)
|
494 |
+
>>> Ac.set_vel(N, 5 * N.y)
|
495 |
+
>>> a = ReferenceFrame('a')
|
496 |
+
>>> a.set_ang_vel(N, 10 * N.z)
|
497 |
+
>>> I = outer(N.z, N.z)
|
498 |
+
>>> A = RigidBody('A', Ac, a, 20, (I, Ac))
|
499 |
+
>>> Pa.potential_energy = m * g * h
|
500 |
+
>>> A.potential_energy = M * g * h
|
501 |
+
>>> Lagrangian(N, Pa, A)
|
502 |
+
-M*g*h - g*h*m + 350
|
503 |
+
|
504 |
+
"""
|
505 |
+
|
506 |
+
if not isinstance(frame, ReferenceFrame):
|
507 |
+
raise TypeError('Please supply a valid ReferenceFrame')
|
508 |
+
for e in body:
|
509 |
+
if not isinstance(e, (RigidBody, Particle)):
|
510 |
+
raise TypeError('*body must have only Particle or RigidBody')
|
511 |
+
return kinetic_energy(frame, *body) - potential_energy(*body)
|
512 |
+
|
513 |
+
|
514 |
+
def find_dynamicsymbols(expression, exclude=None, reference_frame=None):
|
515 |
+
"""Find all dynamicsymbols in expression.
|
516 |
+
|
517 |
+
Explanation
|
518 |
+
===========
|
519 |
+
|
520 |
+
If the optional ``exclude`` kwarg is used, only dynamicsymbols
|
521 |
+
not in the iterable ``exclude`` are returned.
|
522 |
+
If we intend to apply this function on a vector, the optional
|
523 |
+
``reference_frame`` is also used to inform about the corresponding frame
|
524 |
+
with respect to which the dynamic symbols of the given vector is to be
|
525 |
+
determined.
|
526 |
+
|
527 |
+
Parameters
|
528 |
+
==========
|
529 |
+
|
530 |
+
expression : SymPy expression
|
531 |
+
|
532 |
+
exclude : iterable of dynamicsymbols, optional
|
533 |
+
|
534 |
+
reference_frame : ReferenceFrame, optional
|
535 |
+
The frame with respect to which the dynamic symbols of the
|
536 |
+
given vector is to be determined.
|
537 |
+
|
538 |
+
Examples
|
539 |
+
========
|
540 |
+
|
541 |
+
>>> from sympy.physics.mechanics import dynamicsymbols, find_dynamicsymbols
|
542 |
+
>>> from sympy.physics.mechanics import ReferenceFrame
|
543 |
+
>>> x, y = dynamicsymbols('x, y')
|
544 |
+
>>> expr = x + x.diff()*y
|
545 |
+
>>> find_dynamicsymbols(expr)
|
546 |
+
{x(t), y(t), Derivative(x(t), t)}
|
547 |
+
>>> find_dynamicsymbols(expr, exclude=[x, y])
|
548 |
+
{Derivative(x(t), t)}
|
549 |
+
>>> a, b, c = dynamicsymbols('a, b, c')
|
550 |
+
>>> A = ReferenceFrame('A')
|
551 |
+
>>> v = a * A.x + b * A.y + c * A.z
|
552 |
+
>>> find_dynamicsymbols(v, reference_frame=A)
|
553 |
+
{a(t), b(t), c(t)}
|
554 |
+
|
555 |
+
"""
|
556 |
+
t_set = {dynamicsymbols._t}
|
557 |
+
if exclude:
|
558 |
+
if iterable(exclude):
|
559 |
+
exclude_set = set(exclude)
|
560 |
+
else:
|
561 |
+
raise TypeError("exclude kwarg must be iterable")
|
562 |
+
else:
|
563 |
+
exclude_set = set()
|
564 |
+
if isinstance(expression, Vector):
|
565 |
+
if reference_frame is None:
|
566 |
+
raise ValueError("You must provide reference_frame when passing a "
|
567 |
+
"vector expression, got %s." % reference_frame)
|
568 |
+
else:
|
569 |
+
expression = expression.to_matrix(reference_frame)
|
570 |
+
return {i for i in expression.atoms(AppliedUndef, Derivative) if
|
571 |
+
i.free_symbols == t_set} - exclude_set
|
572 |
+
|
573 |
+
|
574 |
+
def msubs(expr, *sub_dicts, smart=False, **kwargs):
|
575 |
+
"""A custom subs for use on expressions derived in physics.mechanics.
|
576 |
+
|
577 |
+
Traverses the expression tree once, performing the subs found in sub_dicts.
|
578 |
+
Terms inside ``Derivative`` expressions are ignored:
|
579 |
+
|
580 |
+
Examples
|
581 |
+
========
|
582 |
+
|
583 |
+
>>> from sympy.physics.mechanics import dynamicsymbols, msubs
|
584 |
+
>>> x = dynamicsymbols('x')
|
585 |
+
>>> msubs(x.diff() + x, {x: 1})
|
586 |
+
Derivative(x(t), t) + 1
|
587 |
+
|
588 |
+
Note that sub_dicts can be a single dictionary, or several dictionaries:
|
589 |
+
|
590 |
+
>>> x, y, z = dynamicsymbols('x, y, z')
|
591 |
+
>>> sub1 = {x: 1, y: 2}
|
592 |
+
>>> sub2 = {z: 3, x.diff(): 4}
|
593 |
+
>>> msubs(x.diff() + x + y + z, sub1, sub2)
|
594 |
+
10
|
595 |
+
|
596 |
+
If smart=True (default False), also checks for conditions that may result
|
597 |
+
in ``nan``, but if simplified would yield a valid expression. For example:
|
598 |
+
|
599 |
+
>>> from sympy import sin, tan
|
600 |
+
>>> (sin(x)/tan(x)).subs(x, 0)
|
601 |
+
nan
|
602 |
+
>>> msubs(sin(x)/tan(x), {x: 0}, smart=True)
|
603 |
+
1
|
604 |
+
|
605 |
+
It does this by first replacing all ``tan`` with ``sin/cos``. Then each
|
606 |
+
node is traversed. If the node is a fraction, subs is first evaluated on
|
607 |
+
the denominator. If this results in 0, simplification of the entire
|
608 |
+
fraction is attempted. Using this selective simplification, only
|
609 |
+
subexpressions that result in 1/0 are targeted, resulting in faster
|
610 |
+
performance.
|
611 |
+
|
612 |
+
"""
|
613 |
+
|
614 |
+
sub_dict = dict_merge(*sub_dicts)
|
615 |
+
if smart:
|
616 |
+
func = _smart_subs
|
617 |
+
elif hasattr(expr, 'msubs'):
|
618 |
+
return expr.msubs(sub_dict)
|
619 |
+
else:
|
620 |
+
func = lambda expr, sub_dict: _crawl(expr, _sub_func, sub_dict)
|
621 |
+
if isinstance(expr, (Matrix, Vector, Dyadic)):
|
622 |
+
return expr.applyfunc(lambda x: func(x, sub_dict))
|
623 |
+
else:
|
624 |
+
return func(expr, sub_dict)
|
625 |
+
|
626 |
+
|
627 |
+
def _crawl(expr, func, *args, **kwargs):
|
628 |
+
"""Crawl the expression tree, and apply func to every node."""
|
629 |
+
val = func(expr, *args, **kwargs)
|
630 |
+
if val is not None:
|
631 |
+
return val
|
632 |
+
new_args = (_crawl(arg, func, *args, **kwargs) for arg in expr.args)
|
633 |
+
return expr.func(*new_args)
|
634 |
+
|
635 |
+
|
636 |
+
def _sub_func(expr, sub_dict):
|
637 |
+
"""Perform direct matching substitution, ignoring derivatives."""
|
638 |
+
if expr in sub_dict:
|
639 |
+
return sub_dict[expr]
|
640 |
+
elif not expr.args or expr.is_Derivative:
|
641 |
+
return expr
|
642 |
+
|
643 |
+
|
644 |
+
def _tan_repl_func(expr):
|
645 |
+
"""Replace tan with sin/cos."""
|
646 |
+
if isinstance(expr, tan):
|
647 |
+
return sin(*expr.args) / cos(*expr.args)
|
648 |
+
elif not expr.args or expr.is_Derivative:
|
649 |
+
return expr
|
650 |
+
|
651 |
+
|
652 |
+
def _smart_subs(expr, sub_dict):
|
653 |
+
"""Performs subs, checking for conditions that may result in `nan` or
|
654 |
+
`oo`, and attempts to simplify them out.
|
655 |
+
|
656 |
+
The expression tree is traversed twice, and the following steps are
|
657 |
+
performed on each expression node:
|
658 |
+
- First traverse:
|
659 |
+
Replace all `tan` with `sin/cos`.
|
660 |
+
- Second traverse:
|
661 |
+
If node is a fraction, check if the denominator evaluates to 0.
|
662 |
+
If so, attempt to simplify it out. Then if node is in sub_dict,
|
663 |
+
sub in the corresponding value.
|
664 |
+
|
665 |
+
"""
|
666 |
+
expr = _crawl(expr, _tan_repl_func)
|
667 |
+
|
668 |
+
def _recurser(expr, sub_dict):
|
669 |
+
# Decompose the expression into num, den
|
670 |
+
num, den = _fraction_decomp(expr)
|
671 |
+
if den != 1:
|
672 |
+
# If there is a non trivial denominator, we need to handle it
|
673 |
+
denom_subbed = _recurser(den, sub_dict)
|
674 |
+
if denom_subbed.evalf() == 0:
|
675 |
+
# If denom is 0 after this, attempt to simplify the bad expr
|
676 |
+
expr = simplify(expr)
|
677 |
+
else:
|
678 |
+
# Expression won't result in nan, find numerator
|
679 |
+
num_subbed = _recurser(num, sub_dict)
|
680 |
+
return num_subbed / denom_subbed
|
681 |
+
# We have to crawl the tree manually, because `expr` may have been
|
682 |
+
# modified in the simplify step. First, perform subs as normal:
|
683 |
+
val = _sub_func(expr, sub_dict)
|
684 |
+
if val is not None:
|
685 |
+
return val
|
686 |
+
new_args = (_recurser(arg, sub_dict) for arg in expr.args)
|
687 |
+
return expr.func(*new_args)
|
688 |
+
return _recurser(expr, sub_dict)
|
689 |
+
|
690 |
+
|
691 |
+
def _fraction_decomp(expr):
|
692 |
+
"""Return num, den such that expr = num/den."""
|
693 |
+
if not isinstance(expr, Mul):
|
694 |
+
return expr, 1
|
695 |
+
num = []
|
696 |
+
den = []
|
697 |
+
for a in expr.args:
|
698 |
+
if a.is_Pow and a.args[1] < 0:
|
699 |
+
den.append(1 / a)
|
700 |
+
else:
|
701 |
+
num.append(a)
|
702 |
+
if not den:
|
703 |
+
return expr, 1
|
704 |
+
num = Mul(*num)
|
705 |
+
den = Mul(*den)
|
706 |
+
return num, den
|
707 |
+
|
708 |
+
|
709 |
+
def _f_list_parser(fl, ref_frame):
|
710 |
+
"""Parses the provided forcelist composed of items
|
711 |
+
of the form (obj, force).
|
712 |
+
Returns a tuple containing:
|
713 |
+
vel_list: The velocity (ang_vel for Frames, vel for Points) in
|
714 |
+
the provided reference frame.
|
715 |
+
f_list: The forces.
|
716 |
+
|
717 |
+
Used internally in the KanesMethod and LagrangesMethod classes.
|
718 |
+
|
719 |
+
"""
|
720 |
+
def flist_iter():
|
721 |
+
for pair in fl:
|
722 |
+
obj, force = pair
|
723 |
+
if isinstance(obj, ReferenceFrame):
|
724 |
+
yield obj.ang_vel_in(ref_frame), force
|
725 |
+
elif isinstance(obj, Point):
|
726 |
+
yield obj.vel(ref_frame), force
|
727 |
+
else:
|
728 |
+
raise TypeError('First entry in each forcelist pair must '
|
729 |
+
'be a point or frame.')
|
730 |
+
|
731 |
+
if not fl:
|
732 |
+
vel_list, f_list = (), ()
|
733 |
+
else:
|
734 |
+
unzip = lambda l: list(zip(*l)) if l[0] else [(), ()]
|
735 |
+
vel_list, f_list = unzip(list(flist_iter()))
|
736 |
+
return vel_list, f_list
|
737 |
+
|
738 |
+
|
739 |
+
def _validate_coordinates(coordinates=None, speeds=None, check_duplicates=True,
|
740 |
+
is_dynamicsymbols=True):
|
741 |
+
t_set = {dynamicsymbols._t}
|
742 |
+
# Convert input to iterables
|
743 |
+
if coordinates is None:
|
744 |
+
coordinates = []
|
745 |
+
elif not iterable(coordinates):
|
746 |
+
coordinates = [coordinates]
|
747 |
+
if speeds is None:
|
748 |
+
speeds = []
|
749 |
+
elif not iterable(speeds):
|
750 |
+
speeds = [speeds]
|
751 |
+
|
752 |
+
if check_duplicates: # Check for duplicates
|
753 |
+
seen = set()
|
754 |
+
coord_duplicates = {x for x in coordinates if x in seen or seen.add(x)}
|
755 |
+
seen = set()
|
756 |
+
speed_duplicates = {x for x in speeds if x in seen or seen.add(x)}
|
757 |
+
overlap = set(coordinates).intersection(speeds)
|
758 |
+
if coord_duplicates:
|
759 |
+
raise ValueError(f'The generalized coordinates {coord_duplicates} '
|
760 |
+
f'are duplicated, all generalized coordinates '
|
761 |
+
f'should be unique.')
|
762 |
+
if speed_duplicates:
|
763 |
+
raise ValueError(f'The generalized speeds {speed_duplicates} are '
|
764 |
+
f'duplicated, all generalized speeds should be '
|
765 |
+
f'unique.')
|
766 |
+
if overlap:
|
767 |
+
raise ValueError(f'{overlap} are defined as both generalized '
|
768 |
+
f'coordinates and generalized speeds.')
|
769 |
+
if is_dynamicsymbols: # Check whether all coordinates are dynamicsymbols
|
770 |
+
for coordinate in coordinates:
|
771 |
+
if not (isinstance(coordinate, (AppliedUndef, Derivative)) and
|
772 |
+
coordinate.free_symbols == t_set):
|
773 |
+
raise ValueError(f'Generalized coordinate "{coordinate}" is not'
|
774 |
+
f' a dynamicsymbol.')
|
775 |
+
for speed in speeds:
|
776 |
+
if not (isinstance(speed, (AppliedUndef, Derivative)) and
|
777 |
+
speed.free_symbols == t_set):
|
778 |
+
raise ValueError(f'Generalized speed "{speed}" is not a '
|
779 |
+
f'dynamicsymbol.')
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/joint.py
ADDED
@@ -0,0 +1,2163 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
# coding=utf-8
|
2 |
+
|
3 |
+
from abc import ABC, abstractmethod
|
4 |
+
|
5 |
+
from sympy.core.backend import pi, AppliedUndef, Derivative, Matrix
|
6 |
+
from sympy.physics.mechanics.body import Body
|
7 |
+
from sympy.physics.mechanics.functions import _validate_coordinates
|
8 |
+
from sympy.physics.vector import (Vector, dynamicsymbols, cross, Point,
|
9 |
+
ReferenceFrame)
|
10 |
+
from sympy.utilities.iterables import iterable
|
11 |
+
from sympy.utilities.exceptions import sympy_deprecation_warning
|
12 |
+
|
13 |
+
__all__ = ['Joint', 'PinJoint', 'PrismaticJoint', 'CylindricalJoint',
|
14 |
+
'PlanarJoint', 'SphericalJoint', 'WeldJoint']
|
15 |
+
|
16 |
+
|
17 |
+
class Joint(ABC):
|
18 |
+
"""Abstract base class for all specific joints.
|
19 |
+
|
20 |
+
Explanation
|
21 |
+
===========
|
22 |
+
|
23 |
+
A joint subtracts degrees of freedom from a body. This is the base class
|
24 |
+
for all specific joints and holds all common methods acting as an interface
|
25 |
+
for all joints. Custom joint can be created by inheriting Joint class and
|
26 |
+
defining all abstract functions.
|
27 |
+
|
28 |
+
The abstract methods are:
|
29 |
+
|
30 |
+
- ``_generate_coordinates``
|
31 |
+
- ``_generate_speeds``
|
32 |
+
- ``_orient_frames``
|
33 |
+
- ``_set_angular_velocity``
|
34 |
+
- ``_set_linear_velocity``
|
35 |
+
|
36 |
+
Parameters
|
37 |
+
==========
|
38 |
+
|
39 |
+
name : string
|
40 |
+
A unique name for the joint.
|
41 |
+
parent : Body
|
42 |
+
The parent body of joint.
|
43 |
+
child : Body
|
44 |
+
The child body of joint.
|
45 |
+
coordinates : iterable of dynamicsymbols, optional
|
46 |
+
Generalized coordinates of the joint.
|
47 |
+
speeds : iterable of dynamicsymbols, optional
|
48 |
+
Generalized speeds of joint.
|
49 |
+
parent_point : Point or Vector, optional
|
50 |
+
Attachment point where the joint is fixed to the parent body. If a
|
51 |
+
vector is provided, then the attachment point is computed by adding the
|
52 |
+
vector to the body's mass center. The default value is the parent's mass
|
53 |
+
center.
|
54 |
+
child_point : Point or Vector, optional
|
55 |
+
Attachment point where the joint is fixed to the child body. If a
|
56 |
+
vector is provided, then the attachment point is computed by adding the
|
57 |
+
vector to the body's mass center. The default value is the child's mass
|
58 |
+
center.
|
59 |
+
parent_axis : Vector, optional
|
60 |
+
.. deprecated:: 1.12
|
61 |
+
Axis fixed in the parent body which aligns with an axis fixed in the
|
62 |
+
child body. The default is the x axis of parent's reference frame.
|
63 |
+
For more information on this deprecation, see
|
64 |
+
:ref:`deprecated-mechanics-joint-axis`.
|
65 |
+
child_axis : Vector, optional
|
66 |
+
.. deprecated:: 1.12
|
67 |
+
Axis fixed in the child body which aligns with an axis fixed in the
|
68 |
+
parent body. The default is the x axis of child's reference frame.
|
69 |
+
For more information on this deprecation, see
|
70 |
+
:ref:`deprecated-mechanics-joint-axis`.
|
71 |
+
parent_interframe : ReferenceFrame, optional
|
72 |
+
Intermediate frame of the parent body with respect to which the joint
|
73 |
+
transformation is formulated. If a Vector is provided then an interframe
|
74 |
+
is created which aligns its X axis with the given vector. The default
|
75 |
+
value is the parent's own frame.
|
76 |
+
child_interframe : ReferenceFrame, optional
|
77 |
+
Intermediate frame of the child body with respect to which the joint
|
78 |
+
transformation is formulated. If a Vector is provided then an interframe
|
79 |
+
is created which aligns its X axis with the given vector. The default
|
80 |
+
value is the child's own frame.
|
81 |
+
parent_joint_pos : Point or Vector, optional
|
82 |
+
.. deprecated:: 1.12
|
83 |
+
This argument is replaced by parent_point and will be removed in a
|
84 |
+
future version.
|
85 |
+
See :ref:`deprecated-mechanics-joint-pos` for more information.
|
86 |
+
child_joint_pos : Point or Vector, optional
|
87 |
+
.. deprecated:: 1.12
|
88 |
+
This argument is replaced by child_point and will be removed in a
|
89 |
+
future version.
|
90 |
+
See :ref:`deprecated-mechanics-joint-pos` for more information.
|
91 |
+
|
92 |
+
Attributes
|
93 |
+
==========
|
94 |
+
|
95 |
+
name : string
|
96 |
+
The joint's name.
|
97 |
+
parent : Body
|
98 |
+
The joint's parent body.
|
99 |
+
child : Body
|
100 |
+
The joint's child body.
|
101 |
+
coordinates : Matrix
|
102 |
+
Matrix of the joint's generalized coordinates.
|
103 |
+
speeds : Matrix
|
104 |
+
Matrix of the joint's generalized speeds.
|
105 |
+
parent_point : Point
|
106 |
+
Attachment point where the joint is fixed to the parent body.
|
107 |
+
child_point : Point
|
108 |
+
Attachment point where the joint is fixed to the child body.
|
109 |
+
parent_axis : Vector
|
110 |
+
The axis fixed in the parent frame that represents the joint.
|
111 |
+
child_axis : Vector
|
112 |
+
The axis fixed in the child frame that represents the joint.
|
113 |
+
parent_interframe : ReferenceFrame
|
114 |
+
Intermediate frame of the parent body with respect to which the joint
|
115 |
+
transformation is formulated.
|
116 |
+
child_interframe : ReferenceFrame
|
117 |
+
Intermediate frame of the child body with respect to which the joint
|
118 |
+
transformation is formulated.
|
119 |
+
kdes : Matrix
|
120 |
+
Kinematical differential equations of the joint.
|
121 |
+
|
122 |
+
Notes
|
123 |
+
=====
|
124 |
+
|
125 |
+
When providing a vector as the intermediate frame, a new intermediate frame
|
126 |
+
is created which aligns its X axis with the provided vector. This is done
|
127 |
+
with a single fixed rotation about a rotation axis. This rotation axis is
|
128 |
+
determined by taking the cross product of the ``body.x`` axis with the
|
129 |
+
provided vector. In the case where the provided vector is in the ``-body.x``
|
130 |
+
direction, the rotation is done about the ``body.y`` axis.
|
131 |
+
|
132 |
+
"""
|
133 |
+
|
134 |
+
def __init__(self, name, parent, child, coordinates=None, speeds=None,
|
135 |
+
parent_point=None, child_point=None, parent_axis=None,
|
136 |
+
child_axis=None, parent_interframe=None, child_interframe=None,
|
137 |
+
parent_joint_pos=None, child_joint_pos=None):
|
138 |
+
|
139 |
+
if not isinstance(name, str):
|
140 |
+
raise TypeError('Supply a valid name.')
|
141 |
+
self._name = name
|
142 |
+
|
143 |
+
if not isinstance(parent, Body):
|
144 |
+
raise TypeError('Parent must be an instance of Body.')
|
145 |
+
self._parent = parent
|
146 |
+
|
147 |
+
if not isinstance(child, Body):
|
148 |
+
raise TypeError('Parent must be an instance of Body.')
|
149 |
+
self._child = child
|
150 |
+
|
151 |
+
self._coordinates = self._generate_coordinates(coordinates)
|
152 |
+
self._speeds = self._generate_speeds(speeds)
|
153 |
+
_validate_coordinates(self.coordinates, self.speeds)
|
154 |
+
self._kdes = self._generate_kdes()
|
155 |
+
|
156 |
+
self._parent_axis = self._axis(parent_axis, parent.frame)
|
157 |
+
self._child_axis = self._axis(child_axis, child.frame)
|
158 |
+
|
159 |
+
if parent_joint_pos is not None or child_joint_pos is not None:
|
160 |
+
sympy_deprecation_warning(
|
161 |
+
"""
|
162 |
+
The parent_joint_pos and child_joint_pos arguments for the Joint
|
163 |
+
classes are deprecated. Instead use parent_point and child_point.
|
164 |
+
""",
|
165 |
+
deprecated_since_version="1.12",
|
166 |
+
active_deprecations_target="deprecated-mechanics-joint-pos",
|
167 |
+
stacklevel=4
|
168 |
+
)
|
169 |
+
if parent_point is None:
|
170 |
+
parent_point = parent_joint_pos
|
171 |
+
if child_point is None:
|
172 |
+
child_point = child_joint_pos
|
173 |
+
self._parent_point = self._locate_joint_pos(parent, parent_point)
|
174 |
+
self._child_point = self._locate_joint_pos(child, child_point)
|
175 |
+
if parent_axis is not None or child_axis is not None:
|
176 |
+
sympy_deprecation_warning(
|
177 |
+
"""
|
178 |
+
The parent_axis and child_axis arguments for the Joint classes
|
179 |
+
are deprecated. Instead use parent_interframe, child_interframe.
|
180 |
+
""",
|
181 |
+
deprecated_since_version="1.12",
|
182 |
+
active_deprecations_target="deprecated-mechanics-joint-axis",
|
183 |
+
stacklevel=4
|
184 |
+
)
|
185 |
+
if parent_interframe is None:
|
186 |
+
parent_interframe = parent_axis
|
187 |
+
if child_interframe is None:
|
188 |
+
child_interframe = child_axis
|
189 |
+
self._parent_interframe = self._locate_joint_frame(parent,
|
190 |
+
parent_interframe)
|
191 |
+
self._child_interframe = self._locate_joint_frame(child,
|
192 |
+
child_interframe)
|
193 |
+
|
194 |
+
self._orient_frames()
|
195 |
+
self._set_angular_velocity()
|
196 |
+
self._set_linear_velocity()
|
197 |
+
|
198 |
+
def __str__(self):
|
199 |
+
return self.name
|
200 |
+
|
201 |
+
def __repr__(self):
|
202 |
+
return self.__str__()
|
203 |
+
|
204 |
+
@property
|
205 |
+
def name(self):
|
206 |
+
"""Name of the joint."""
|
207 |
+
return self._name
|
208 |
+
|
209 |
+
@property
|
210 |
+
def parent(self):
|
211 |
+
"""Parent body of Joint."""
|
212 |
+
return self._parent
|
213 |
+
|
214 |
+
@property
|
215 |
+
def child(self):
|
216 |
+
"""Child body of Joint."""
|
217 |
+
return self._child
|
218 |
+
|
219 |
+
@property
|
220 |
+
def coordinates(self):
|
221 |
+
"""Matrix of the joint's generalized coordinates."""
|
222 |
+
return self._coordinates
|
223 |
+
|
224 |
+
@property
|
225 |
+
def speeds(self):
|
226 |
+
"""Matrix of the joint's generalized speeds."""
|
227 |
+
return self._speeds
|
228 |
+
|
229 |
+
@property
|
230 |
+
def kdes(self):
|
231 |
+
"""Kinematical differential equations of the joint."""
|
232 |
+
return self._kdes
|
233 |
+
|
234 |
+
@property
|
235 |
+
def parent_axis(self):
|
236 |
+
"""The axis of parent frame."""
|
237 |
+
# Will be removed with `deprecated-mechanics-joint-axis`
|
238 |
+
return self._parent_axis
|
239 |
+
|
240 |
+
@property
|
241 |
+
def child_axis(self):
|
242 |
+
"""The axis of child frame."""
|
243 |
+
# Will be removed with `deprecated-mechanics-joint-axis`
|
244 |
+
return self._child_axis
|
245 |
+
|
246 |
+
@property
|
247 |
+
def parent_point(self):
|
248 |
+
"""Attachment point where the joint is fixed to the parent body."""
|
249 |
+
return self._parent_point
|
250 |
+
|
251 |
+
@property
|
252 |
+
def child_point(self):
|
253 |
+
"""Attachment point where the joint is fixed to the child body."""
|
254 |
+
return self._child_point
|
255 |
+
|
256 |
+
@property
|
257 |
+
def parent_interframe(self):
|
258 |
+
return self._parent_interframe
|
259 |
+
|
260 |
+
@property
|
261 |
+
def child_interframe(self):
|
262 |
+
return self._child_interframe
|
263 |
+
|
264 |
+
@abstractmethod
|
265 |
+
def _generate_coordinates(self, coordinates):
|
266 |
+
"""Generate Matrix of the joint's generalized coordinates."""
|
267 |
+
pass
|
268 |
+
|
269 |
+
@abstractmethod
|
270 |
+
def _generate_speeds(self, speeds):
|
271 |
+
"""Generate Matrix of the joint's generalized speeds."""
|
272 |
+
pass
|
273 |
+
|
274 |
+
@abstractmethod
|
275 |
+
def _orient_frames(self):
|
276 |
+
"""Orient frames as per the joint."""
|
277 |
+
pass
|
278 |
+
|
279 |
+
@abstractmethod
|
280 |
+
def _set_angular_velocity(self):
|
281 |
+
"""Set angular velocity of the joint related frames."""
|
282 |
+
pass
|
283 |
+
|
284 |
+
@abstractmethod
|
285 |
+
def _set_linear_velocity(self):
|
286 |
+
"""Set velocity of related points to the joint."""
|
287 |
+
pass
|
288 |
+
|
289 |
+
@staticmethod
|
290 |
+
def _to_vector(matrix, frame):
|
291 |
+
"""Converts a matrix to a vector in the given frame."""
|
292 |
+
return Vector([(matrix, frame)])
|
293 |
+
|
294 |
+
@staticmethod
|
295 |
+
def _axis(ax, *frames):
|
296 |
+
"""Check whether an axis is fixed in one of the frames."""
|
297 |
+
if ax is None:
|
298 |
+
ax = frames[0].x
|
299 |
+
return ax
|
300 |
+
if not isinstance(ax, Vector):
|
301 |
+
raise TypeError("Axis must be a Vector.")
|
302 |
+
ref_frame = None # Find a body in which the axis can be expressed
|
303 |
+
for frame in frames:
|
304 |
+
try:
|
305 |
+
ax.to_matrix(frame)
|
306 |
+
except ValueError:
|
307 |
+
pass
|
308 |
+
else:
|
309 |
+
ref_frame = frame
|
310 |
+
break
|
311 |
+
if ref_frame is None:
|
312 |
+
raise ValueError("Axis cannot be expressed in one of the body's "
|
313 |
+
"frames.")
|
314 |
+
if not ax.dt(ref_frame) == 0:
|
315 |
+
raise ValueError('Axis cannot be time-varying when viewed from the '
|
316 |
+
'associated body.')
|
317 |
+
return ax
|
318 |
+
|
319 |
+
@staticmethod
|
320 |
+
def _choose_rotation_axis(frame, axis):
|
321 |
+
components = axis.to_matrix(frame)
|
322 |
+
x, y, z = components[0], components[1], components[2]
|
323 |
+
|
324 |
+
if x != 0:
|
325 |
+
if y != 0:
|
326 |
+
if z != 0:
|
327 |
+
return cross(axis, frame.x)
|
328 |
+
if z != 0:
|
329 |
+
return frame.y
|
330 |
+
return frame.z
|
331 |
+
else:
|
332 |
+
if y != 0:
|
333 |
+
return frame.x
|
334 |
+
return frame.y
|
335 |
+
|
336 |
+
@staticmethod
|
337 |
+
def _create_aligned_interframe(frame, align_axis, frame_axis=None,
|
338 |
+
frame_name=None):
|
339 |
+
"""
|
340 |
+
Returns an intermediate frame, where the ``frame_axis`` defined in
|
341 |
+
``frame`` is aligned with ``axis``. By default this means that the X
|
342 |
+
axis will be aligned with ``axis``.
|
343 |
+
|
344 |
+
Parameters
|
345 |
+
==========
|
346 |
+
|
347 |
+
frame : Body or ReferenceFrame
|
348 |
+
The body or reference frame with respect to which the intermediate
|
349 |
+
frame is oriented.
|
350 |
+
align_axis : Vector
|
351 |
+
The vector with respect to which the intermediate frame will be
|
352 |
+
aligned.
|
353 |
+
frame_axis : Vector
|
354 |
+
The vector of the frame which should get aligned with ``axis``. The
|
355 |
+
default is the X axis of the frame.
|
356 |
+
frame_name : string
|
357 |
+
Name of the to be created intermediate frame. The default adds
|
358 |
+
"_int_frame" to the name of ``frame``.
|
359 |
+
|
360 |
+
Example
|
361 |
+
=======
|
362 |
+
|
363 |
+
An intermediate frame, where the X axis of the parent becomes aligned
|
364 |
+
with ``parent.y + parent.z`` can be created as follows:
|
365 |
+
|
366 |
+
>>> from sympy.physics.mechanics.joint import Joint
|
367 |
+
>>> from sympy.physics.mechanics import Body
|
368 |
+
>>> parent = Body('parent')
|
369 |
+
>>> parent_interframe = Joint._create_aligned_interframe(
|
370 |
+
... parent, parent.y + parent.z)
|
371 |
+
>>> parent_interframe
|
372 |
+
parent_int_frame
|
373 |
+
>>> parent.dcm(parent_interframe)
|
374 |
+
Matrix([
|
375 |
+
[ 0, -sqrt(2)/2, -sqrt(2)/2],
|
376 |
+
[sqrt(2)/2, 1/2, -1/2],
|
377 |
+
[sqrt(2)/2, -1/2, 1/2]])
|
378 |
+
>>> (parent.y + parent.z).express(parent_interframe)
|
379 |
+
sqrt(2)*parent_int_frame.x
|
380 |
+
|
381 |
+
Notes
|
382 |
+
=====
|
383 |
+
|
384 |
+
The direction cosine matrix between the given frame and intermediate
|
385 |
+
frame is formed using a simple rotation about an axis that is normal to
|
386 |
+
both ``align_axis`` and ``frame_axis``. In general, the normal axis is
|
387 |
+
formed by crossing the ``frame_axis`` with the ``align_axis``. The
|
388 |
+
exception is if the axes are parallel with opposite directions, in which
|
389 |
+
case the rotation vector is chosen using the rules in the following
|
390 |
+
table with the vectors expressed in the given frame:
|
391 |
+
|
392 |
+
.. list-table::
|
393 |
+
:header-rows: 1
|
394 |
+
|
395 |
+
* - ``align_axis``
|
396 |
+
- ``frame_axis``
|
397 |
+
- ``rotation_axis``
|
398 |
+
* - ``-x``
|
399 |
+
- ``x``
|
400 |
+
- ``z``
|
401 |
+
* - ``-y``
|
402 |
+
- ``y``
|
403 |
+
- ``x``
|
404 |
+
* - ``-z``
|
405 |
+
- ``z``
|
406 |
+
- ``y``
|
407 |
+
* - ``-x-y``
|
408 |
+
- ``x+y``
|
409 |
+
- ``z``
|
410 |
+
* - ``-y-z``
|
411 |
+
- ``y+z``
|
412 |
+
- ``x``
|
413 |
+
* - ``-x-z``
|
414 |
+
- ``x+z``
|
415 |
+
- ``y``
|
416 |
+
* - ``-x-y-z``
|
417 |
+
- ``x+y+z``
|
418 |
+
- ``(x+y+z) × x``
|
419 |
+
|
420 |
+
"""
|
421 |
+
if isinstance(frame, Body):
|
422 |
+
frame = frame.frame
|
423 |
+
if frame_axis is None:
|
424 |
+
frame_axis = frame.x
|
425 |
+
if frame_name is None:
|
426 |
+
if frame.name[-6:] == '_frame':
|
427 |
+
frame_name = f'{frame.name[:-6]}_int_frame'
|
428 |
+
else:
|
429 |
+
frame_name = f'{frame.name}_int_frame'
|
430 |
+
angle = frame_axis.angle_between(align_axis)
|
431 |
+
rotation_axis = cross(frame_axis, align_axis)
|
432 |
+
if rotation_axis == Vector(0) and angle == 0:
|
433 |
+
return frame
|
434 |
+
if angle == pi:
|
435 |
+
rotation_axis = Joint._choose_rotation_axis(frame, align_axis)
|
436 |
+
|
437 |
+
int_frame = ReferenceFrame(frame_name)
|
438 |
+
int_frame.orient_axis(frame, rotation_axis, angle)
|
439 |
+
int_frame.set_ang_vel(frame, 0 * rotation_axis)
|
440 |
+
return int_frame
|
441 |
+
|
442 |
+
def _generate_kdes(self):
|
443 |
+
"""Generate kinematical differential equations."""
|
444 |
+
kdes = []
|
445 |
+
t = dynamicsymbols._t
|
446 |
+
for i in range(len(self.coordinates)):
|
447 |
+
kdes.append(-self.coordinates[i].diff(t) + self.speeds[i])
|
448 |
+
return Matrix(kdes)
|
449 |
+
|
450 |
+
def _locate_joint_pos(self, body, joint_pos):
|
451 |
+
"""Returns the attachment point of a body."""
|
452 |
+
if joint_pos is None:
|
453 |
+
return body.masscenter
|
454 |
+
if not isinstance(joint_pos, (Point, Vector)):
|
455 |
+
raise TypeError('Attachment point must be a Point or Vector.')
|
456 |
+
if isinstance(joint_pos, Vector):
|
457 |
+
point_name = f'{self.name}_{body.name}_joint'
|
458 |
+
joint_pos = body.masscenter.locatenew(point_name, joint_pos)
|
459 |
+
if not joint_pos.pos_from(body.masscenter).dt(body.frame) == 0:
|
460 |
+
raise ValueError('Attachment point must be fixed to the associated '
|
461 |
+
'body.')
|
462 |
+
return joint_pos
|
463 |
+
|
464 |
+
def _locate_joint_frame(self, body, interframe):
|
465 |
+
"""Returns the attachment frame of a body."""
|
466 |
+
if interframe is None:
|
467 |
+
return body.frame
|
468 |
+
if isinstance(interframe, Vector):
|
469 |
+
interframe = Joint._create_aligned_interframe(
|
470 |
+
body, interframe,
|
471 |
+
frame_name=f'{self.name}_{body.name}_int_frame')
|
472 |
+
elif not isinstance(interframe, ReferenceFrame):
|
473 |
+
raise TypeError('Interframe must be a ReferenceFrame.')
|
474 |
+
if not interframe.ang_vel_in(body.frame) == 0:
|
475 |
+
raise ValueError(f'Interframe {interframe} is not fixed to body '
|
476 |
+
f'{body}.')
|
477 |
+
body.masscenter.set_vel(interframe, 0) # Fixate interframe to body
|
478 |
+
return interframe
|
479 |
+
|
480 |
+
def _fill_coordinate_list(self, coordinates, n_coords, label='q', offset=0,
|
481 |
+
number_single=False):
|
482 |
+
"""Helper method for _generate_coordinates and _generate_speeds.
|
483 |
+
|
484 |
+
Parameters
|
485 |
+
==========
|
486 |
+
|
487 |
+
coordinates : iterable
|
488 |
+
Iterable of coordinates or speeds that have been provided.
|
489 |
+
n_coords : Integer
|
490 |
+
Number of coordinates that should be returned.
|
491 |
+
label : String, optional
|
492 |
+
Coordinate type either 'q' (coordinates) or 'u' (speeds). The
|
493 |
+
Default is 'q'.
|
494 |
+
offset : Integer
|
495 |
+
Count offset when creating new dynamicsymbols. The default is 0.
|
496 |
+
number_single : Boolean
|
497 |
+
Boolean whether if n_coords == 1, number should still be used. The
|
498 |
+
default is False.
|
499 |
+
|
500 |
+
"""
|
501 |
+
|
502 |
+
def create_symbol(number):
|
503 |
+
if n_coords == 1 and not number_single:
|
504 |
+
return dynamicsymbols(f'{label}_{self.name}')
|
505 |
+
return dynamicsymbols(f'{label}{number}_{self.name}')
|
506 |
+
|
507 |
+
name = 'generalized coordinate' if label == 'q' else 'generalized speed'
|
508 |
+
generated_coordinates = []
|
509 |
+
if coordinates is None:
|
510 |
+
coordinates = []
|
511 |
+
elif not iterable(coordinates):
|
512 |
+
coordinates = [coordinates]
|
513 |
+
if not (len(coordinates) == 0 or len(coordinates) == n_coords):
|
514 |
+
raise ValueError(f'Expected {n_coords} {name}s, instead got '
|
515 |
+
f'{len(coordinates)} {name}s.')
|
516 |
+
# Supports more iterables, also Matrix
|
517 |
+
for i, coord in enumerate(coordinates):
|
518 |
+
if coord is None:
|
519 |
+
generated_coordinates.append(create_symbol(i + offset))
|
520 |
+
elif isinstance(coord, (AppliedUndef, Derivative)):
|
521 |
+
generated_coordinates.append(coord)
|
522 |
+
else:
|
523 |
+
raise TypeError(f'The {name} {coord} should have been a '
|
524 |
+
f'dynamicsymbol.')
|
525 |
+
for i in range(len(coordinates) + offset, n_coords + offset):
|
526 |
+
generated_coordinates.append(create_symbol(i))
|
527 |
+
return Matrix(generated_coordinates)
|
528 |
+
|
529 |
+
|
530 |
+
class PinJoint(Joint):
|
531 |
+
"""Pin (Revolute) Joint.
|
532 |
+
|
533 |
+
.. image:: PinJoint.svg
|
534 |
+
|
535 |
+
Explanation
|
536 |
+
===========
|
537 |
+
|
538 |
+
A pin joint is defined such that the joint rotation axis is fixed in both
|
539 |
+
the child and parent and the location of the joint is relative to the mass
|
540 |
+
center of each body. The child rotates an angle, θ, from the parent about
|
541 |
+
the rotation axis and has a simple angular speed, ω, relative to the
|
542 |
+
parent. The direction cosine matrix between the child interframe and
|
543 |
+
parent interframe is formed using a simple rotation about the joint axis.
|
544 |
+
The page on the joints framework gives a more detailed explanation of the
|
545 |
+
intermediate frames.
|
546 |
+
|
547 |
+
Parameters
|
548 |
+
==========
|
549 |
+
|
550 |
+
name : string
|
551 |
+
A unique name for the joint.
|
552 |
+
parent : Body
|
553 |
+
The parent body of joint.
|
554 |
+
child : Body
|
555 |
+
The child body of joint.
|
556 |
+
coordinates : dynamicsymbol, optional
|
557 |
+
Generalized coordinates of the joint.
|
558 |
+
speeds : dynamicsymbol, optional
|
559 |
+
Generalized speeds of joint.
|
560 |
+
parent_point : Point or Vector, optional
|
561 |
+
Attachment point where the joint is fixed to the parent body. If a
|
562 |
+
vector is provided, then the attachment point is computed by adding the
|
563 |
+
vector to the body's mass center. The default value is the parent's mass
|
564 |
+
center.
|
565 |
+
child_point : Point or Vector, optional
|
566 |
+
Attachment point where the joint is fixed to the child body. If a
|
567 |
+
vector is provided, then the attachment point is computed by adding the
|
568 |
+
vector to the body's mass center. The default value is the child's mass
|
569 |
+
center.
|
570 |
+
parent_axis : Vector, optional
|
571 |
+
.. deprecated:: 1.12
|
572 |
+
Axis fixed in the parent body which aligns with an axis fixed in the
|
573 |
+
child body. The default is the x axis of parent's reference frame.
|
574 |
+
For more information on this deprecation, see
|
575 |
+
:ref:`deprecated-mechanics-joint-axis`.
|
576 |
+
child_axis : Vector, optional
|
577 |
+
.. deprecated:: 1.12
|
578 |
+
Axis fixed in the child body which aligns with an axis fixed in the
|
579 |
+
parent body. The default is the x axis of child's reference frame.
|
580 |
+
For more information on this deprecation, see
|
581 |
+
:ref:`deprecated-mechanics-joint-axis`.
|
582 |
+
parent_interframe : ReferenceFrame, optional
|
583 |
+
Intermediate frame of the parent body with respect to which the joint
|
584 |
+
transformation is formulated. If a Vector is provided then an interframe
|
585 |
+
is created which aligns its X axis with the given vector. The default
|
586 |
+
value is the parent's own frame.
|
587 |
+
child_interframe : ReferenceFrame, optional
|
588 |
+
Intermediate frame of the child body with respect to which the joint
|
589 |
+
transformation is formulated. If a Vector is provided then an interframe
|
590 |
+
is created which aligns its X axis with the given vector. The default
|
591 |
+
value is the child's own frame.
|
592 |
+
joint_axis : Vector
|
593 |
+
The axis about which the rotation occurs. Note that the components
|
594 |
+
of this axis are the same in the parent_interframe and child_interframe.
|
595 |
+
parent_joint_pos : Point or Vector, optional
|
596 |
+
.. deprecated:: 1.12
|
597 |
+
This argument is replaced by parent_point and will be removed in a
|
598 |
+
future version.
|
599 |
+
See :ref:`deprecated-mechanics-joint-pos` for more information.
|
600 |
+
child_joint_pos : Point or Vector, optional
|
601 |
+
.. deprecated:: 1.12
|
602 |
+
This argument is replaced by child_point and will be removed in a
|
603 |
+
future version.
|
604 |
+
See :ref:`deprecated-mechanics-joint-pos` for more information.
|
605 |
+
|
606 |
+
Attributes
|
607 |
+
==========
|
608 |
+
|
609 |
+
name : string
|
610 |
+
The joint's name.
|
611 |
+
parent : Body
|
612 |
+
The joint's parent body.
|
613 |
+
child : Body
|
614 |
+
The joint's child body.
|
615 |
+
coordinates : Matrix
|
616 |
+
Matrix of the joint's generalized coordinates. The default value is
|
617 |
+
``dynamicsymbols(f'q_{joint.name}')``.
|
618 |
+
speeds : Matrix
|
619 |
+
Matrix of the joint's generalized speeds. The default value is
|
620 |
+
``dynamicsymbols(f'u_{joint.name}')``.
|
621 |
+
parent_point : Point
|
622 |
+
Attachment point where the joint is fixed to the parent body.
|
623 |
+
child_point : Point
|
624 |
+
Attachment point where the joint is fixed to the child body.
|
625 |
+
parent_axis : Vector
|
626 |
+
The axis fixed in the parent frame that represents the joint.
|
627 |
+
child_axis : Vector
|
628 |
+
The axis fixed in the child frame that represents the joint.
|
629 |
+
parent_interframe : ReferenceFrame
|
630 |
+
Intermediate frame of the parent body with respect to which the joint
|
631 |
+
transformation is formulated.
|
632 |
+
child_interframe : ReferenceFrame
|
633 |
+
Intermediate frame of the child body with respect to which the joint
|
634 |
+
transformation is formulated.
|
635 |
+
joint_axis : Vector
|
636 |
+
The axis about which the rotation occurs. Note that the components of
|
637 |
+
this axis are the same in the parent_interframe and child_interframe.
|
638 |
+
kdes : Matrix
|
639 |
+
Kinematical differential equations of the joint.
|
640 |
+
|
641 |
+
Examples
|
642 |
+
=========
|
643 |
+
|
644 |
+
A single pin joint is created from two bodies and has the following basic
|
645 |
+
attributes:
|
646 |
+
|
647 |
+
>>> from sympy.physics.mechanics import Body, PinJoint
|
648 |
+
>>> parent = Body('P')
|
649 |
+
>>> parent
|
650 |
+
P
|
651 |
+
>>> child = Body('C')
|
652 |
+
>>> child
|
653 |
+
C
|
654 |
+
>>> joint = PinJoint('PC', parent, child)
|
655 |
+
>>> joint
|
656 |
+
PinJoint: PC parent: P child: C
|
657 |
+
>>> joint.name
|
658 |
+
'PC'
|
659 |
+
>>> joint.parent
|
660 |
+
P
|
661 |
+
>>> joint.child
|
662 |
+
C
|
663 |
+
>>> joint.parent_point
|
664 |
+
P_masscenter
|
665 |
+
>>> joint.child_point
|
666 |
+
C_masscenter
|
667 |
+
>>> joint.parent_axis
|
668 |
+
P_frame.x
|
669 |
+
>>> joint.child_axis
|
670 |
+
C_frame.x
|
671 |
+
>>> joint.coordinates
|
672 |
+
Matrix([[q_PC(t)]])
|
673 |
+
>>> joint.speeds
|
674 |
+
Matrix([[u_PC(t)]])
|
675 |
+
>>> joint.child.frame.ang_vel_in(joint.parent.frame)
|
676 |
+
u_PC(t)*P_frame.x
|
677 |
+
>>> joint.child.frame.dcm(joint.parent.frame)
|
678 |
+
Matrix([
|
679 |
+
[1, 0, 0],
|
680 |
+
[0, cos(q_PC(t)), sin(q_PC(t))],
|
681 |
+
[0, -sin(q_PC(t)), cos(q_PC(t))]])
|
682 |
+
>>> joint.child_point.pos_from(joint.parent_point)
|
683 |
+
0
|
684 |
+
|
685 |
+
To further demonstrate the use of the pin joint, the kinematics of simple
|
686 |
+
double pendulum that rotates about the Z axis of each connected body can be
|
687 |
+
created as follows.
|
688 |
+
|
689 |
+
>>> from sympy import symbols, trigsimp
|
690 |
+
>>> from sympy.physics.mechanics import Body, PinJoint
|
691 |
+
>>> l1, l2 = symbols('l1 l2')
|
692 |
+
|
693 |
+
First create bodies to represent the fixed ceiling and one to represent
|
694 |
+
each pendulum bob.
|
695 |
+
|
696 |
+
>>> ceiling = Body('C')
|
697 |
+
>>> upper_bob = Body('U')
|
698 |
+
>>> lower_bob = Body('L')
|
699 |
+
|
700 |
+
The first joint will connect the upper bob to the ceiling by a distance of
|
701 |
+
``l1`` and the joint axis will be about the Z axis for each body.
|
702 |
+
|
703 |
+
>>> ceiling_joint = PinJoint('P1', ceiling, upper_bob,
|
704 |
+
... child_point=-l1*upper_bob.frame.x,
|
705 |
+
... joint_axis=ceiling.frame.z)
|
706 |
+
|
707 |
+
The second joint will connect the lower bob to the upper bob by a distance
|
708 |
+
of ``l2`` and the joint axis will also be about the Z axis for each body.
|
709 |
+
|
710 |
+
>>> pendulum_joint = PinJoint('P2', upper_bob, lower_bob,
|
711 |
+
... child_point=-l2*lower_bob.frame.x,
|
712 |
+
... joint_axis=upper_bob.frame.z)
|
713 |
+
|
714 |
+
Once the joints are established the kinematics of the connected bodies can
|
715 |
+
be accessed. First the direction cosine matrices of pendulum link relative
|
716 |
+
to the ceiling are found:
|
717 |
+
|
718 |
+
>>> upper_bob.frame.dcm(ceiling.frame)
|
719 |
+
Matrix([
|
720 |
+
[ cos(q_P1(t)), sin(q_P1(t)), 0],
|
721 |
+
[-sin(q_P1(t)), cos(q_P1(t)), 0],
|
722 |
+
[ 0, 0, 1]])
|
723 |
+
>>> trigsimp(lower_bob.frame.dcm(ceiling.frame))
|
724 |
+
Matrix([
|
725 |
+
[ cos(q_P1(t) + q_P2(t)), sin(q_P1(t) + q_P2(t)), 0],
|
726 |
+
[-sin(q_P1(t) + q_P2(t)), cos(q_P1(t) + q_P2(t)), 0],
|
727 |
+
[ 0, 0, 1]])
|
728 |
+
|
729 |
+
The position of the lower bob's masscenter is found with:
|
730 |
+
|
731 |
+
>>> lower_bob.masscenter.pos_from(ceiling.masscenter)
|
732 |
+
l1*U_frame.x + l2*L_frame.x
|
733 |
+
|
734 |
+
The angular velocities of the two pendulum links can be computed with
|
735 |
+
respect to the ceiling.
|
736 |
+
|
737 |
+
>>> upper_bob.frame.ang_vel_in(ceiling.frame)
|
738 |
+
u_P1(t)*C_frame.z
|
739 |
+
>>> lower_bob.frame.ang_vel_in(ceiling.frame)
|
740 |
+
u_P1(t)*C_frame.z + u_P2(t)*U_frame.z
|
741 |
+
|
742 |
+
And finally, the linear velocities of the two pendulum bobs can be computed
|
743 |
+
with respect to the ceiling.
|
744 |
+
|
745 |
+
>>> upper_bob.masscenter.vel(ceiling.frame)
|
746 |
+
l1*u_P1(t)*U_frame.y
|
747 |
+
>>> lower_bob.masscenter.vel(ceiling.frame)
|
748 |
+
l1*u_P1(t)*U_frame.y + l2*(u_P1(t) + u_P2(t))*L_frame.y
|
749 |
+
|
750 |
+
"""
|
751 |
+
|
752 |
+
def __init__(self, name, parent, child, coordinates=None, speeds=None,
|
753 |
+
parent_point=None, child_point=None, parent_axis=None,
|
754 |
+
child_axis=None, parent_interframe=None, child_interframe=None,
|
755 |
+
joint_axis=None, parent_joint_pos=None, child_joint_pos=None):
|
756 |
+
|
757 |
+
self._joint_axis = joint_axis
|
758 |
+
super().__init__(name, parent, child, coordinates, speeds, parent_point,
|
759 |
+
child_point, parent_axis, child_axis,
|
760 |
+
parent_interframe, child_interframe, parent_joint_pos,
|
761 |
+
child_joint_pos)
|
762 |
+
|
763 |
+
def __str__(self):
|
764 |
+
return (f'PinJoint: {self.name} parent: {self.parent} '
|
765 |
+
f'child: {self.child}')
|
766 |
+
|
767 |
+
@property
|
768 |
+
def joint_axis(self):
|
769 |
+
"""Axis about which the child rotates with respect to the parent."""
|
770 |
+
return self._joint_axis
|
771 |
+
|
772 |
+
def _generate_coordinates(self, coordinate):
|
773 |
+
return self._fill_coordinate_list(coordinate, 1, 'q')
|
774 |
+
|
775 |
+
def _generate_speeds(self, speed):
|
776 |
+
return self._fill_coordinate_list(speed, 1, 'u')
|
777 |
+
|
778 |
+
def _orient_frames(self):
|
779 |
+
self._joint_axis = self._axis(self.joint_axis, self.parent_interframe)
|
780 |
+
self.child_interframe.orient_axis(
|
781 |
+
self.parent_interframe, self.joint_axis, self.coordinates[0])
|
782 |
+
|
783 |
+
def _set_angular_velocity(self):
|
784 |
+
self.child_interframe.set_ang_vel(self.parent_interframe, self.speeds[
|
785 |
+
0] * self.joint_axis.normalize())
|
786 |
+
|
787 |
+
def _set_linear_velocity(self):
|
788 |
+
self.child_point.set_pos(self.parent_point, 0)
|
789 |
+
self.parent_point.set_vel(self.parent.frame, 0)
|
790 |
+
self.child_point.set_vel(self.child.frame, 0)
|
791 |
+
self.child.masscenter.v2pt_theory(self.parent_point,
|
792 |
+
self.parent.frame, self.child.frame)
|
793 |
+
|
794 |
+
|
795 |
+
class PrismaticJoint(Joint):
|
796 |
+
"""Prismatic (Sliding) Joint.
|
797 |
+
|
798 |
+
.. image:: PrismaticJoint.svg
|
799 |
+
|
800 |
+
Explanation
|
801 |
+
===========
|
802 |
+
|
803 |
+
It is defined such that the child body translates with respect to the parent
|
804 |
+
body along the body-fixed joint axis. The location of the joint is defined
|
805 |
+
by two points, one in each body, which coincide when the generalized
|
806 |
+
coordinate is zero. The direction cosine matrix between the
|
807 |
+
parent_interframe and child_interframe is the identity matrix. Therefore,
|
808 |
+
the direction cosine matrix between the parent and child frames is fully
|
809 |
+
defined by the definition of the intermediate frames. The page on the joints
|
810 |
+
framework gives a more detailed explanation of the intermediate frames.
|
811 |
+
|
812 |
+
Parameters
|
813 |
+
==========
|
814 |
+
|
815 |
+
name : string
|
816 |
+
A unique name for the joint.
|
817 |
+
parent : Body
|
818 |
+
The parent body of joint.
|
819 |
+
child : Body
|
820 |
+
The child body of joint.
|
821 |
+
coordinates : dynamicsymbol, optional
|
822 |
+
Generalized coordinates of the joint. The default value is
|
823 |
+
``dynamicsymbols(f'q_{joint.name}')``.
|
824 |
+
speeds : dynamicsymbol, optional
|
825 |
+
Generalized speeds of joint. The default value is
|
826 |
+
``dynamicsymbols(f'u_{joint.name}')``.
|
827 |
+
parent_point : Point or Vector, optional
|
828 |
+
Attachment point where the joint is fixed to the parent body. If a
|
829 |
+
vector is provided, then the attachment point is computed by adding the
|
830 |
+
vector to the body's mass center. The default value is the parent's mass
|
831 |
+
center.
|
832 |
+
child_point : Point or Vector, optional
|
833 |
+
Attachment point where the joint is fixed to the child body. If a
|
834 |
+
vector is provided, then the attachment point is computed by adding the
|
835 |
+
vector to the body's mass center. The default value is the child's mass
|
836 |
+
center.
|
837 |
+
parent_axis : Vector, optional
|
838 |
+
.. deprecated:: 1.12
|
839 |
+
Axis fixed in the parent body which aligns with an axis fixed in the
|
840 |
+
child body. The default is the x axis of parent's reference frame.
|
841 |
+
For more information on this deprecation, see
|
842 |
+
:ref:`deprecated-mechanics-joint-axis`.
|
843 |
+
child_axis : Vector, optional
|
844 |
+
.. deprecated:: 1.12
|
845 |
+
Axis fixed in the child body which aligns with an axis fixed in the
|
846 |
+
parent body. The default is the x axis of child's reference frame.
|
847 |
+
For more information on this deprecation, see
|
848 |
+
:ref:`deprecated-mechanics-joint-axis`.
|
849 |
+
parent_interframe : ReferenceFrame, optional
|
850 |
+
Intermediate frame of the parent body with respect to which the joint
|
851 |
+
transformation is formulated. If a Vector is provided then an interframe
|
852 |
+
is created which aligns its X axis with the given vector. The default
|
853 |
+
value is the parent's own frame.
|
854 |
+
child_interframe : ReferenceFrame, optional
|
855 |
+
Intermediate frame of the child body with respect to which the joint
|
856 |
+
transformation is formulated. If a Vector is provided then an interframe
|
857 |
+
is created which aligns its X axis with the given vector. The default
|
858 |
+
value is the child's own frame.
|
859 |
+
joint_axis : Vector
|
860 |
+
The axis along which the translation occurs. Note that the components
|
861 |
+
of this axis are the same in the parent_interframe and child_interframe.
|
862 |
+
parent_joint_pos : Point or Vector, optional
|
863 |
+
.. deprecated:: 1.12
|
864 |
+
This argument is replaced by parent_point and will be removed in a
|
865 |
+
future version.
|
866 |
+
See :ref:`deprecated-mechanics-joint-pos` for more information.
|
867 |
+
child_joint_pos : Point or Vector, optional
|
868 |
+
.. deprecated:: 1.12
|
869 |
+
This argument is replaced by child_point and will be removed in a
|
870 |
+
future version.
|
871 |
+
See :ref:`deprecated-mechanics-joint-pos` for more information.
|
872 |
+
|
873 |
+
Attributes
|
874 |
+
==========
|
875 |
+
|
876 |
+
name : string
|
877 |
+
The joint's name.
|
878 |
+
parent : Body
|
879 |
+
The joint's parent body.
|
880 |
+
child : Body
|
881 |
+
The joint's child body.
|
882 |
+
coordinates : Matrix
|
883 |
+
Matrix of the joint's generalized coordinates.
|
884 |
+
speeds : Matrix
|
885 |
+
Matrix of the joint's generalized speeds.
|
886 |
+
parent_point : Point
|
887 |
+
Attachment point where the joint is fixed to the parent body.
|
888 |
+
child_point : Point
|
889 |
+
Attachment point where the joint is fixed to the child body.
|
890 |
+
parent_axis : Vector
|
891 |
+
The axis fixed in the parent frame that represents the joint.
|
892 |
+
child_axis : Vector
|
893 |
+
The axis fixed in the child frame that represents the joint.
|
894 |
+
parent_interframe : ReferenceFrame
|
895 |
+
Intermediate frame of the parent body with respect to which the joint
|
896 |
+
transformation is formulated.
|
897 |
+
child_interframe : ReferenceFrame
|
898 |
+
Intermediate frame of the child body with respect to which the joint
|
899 |
+
transformation is formulated.
|
900 |
+
kdes : Matrix
|
901 |
+
Kinematical differential equations of the joint.
|
902 |
+
|
903 |
+
Examples
|
904 |
+
=========
|
905 |
+
|
906 |
+
A single prismatic joint is created from two bodies and has the following
|
907 |
+
basic attributes:
|
908 |
+
|
909 |
+
>>> from sympy.physics.mechanics import Body, PrismaticJoint
|
910 |
+
>>> parent = Body('P')
|
911 |
+
>>> parent
|
912 |
+
P
|
913 |
+
>>> child = Body('C')
|
914 |
+
>>> child
|
915 |
+
C
|
916 |
+
>>> joint = PrismaticJoint('PC', parent, child)
|
917 |
+
>>> joint
|
918 |
+
PrismaticJoint: PC parent: P child: C
|
919 |
+
>>> joint.name
|
920 |
+
'PC'
|
921 |
+
>>> joint.parent
|
922 |
+
P
|
923 |
+
>>> joint.child
|
924 |
+
C
|
925 |
+
>>> joint.parent_point
|
926 |
+
P_masscenter
|
927 |
+
>>> joint.child_point
|
928 |
+
C_masscenter
|
929 |
+
>>> joint.parent_axis
|
930 |
+
P_frame.x
|
931 |
+
>>> joint.child_axis
|
932 |
+
C_frame.x
|
933 |
+
>>> joint.coordinates
|
934 |
+
Matrix([[q_PC(t)]])
|
935 |
+
>>> joint.speeds
|
936 |
+
Matrix([[u_PC(t)]])
|
937 |
+
>>> joint.child.frame.ang_vel_in(joint.parent.frame)
|
938 |
+
0
|
939 |
+
>>> joint.child.frame.dcm(joint.parent.frame)
|
940 |
+
Matrix([
|
941 |
+
[1, 0, 0],
|
942 |
+
[0, 1, 0],
|
943 |
+
[0, 0, 1]])
|
944 |
+
>>> joint.child_point.pos_from(joint.parent_point)
|
945 |
+
q_PC(t)*P_frame.x
|
946 |
+
|
947 |
+
To further demonstrate the use of the prismatic joint, the kinematics of two
|
948 |
+
masses sliding, one moving relative to a fixed body and the other relative
|
949 |
+
to the moving body. about the X axis of each connected body can be created
|
950 |
+
as follows.
|
951 |
+
|
952 |
+
>>> from sympy.physics.mechanics import PrismaticJoint, Body
|
953 |
+
|
954 |
+
First create bodies to represent the fixed ceiling and one to represent
|
955 |
+
a particle.
|
956 |
+
|
957 |
+
>>> wall = Body('W')
|
958 |
+
>>> Part1 = Body('P1')
|
959 |
+
>>> Part2 = Body('P2')
|
960 |
+
|
961 |
+
The first joint will connect the particle to the ceiling and the
|
962 |
+
joint axis will be about the X axis for each body.
|
963 |
+
|
964 |
+
>>> J1 = PrismaticJoint('J1', wall, Part1)
|
965 |
+
|
966 |
+
The second joint will connect the second particle to the first particle
|
967 |
+
and the joint axis will also be about the X axis for each body.
|
968 |
+
|
969 |
+
>>> J2 = PrismaticJoint('J2', Part1, Part2)
|
970 |
+
|
971 |
+
Once the joint is established the kinematics of the connected bodies can
|
972 |
+
be accessed. First the direction cosine matrices of Part relative
|
973 |
+
to the ceiling are found:
|
974 |
+
|
975 |
+
>>> Part1.dcm(wall)
|
976 |
+
Matrix([
|
977 |
+
[1, 0, 0],
|
978 |
+
[0, 1, 0],
|
979 |
+
[0, 0, 1]])
|
980 |
+
|
981 |
+
>>> Part2.dcm(wall)
|
982 |
+
Matrix([
|
983 |
+
[1, 0, 0],
|
984 |
+
[0, 1, 0],
|
985 |
+
[0, 0, 1]])
|
986 |
+
|
987 |
+
The position of the particles' masscenter is found with:
|
988 |
+
|
989 |
+
>>> Part1.masscenter.pos_from(wall.masscenter)
|
990 |
+
q_J1(t)*W_frame.x
|
991 |
+
|
992 |
+
>>> Part2.masscenter.pos_from(wall.masscenter)
|
993 |
+
q_J1(t)*W_frame.x + q_J2(t)*P1_frame.x
|
994 |
+
|
995 |
+
The angular velocities of the two particle links can be computed with
|
996 |
+
respect to the ceiling.
|
997 |
+
|
998 |
+
>>> Part1.ang_vel_in(wall)
|
999 |
+
0
|
1000 |
+
|
1001 |
+
>>> Part2.ang_vel_in(wall)
|
1002 |
+
0
|
1003 |
+
|
1004 |
+
And finally, the linear velocities of the two particles can be computed
|
1005 |
+
with respect to the ceiling.
|
1006 |
+
|
1007 |
+
>>> Part1.masscenter_vel(wall)
|
1008 |
+
u_J1(t)*W_frame.x
|
1009 |
+
|
1010 |
+
>>> Part2.masscenter.vel(wall.frame)
|
1011 |
+
u_J1(t)*W_frame.x + Derivative(q_J2(t), t)*P1_frame.x
|
1012 |
+
|
1013 |
+
"""
|
1014 |
+
|
1015 |
+
def __init__(self, name, parent, child, coordinates=None, speeds=None,
|
1016 |
+
parent_point=None, child_point=None, parent_axis=None,
|
1017 |
+
child_axis=None, parent_interframe=None, child_interframe=None,
|
1018 |
+
joint_axis=None, parent_joint_pos=None, child_joint_pos=None):
|
1019 |
+
|
1020 |
+
self._joint_axis = joint_axis
|
1021 |
+
super().__init__(name, parent, child, coordinates, speeds, parent_point,
|
1022 |
+
child_point, parent_axis, child_axis,
|
1023 |
+
parent_interframe, child_interframe, parent_joint_pos,
|
1024 |
+
child_joint_pos)
|
1025 |
+
|
1026 |
+
def __str__(self):
|
1027 |
+
return (f'PrismaticJoint: {self.name} parent: {self.parent} '
|
1028 |
+
f'child: {self.child}')
|
1029 |
+
|
1030 |
+
@property
|
1031 |
+
def joint_axis(self):
|
1032 |
+
"""Axis along which the child translates with respect to the parent."""
|
1033 |
+
return self._joint_axis
|
1034 |
+
|
1035 |
+
def _generate_coordinates(self, coordinate):
|
1036 |
+
return self._fill_coordinate_list(coordinate, 1, 'q')
|
1037 |
+
|
1038 |
+
def _generate_speeds(self, speed):
|
1039 |
+
return self._fill_coordinate_list(speed, 1, 'u')
|
1040 |
+
|
1041 |
+
def _orient_frames(self):
|
1042 |
+
self._joint_axis = self._axis(self.joint_axis, self.parent_interframe)
|
1043 |
+
self.child_interframe.orient_axis(
|
1044 |
+
self.parent_interframe, self.joint_axis, 0)
|
1045 |
+
|
1046 |
+
def _set_angular_velocity(self):
|
1047 |
+
self.child_interframe.set_ang_vel(self.parent_interframe, 0)
|
1048 |
+
|
1049 |
+
def _set_linear_velocity(self):
|
1050 |
+
axis = self.joint_axis.normalize()
|
1051 |
+
self.child_point.set_pos(self.parent_point, self.coordinates[0] * axis)
|
1052 |
+
self.parent_point.set_vel(self.parent.frame, 0)
|
1053 |
+
self.child_point.set_vel(self.child.frame, 0)
|
1054 |
+
self.child_point.set_vel(self.parent.frame, self.speeds[0] * axis)
|
1055 |
+
self.child.masscenter.set_vel(self.parent.frame, self.speeds[0] * axis)
|
1056 |
+
|
1057 |
+
|
1058 |
+
class CylindricalJoint(Joint):
|
1059 |
+
"""Cylindrical Joint.
|
1060 |
+
|
1061 |
+
.. image:: CylindricalJoint.svg
|
1062 |
+
:align: center
|
1063 |
+
:width: 600
|
1064 |
+
|
1065 |
+
Explanation
|
1066 |
+
===========
|
1067 |
+
|
1068 |
+
A cylindrical joint is defined such that the child body both rotates about
|
1069 |
+
and translates along the body-fixed joint axis with respect to the parent
|
1070 |
+
body. The joint axis is both the rotation axis and translation axis. The
|
1071 |
+
location of the joint is defined by two points, one in each body, which
|
1072 |
+
coincide when the generalized coordinate corresponding to the translation is
|
1073 |
+
zero. The direction cosine matrix between the child interframe and parent
|
1074 |
+
interframe is formed using a simple rotation about the joint axis. The page
|
1075 |
+
on the joints framework gives a more detailed explanation of the
|
1076 |
+
intermediate frames.
|
1077 |
+
|
1078 |
+
Parameters
|
1079 |
+
==========
|
1080 |
+
|
1081 |
+
name : string
|
1082 |
+
A unique name for the joint.
|
1083 |
+
parent : Body
|
1084 |
+
The parent body of joint.
|
1085 |
+
child : Body
|
1086 |
+
The child body of joint.
|
1087 |
+
rotation_coordinate : dynamicsymbol, optional
|
1088 |
+
Generalized coordinate corresponding to the rotation angle. The default
|
1089 |
+
value is ``dynamicsymbols(f'q0_{joint.name}')``.
|
1090 |
+
translation_coordinate : dynamicsymbol, optional
|
1091 |
+
Generalized coordinate corresponding to the translation distance. The
|
1092 |
+
default value is ``dynamicsymbols(f'q1_{joint.name}')``.
|
1093 |
+
rotation_speed : dynamicsymbol, optional
|
1094 |
+
Generalized speed corresponding to the angular velocity. The default
|
1095 |
+
value is ``dynamicsymbols(f'u0_{joint.name}')``.
|
1096 |
+
translation_speed : dynamicsymbol, optional
|
1097 |
+
Generalized speed corresponding to the translation velocity. The default
|
1098 |
+
value is ``dynamicsymbols(f'u1_{joint.name}')``.
|
1099 |
+
parent_point : Point or Vector, optional
|
1100 |
+
Attachment point where the joint is fixed to the parent body. If a
|
1101 |
+
vector is provided, then the attachment point is computed by adding the
|
1102 |
+
vector to the body's mass center. The default value is the parent's mass
|
1103 |
+
center.
|
1104 |
+
child_point : Point or Vector, optional
|
1105 |
+
Attachment point where the joint is fixed to the child body. If a
|
1106 |
+
vector is provided, then the attachment point is computed by adding the
|
1107 |
+
vector to the body's mass center. The default value is the child's mass
|
1108 |
+
center.
|
1109 |
+
parent_interframe : ReferenceFrame, optional
|
1110 |
+
Intermediate frame of the parent body with respect to which the joint
|
1111 |
+
transformation is formulated. If a Vector is provided then an interframe
|
1112 |
+
is created which aligns its X axis with the given vector. The default
|
1113 |
+
value is the parent's own frame.
|
1114 |
+
child_interframe : ReferenceFrame, optional
|
1115 |
+
Intermediate frame of the child body with respect to which the joint
|
1116 |
+
transformation is formulated. If a Vector is provided then an interframe
|
1117 |
+
is created which aligns its X axis with the given vector. The default
|
1118 |
+
value is the child's own frame.
|
1119 |
+
joint_axis : Vector, optional
|
1120 |
+
The rotation as well as translation axis. Note that the components of
|
1121 |
+
this axis are the same in the parent_interframe and child_interframe.
|
1122 |
+
|
1123 |
+
Attributes
|
1124 |
+
==========
|
1125 |
+
|
1126 |
+
name : string
|
1127 |
+
The joint's name.
|
1128 |
+
parent : Body
|
1129 |
+
The joint's parent body.
|
1130 |
+
child : Body
|
1131 |
+
The joint's child body.
|
1132 |
+
rotation_coordinate : dynamicsymbol
|
1133 |
+
Generalized coordinate corresponding to the rotation angle.
|
1134 |
+
translation_coordinate : dynamicsymbol
|
1135 |
+
Generalized coordinate corresponding to the translation distance.
|
1136 |
+
rotation_speed : dynamicsymbol
|
1137 |
+
Generalized speed corresponding to the angular velocity.
|
1138 |
+
translation_speed : dynamicsymbol
|
1139 |
+
Generalized speed corresponding to the translation velocity.
|
1140 |
+
coordinates : Matrix
|
1141 |
+
Matrix of the joint's generalized coordinates.
|
1142 |
+
speeds : Matrix
|
1143 |
+
Matrix of the joint's generalized speeds.
|
1144 |
+
parent_point : Point
|
1145 |
+
Attachment point where the joint is fixed to the parent body.
|
1146 |
+
child_point : Point
|
1147 |
+
Attachment point where the joint is fixed to the child body.
|
1148 |
+
parent_interframe : ReferenceFrame
|
1149 |
+
Intermediate frame of the parent body with respect to which the joint
|
1150 |
+
transformation is formulated.
|
1151 |
+
child_interframe : ReferenceFrame
|
1152 |
+
Intermediate frame of the child body with respect to which the joint
|
1153 |
+
transformation is formulated.
|
1154 |
+
kdes : Matrix
|
1155 |
+
Kinematical differential equations of the joint.
|
1156 |
+
joint_axis : Vector
|
1157 |
+
The axis of rotation and translation.
|
1158 |
+
|
1159 |
+
Examples
|
1160 |
+
=========
|
1161 |
+
|
1162 |
+
A single cylindrical joint is created between two bodies and has the
|
1163 |
+
following basic attributes:
|
1164 |
+
|
1165 |
+
>>> from sympy.physics.mechanics import Body, CylindricalJoint
|
1166 |
+
>>> parent = Body('P')
|
1167 |
+
>>> parent
|
1168 |
+
P
|
1169 |
+
>>> child = Body('C')
|
1170 |
+
>>> child
|
1171 |
+
C
|
1172 |
+
>>> joint = CylindricalJoint('PC', parent, child)
|
1173 |
+
>>> joint
|
1174 |
+
CylindricalJoint: PC parent: P child: C
|
1175 |
+
>>> joint.name
|
1176 |
+
'PC'
|
1177 |
+
>>> joint.parent
|
1178 |
+
P
|
1179 |
+
>>> joint.child
|
1180 |
+
C
|
1181 |
+
>>> joint.parent_point
|
1182 |
+
P_masscenter
|
1183 |
+
>>> joint.child_point
|
1184 |
+
C_masscenter
|
1185 |
+
>>> joint.parent_axis
|
1186 |
+
P_frame.x
|
1187 |
+
>>> joint.child_axis
|
1188 |
+
C_frame.x
|
1189 |
+
>>> joint.coordinates
|
1190 |
+
Matrix([
|
1191 |
+
[q0_PC(t)],
|
1192 |
+
[q1_PC(t)]])
|
1193 |
+
>>> joint.speeds
|
1194 |
+
Matrix([
|
1195 |
+
[u0_PC(t)],
|
1196 |
+
[u1_PC(t)]])
|
1197 |
+
>>> joint.child.frame.ang_vel_in(joint.parent.frame)
|
1198 |
+
u0_PC(t)*P_frame.x
|
1199 |
+
>>> joint.child.frame.dcm(joint.parent.frame)
|
1200 |
+
Matrix([
|
1201 |
+
[1, 0, 0],
|
1202 |
+
[0, cos(q0_PC(t)), sin(q0_PC(t))],
|
1203 |
+
[0, -sin(q0_PC(t)), cos(q0_PC(t))]])
|
1204 |
+
>>> joint.child_point.pos_from(joint.parent_point)
|
1205 |
+
q1_PC(t)*P_frame.x
|
1206 |
+
>>> child.masscenter.vel(parent.frame)
|
1207 |
+
u1_PC(t)*P_frame.x
|
1208 |
+
|
1209 |
+
To further demonstrate the use of the cylindrical joint, the kinematics of
|
1210 |
+
two cylindrical joints perpendicular to each other can be created as follows.
|
1211 |
+
|
1212 |
+
>>> from sympy import symbols
|
1213 |
+
>>> from sympy.physics.mechanics import Body, CylindricalJoint
|
1214 |
+
>>> r, l, w = symbols('r l w')
|
1215 |
+
|
1216 |
+
First create bodies to represent the fixed floor with a fixed pole on it.
|
1217 |
+
The second body represents a freely moving tube around that pole. The third
|
1218 |
+
body represents a solid flag freely translating along and rotating around
|
1219 |
+
the Y axis of the tube.
|
1220 |
+
|
1221 |
+
>>> floor = Body('floor')
|
1222 |
+
>>> tube = Body('tube')
|
1223 |
+
>>> flag = Body('flag')
|
1224 |
+
|
1225 |
+
The first joint will connect the first tube to the floor with it translating
|
1226 |
+
along and rotating around the Z axis of both bodies.
|
1227 |
+
|
1228 |
+
>>> floor_joint = CylindricalJoint('C1', floor, tube, joint_axis=floor.z)
|
1229 |
+
|
1230 |
+
The second joint will connect the tube perpendicular to the flag along the Y
|
1231 |
+
axis of both the tube and the flag, with the joint located at a distance
|
1232 |
+
``r`` from the tube's center of mass and a combination of the distances
|
1233 |
+
``l`` and ``w`` from the flag's center of mass.
|
1234 |
+
|
1235 |
+
>>> flag_joint = CylindricalJoint('C2', tube, flag,
|
1236 |
+
... parent_point=r * tube.y,
|
1237 |
+
... child_point=-w * flag.y + l * flag.z,
|
1238 |
+
... joint_axis=tube.y)
|
1239 |
+
|
1240 |
+
Once the joints are established the kinematics of the connected bodies can
|
1241 |
+
be accessed. First the direction cosine matrices of both the body and the
|
1242 |
+
flag relative to the floor are found:
|
1243 |
+
|
1244 |
+
>>> tube.dcm(floor)
|
1245 |
+
Matrix([
|
1246 |
+
[ cos(q0_C1(t)), sin(q0_C1(t)), 0],
|
1247 |
+
[-sin(q0_C1(t)), cos(q0_C1(t)), 0],
|
1248 |
+
[ 0, 0, 1]])
|
1249 |
+
>>> flag.dcm(floor)
|
1250 |
+
Matrix([
|
1251 |
+
[cos(q0_C1(t))*cos(q0_C2(t)), sin(q0_C1(t))*cos(q0_C2(t)), -sin(q0_C2(t))],
|
1252 |
+
[ -sin(q0_C1(t)), cos(q0_C1(t)), 0],
|
1253 |
+
[sin(q0_C2(t))*cos(q0_C1(t)), sin(q0_C1(t))*sin(q0_C2(t)), cos(q0_C2(t))]])
|
1254 |
+
|
1255 |
+
The position of the flag's center of mass is found with:
|
1256 |
+
|
1257 |
+
>>> flag.masscenter.pos_from(floor.masscenter)
|
1258 |
+
q1_C1(t)*floor_frame.z + (r + q1_C2(t))*tube_frame.y + w*flag_frame.y - l*flag_frame.z
|
1259 |
+
|
1260 |
+
The angular velocities of the two tubes can be computed with respect to the
|
1261 |
+
floor.
|
1262 |
+
|
1263 |
+
>>> tube.ang_vel_in(floor)
|
1264 |
+
u0_C1(t)*floor_frame.z
|
1265 |
+
>>> flag.ang_vel_in(floor)
|
1266 |
+
u0_C1(t)*floor_frame.z + u0_C2(t)*tube_frame.y
|
1267 |
+
|
1268 |
+
Finally, the linear velocities of the two tube centers of mass can be
|
1269 |
+
computed with respect to the floor, while expressed in the tube's frame.
|
1270 |
+
|
1271 |
+
>>> tube.masscenter.vel(floor.frame).to_matrix(tube.frame)
|
1272 |
+
Matrix([
|
1273 |
+
[ 0],
|
1274 |
+
[ 0],
|
1275 |
+
[u1_C1(t)]])
|
1276 |
+
>>> flag.masscenter.vel(floor.frame).to_matrix(tube.frame).simplify()
|
1277 |
+
Matrix([
|
1278 |
+
[-l*u0_C2(t)*cos(q0_C2(t)) - r*u0_C1(t) - w*u0_C1(t) - q1_C2(t)*u0_C1(t)],
|
1279 |
+
[ -l*u0_C1(t)*sin(q0_C2(t)) + Derivative(q1_C2(t), t)],
|
1280 |
+
[ l*u0_C2(t)*sin(q0_C2(t)) + u1_C1(t)]])
|
1281 |
+
|
1282 |
+
"""
|
1283 |
+
|
1284 |
+
def __init__(self, name, parent, child, rotation_coordinate=None,
|
1285 |
+
translation_coordinate=None, rotation_speed=None,
|
1286 |
+
translation_speed=None, parent_point=None, child_point=None,
|
1287 |
+
parent_interframe=None, child_interframe=None,
|
1288 |
+
joint_axis=None):
|
1289 |
+
self._joint_axis = joint_axis
|
1290 |
+
coordinates = (rotation_coordinate, translation_coordinate)
|
1291 |
+
speeds = (rotation_speed, translation_speed)
|
1292 |
+
super().__init__(name, parent, child, coordinates, speeds,
|
1293 |
+
parent_point, child_point,
|
1294 |
+
parent_interframe=parent_interframe,
|
1295 |
+
child_interframe=child_interframe)
|
1296 |
+
|
1297 |
+
def __str__(self):
|
1298 |
+
return (f'CylindricalJoint: {self.name} parent: {self.parent} '
|
1299 |
+
f'child: {self.child}')
|
1300 |
+
|
1301 |
+
@property
|
1302 |
+
def joint_axis(self):
|
1303 |
+
"""Axis about and along which the rotation and translation occurs."""
|
1304 |
+
return self._joint_axis
|
1305 |
+
|
1306 |
+
@property
|
1307 |
+
def rotation_coordinate(self):
|
1308 |
+
"""Generalized coordinate corresponding to the rotation angle."""
|
1309 |
+
return self.coordinates[0]
|
1310 |
+
|
1311 |
+
@property
|
1312 |
+
def translation_coordinate(self):
|
1313 |
+
"""Generalized coordinate corresponding to the translation distance."""
|
1314 |
+
return self.coordinates[1]
|
1315 |
+
|
1316 |
+
@property
|
1317 |
+
def rotation_speed(self):
|
1318 |
+
"""Generalized speed corresponding to the angular velocity."""
|
1319 |
+
return self.speeds[0]
|
1320 |
+
|
1321 |
+
@property
|
1322 |
+
def translation_speed(self):
|
1323 |
+
"""Generalized speed corresponding to the translation velocity."""
|
1324 |
+
return self.speeds[1]
|
1325 |
+
|
1326 |
+
def _generate_coordinates(self, coordinates):
|
1327 |
+
return self._fill_coordinate_list(coordinates, 2, 'q')
|
1328 |
+
|
1329 |
+
def _generate_speeds(self, speeds):
|
1330 |
+
return self._fill_coordinate_list(speeds, 2, 'u')
|
1331 |
+
|
1332 |
+
def _orient_frames(self):
|
1333 |
+
self._joint_axis = self._axis(self.joint_axis, self.parent_interframe)
|
1334 |
+
self.child_interframe.orient_axis(
|
1335 |
+
self.parent_interframe, self.joint_axis, self.rotation_coordinate)
|
1336 |
+
|
1337 |
+
def _set_angular_velocity(self):
|
1338 |
+
self.child_interframe.set_ang_vel(
|
1339 |
+
self.parent_interframe,
|
1340 |
+
self.rotation_speed * self.joint_axis.normalize())
|
1341 |
+
|
1342 |
+
def _set_linear_velocity(self):
|
1343 |
+
self.child_point.set_pos(
|
1344 |
+
self.parent_point,
|
1345 |
+
self.translation_coordinate * self.joint_axis.normalize())
|
1346 |
+
self.parent_point.set_vel(self.parent.frame, 0)
|
1347 |
+
self.child_point.set_vel(self.child.frame, 0)
|
1348 |
+
self.child_point.set_vel(
|
1349 |
+
self.parent.frame,
|
1350 |
+
self.translation_speed * self.joint_axis.normalize())
|
1351 |
+
self.child.masscenter.v2pt_theory(self.child_point, self.parent.frame,
|
1352 |
+
self.child_interframe)
|
1353 |
+
|
1354 |
+
|
1355 |
+
class PlanarJoint(Joint):
|
1356 |
+
"""Planar Joint.
|
1357 |
+
|
1358 |
+
.. image:: PlanarJoint.svg
|
1359 |
+
:align: center
|
1360 |
+
:width: 800
|
1361 |
+
|
1362 |
+
Explanation
|
1363 |
+
===========
|
1364 |
+
|
1365 |
+
A planar joint is defined such that the child body translates over a fixed
|
1366 |
+
plane of the parent body as well as rotate about the rotation axis, which
|
1367 |
+
is perpendicular to that plane. The origin of this plane is the
|
1368 |
+
``parent_point`` and the plane is spanned by two nonparallel planar vectors.
|
1369 |
+
The location of the ``child_point`` is based on the planar vectors
|
1370 |
+
($\\vec{v}_1$, $\\vec{v}_2$) and generalized coordinates ($q_1$, $q_2$),
|
1371 |
+
i.e. $\\vec{r} = q_1 \\hat{v}_1 + q_2 \\hat{v}_2$. The direction cosine
|
1372 |
+
matrix between the ``child_interframe`` and ``parent_interframe`` is formed
|
1373 |
+
using a simple rotation ($q_0$) about the rotation axis.
|
1374 |
+
|
1375 |
+
In order to simplify the definition of the ``PlanarJoint``, the
|
1376 |
+
``rotation_axis`` and ``planar_vectors`` are set to be the unit vectors of
|
1377 |
+
the ``parent_interframe`` according to the table below. This ensures that
|
1378 |
+
you can only define these vectors by creating a separate frame and supplying
|
1379 |
+
that as the interframe. If you however would only like to supply the normals
|
1380 |
+
of the plane with respect to the parent and child bodies, then you can also
|
1381 |
+
supply those to the ``parent_interframe`` and ``child_interframe``
|
1382 |
+
arguments. An example of both of these cases is in the examples section
|
1383 |
+
below and the page on the joints framework provides a more detailed
|
1384 |
+
explanation of the intermediate frames.
|
1385 |
+
|
1386 |
+
.. list-table::
|
1387 |
+
|
1388 |
+
* - ``rotation_axis``
|
1389 |
+
- ``parent_interframe.x``
|
1390 |
+
* - ``planar_vectors[0]``
|
1391 |
+
- ``parent_interframe.y``
|
1392 |
+
* - ``planar_vectors[1]``
|
1393 |
+
- ``parent_interframe.z``
|
1394 |
+
|
1395 |
+
Parameters
|
1396 |
+
==========
|
1397 |
+
|
1398 |
+
name : string
|
1399 |
+
A unique name for the joint.
|
1400 |
+
parent : Body
|
1401 |
+
The parent body of joint.
|
1402 |
+
child : Body
|
1403 |
+
The child body of joint.
|
1404 |
+
rotation_coordinate : dynamicsymbol, optional
|
1405 |
+
Generalized coordinate corresponding to the rotation angle. The default
|
1406 |
+
value is ``dynamicsymbols(f'q0_{joint.name}')``.
|
1407 |
+
planar_coordinates : iterable of dynamicsymbols, optional
|
1408 |
+
Two generalized coordinates used for the planar translation. The default
|
1409 |
+
value is ``dynamicsymbols(f'q1_{joint.name} q2_{joint.name}')``.
|
1410 |
+
rotation_speed : dynamicsymbol, optional
|
1411 |
+
Generalized speed corresponding to the angular velocity. The default
|
1412 |
+
value is ``dynamicsymbols(f'u0_{joint.name}')``.
|
1413 |
+
planar_speeds : dynamicsymbols, optional
|
1414 |
+
Two generalized speeds used for the planar translation velocity. The
|
1415 |
+
default value is ``dynamicsymbols(f'u1_{joint.name} u2_{joint.name}')``.
|
1416 |
+
parent_point : Point or Vector, optional
|
1417 |
+
Attachment point where the joint is fixed to the parent body. If a
|
1418 |
+
vector is provided, then the attachment point is computed by adding the
|
1419 |
+
vector to the body's mass center. The default value is the parent's mass
|
1420 |
+
center.
|
1421 |
+
child_point : Point or Vector, optional
|
1422 |
+
Attachment point where the joint is fixed to the child body. If a
|
1423 |
+
vector is provided, then the attachment point is computed by adding the
|
1424 |
+
vector to the body's mass center. The default value is the child's mass
|
1425 |
+
center.
|
1426 |
+
parent_interframe : ReferenceFrame, optional
|
1427 |
+
Intermediate frame of the parent body with respect to which the joint
|
1428 |
+
transformation is formulated. If a Vector is provided then an interframe
|
1429 |
+
is created which aligns its X axis with the given vector. The default
|
1430 |
+
value is the parent's own frame.
|
1431 |
+
child_interframe : ReferenceFrame, optional
|
1432 |
+
Intermediate frame of the child body with respect to which the joint
|
1433 |
+
transformation is formulated. If a Vector is provided then an interframe
|
1434 |
+
is created which aligns its X axis with the given vector. The default
|
1435 |
+
value is the child's own frame.
|
1436 |
+
|
1437 |
+
Attributes
|
1438 |
+
==========
|
1439 |
+
|
1440 |
+
name : string
|
1441 |
+
The joint's name.
|
1442 |
+
parent : Body
|
1443 |
+
The joint's parent body.
|
1444 |
+
child : Body
|
1445 |
+
The joint's child body.
|
1446 |
+
rotation_coordinate : dynamicsymbol
|
1447 |
+
Generalized coordinate corresponding to the rotation angle.
|
1448 |
+
planar_coordinates : Matrix
|
1449 |
+
Two generalized coordinates used for the planar translation.
|
1450 |
+
rotation_speed : dynamicsymbol
|
1451 |
+
Generalized speed corresponding to the angular velocity.
|
1452 |
+
planar_speeds : Matrix
|
1453 |
+
Two generalized speeds used for the planar translation velocity.
|
1454 |
+
coordinates : Matrix
|
1455 |
+
Matrix of the joint's generalized coordinates.
|
1456 |
+
speeds : Matrix
|
1457 |
+
Matrix of the joint's generalized speeds.
|
1458 |
+
parent_point : Point
|
1459 |
+
Attachment point where the joint is fixed to the parent body.
|
1460 |
+
child_point : Point
|
1461 |
+
Attachment point where the joint is fixed to the child body.
|
1462 |
+
parent_interframe : ReferenceFrame
|
1463 |
+
Intermediate frame of the parent body with respect to which the joint
|
1464 |
+
transformation is formulated.
|
1465 |
+
child_interframe : ReferenceFrame
|
1466 |
+
Intermediate frame of the child body with respect to which the joint
|
1467 |
+
transformation is formulated.
|
1468 |
+
kdes : Matrix
|
1469 |
+
Kinematical differential equations of the joint.
|
1470 |
+
rotation_axis : Vector
|
1471 |
+
The axis about which the rotation occurs.
|
1472 |
+
planar_vectors : list
|
1473 |
+
The vectors that describe the planar translation directions.
|
1474 |
+
|
1475 |
+
Examples
|
1476 |
+
=========
|
1477 |
+
|
1478 |
+
A single planar joint is created between two bodies and has the following
|
1479 |
+
basic attributes:
|
1480 |
+
|
1481 |
+
>>> from sympy.physics.mechanics import Body, PlanarJoint
|
1482 |
+
>>> parent = Body('P')
|
1483 |
+
>>> parent
|
1484 |
+
P
|
1485 |
+
>>> child = Body('C')
|
1486 |
+
>>> child
|
1487 |
+
C
|
1488 |
+
>>> joint = PlanarJoint('PC', parent, child)
|
1489 |
+
>>> joint
|
1490 |
+
PlanarJoint: PC parent: P child: C
|
1491 |
+
>>> joint.name
|
1492 |
+
'PC'
|
1493 |
+
>>> joint.parent
|
1494 |
+
P
|
1495 |
+
>>> joint.child
|
1496 |
+
C
|
1497 |
+
>>> joint.parent_point
|
1498 |
+
P_masscenter
|
1499 |
+
>>> joint.child_point
|
1500 |
+
C_masscenter
|
1501 |
+
>>> joint.rotation_axis
|
1502 |
+
P_frame.x
|
1503 |
+
>>> joint.planar_vectors
|
1504 |
+
[P_frame.y, P_frame.z]
|
1505 |
+
>>> joint.rotation_coordinate
|
1506 |
+
q0_PC(t)
|
1507 |
+
>>> joint.planar_coordinates
|
1508 |
+
Matrix([
|
1509 |
+
[q1_PC(t)],
|
1510 |
+
[q2_PC(t)]])
|
1511 |
+
>>> joint.coordinates
|
1512 |
+
Matrix([
|
1513 |
+
[q0_PC(t)],
|
1514 |
+
[q1_PC(t)],
|
1515 |
+
[q2_PC(t)]])
|
1516 |
+
>>> joint.rotation_speed
|
1517 |
+
u0_PC(t)
|
1518 |
+
>>> joint.planar_speeds
|
1519 |
+
Matrix([
|
1520 |
+
[u1_PC(t)],
|
1521 |
+
[u2_PC(t)]])
|
1522 |
+
>>> joint.speeds
|
1523 |
+
Matrix([
|
1524 |
+
[u0_PC(t)],
|
1525 |
+
[u1_PC(t)],
|
1526 |
+
[u2_PC(t)]])
|
1527 |
+
>>> joint.child.frame.ang_vel_in(joint.parent.frame)
|
1528 |
+
u0_PC(t)*P_frame.x
|
1529 |
+
>>> joint.child.frame.dcm(joint.parent.frame)
|
1530 |
+
Matrix([
|
1531 |
+
[1, 0, 0],
|
1532 |
+
[0, cos(q0_PC(t)), sin(q0_PC(t))],
|
1533 |
+
[0, -sin(q0_PC(t)), cos(q0_PC(t))]])
|
1534 |
+
>>> joint.child_point.pos_from(joint.parent_point)
|
1535 |
+
q1_PC(t)*P_frame.y + q2_PC(t)*P_frame.z
|
1536 |
+
>>> child.masscenter.vel(parent.frame)
|
1537 |
+
u1_PC(t)*P_frame.y + u2_PC(t)*P_frame.z
|
1538 |
+
|
1539 |
+
To further demonstrate the use of the planar joint, the kinematics of a
|
1540 |
+
block sliding on a slope, can be created as follows.
|
1541 |
+
|
1542 |
+
>>> from sympy import symbols
|
1543 |
+
>>> from sympy.physics.mechanics import PlanarJoint, Body, ReferenceFrame
|
1544 |
+
>>> a, d, h = symbols('a d h')
|
1545 |
+
|
1546 |
+
First create bodies to represent the slope and the block.
|
1547 |
+
|
1548 |
+
>>> ground = Body('G')
|
1549 |
+
>>> block = Body('B')
|
1550 |
+
|
1551 |
+
To define the slope you can either define the plane by specifying the
|
1552 |
+
``planar_vectors`` or/and the ``rotation_axis``. However it is advisable to
|
1553 |
+
create a rotated intermediate frame, so that the ``parent_vectors`` and
|
1554 |
+
``rotation_axis`` will be the unit vectors of this intermediate frame.
|
1555 |
+
|
1556 |
+
>>> slope = ReferenceFrame('A')
|
1557 |
+
>>> slope.orient_axis(ground.frame, ground.y, a)
|
1558 |
+
|
1559 |
+
The planar joint can be created using these bodies and intermediate frame.
|
1560 |
+
We can specify the origin of the slope to be ``d`` above the slope's center
|
1561 |
+
of mass and the block's center of mass to be a distance ``h`` above the
|
1562 |
+
slope's surface. Note that we can specify the normal of the plane using the
|
1563 |
+
rotation axis argument.
|
1564 |
+
|
1565 |
+
>>> joint = PlanarJoint('PC', ground, block, parent_point=d * ground.x,
|
1566 |
+
... child_point=-h * block.x, parent_interframe=slope)
|
1567 |
+
|
1568 |
+
Once the joint is established the kinematics of the bodies can be accessed.
|
1569 |
+
First the ``rotation_axis``, which is normal to the plane and the
|
1570 |
+
``plane_vectors``, can be found.
|
1571 |
+
|
1572 |
+
>>> joint.rotation_axis
|
1573 |
+
A.x
|
1574 |
+
>>> joint.planar_vectors
|
1575 |
+
[A.y, A.z]
|
1576 |
+
|
1577 |
+
The direction cosine matrix of the block with respect to the ground can be
|
1578 |
+
found with:
|
1579 |
+
|
1580 |
+
>>> block.dcm(ground)
|
1581 |
+
Matrix([
|
1582 |
+
[ cos(a), 0, -sin(a)],
|
1583 |
+
[sin(a)*sin(q0_PC(t)), cos(q0_PC(t)), sin(q0_PC(t))*cos(a)],
|
1584 |
+
[sin(a)*cos(q0_PC(t)), -sin(q0_PC(t)), cos(a)*cos(q0_PC(t))]])
|
1585 |
+
|
1586 |
+
The angular velocity of the block can be computed with respect to the
|
1587 |
+
ground.
|
1588 |
+
|
1589 |
+
>>> block.ang_vel_in(ground)
|
1590 |
+
u0_PC(t)*A.x
|
1591 |
+
|
1592 |
+
The position of the block's center of mass can be found with:
|
1593 |
+
|
1594 |
+
>>> block.masscenter.pos_from(ground.masscenter)
|
1595 |
+
d*G_frame.x + h*B_frame.x + q1_PC(t)*A.y + q2_PC(t)*A.z
|
1596 |
+
|
1597 |
+
Finally, the linear velocity of the block's center of mass can be
|
1598 |
+
computed with respect to the ground.
|
1599 |
+
|
1600 |
+
>>> block.masscenter.vel(ground.frame)
|
1601 |
+
u1_PC(t)*A.y + u2_PC(t)*A.z
|
1602 |
+
|
1603 |
+
In some cases it could be your preference to only define the normals of the
|
1604 |
+
plane with respect to both bodies. This can most easily be done by supplying
|
1605 |
+
vectors to the ``interframe`` arguments. What will happen in this case is
|
1606 |
+
that an interframe will be created with its ``x`` axis aligned with the
|
1607 |
+
provided vector. For a further explanation of how this is done see the notes
|
1608 |
+
of the ``Joint`` class. In the code below, the above example (with the block
|
1609 |
+
on the slope) is recreated by supplying vectors to the interframe arguments.
|
1610 |
+
Note that the previously described option is however more computationally
|
1611 |
+
efficient, because the algorithm now has to compute the rotation angle
|
1612 |
+
between the provided vector and the 'x' axis.
|
1613 |
+
|
1614 |
+
>>> from sympy import symbols, cos, sin
|
1615 |
+
>>> from sympy.physics.mechanics import PlanarJoint, Body
|
1616 |
+
>>> a, d, h = symbols('a d h')
|
1617 |
+
>>> ground = Body('G')
|
1618 |
+
>>> block = Body('B')
|
1619 |
+
>>> joint = PlanarJoint(
|
1620 |
+
... 'PC', ground, block, parent_point=d * ground.x,
|
1621 |
+
... child_point=-h * block.x, child_interframe=block.x,
|
1622 |
+
... parent_interframe=cos(a) * ground.x + sin(a) * ground.z)
|
1623 |
+
>>> block.dcm(ground).simplify()
|
1624 |
+
Matrix([
|
1625 |
+
[ cos(a), 0, sin(a)],
|
1626 |
+
[-sin(a)*sin(q0_PC(t)), cos(q0_PC(t)), sin(q0_PC(t))*cos(a)],
|
1627 |
+
[-sin(a)*cos(q0_PC(t)), -sin(q0_PC(t)), cos(a)*cos(q0_PC(t))]])
|
1628 |
+
|
1629 |
+
"""
|
1630 |
+
|
1631 |
+
def __init__(self, name, parent, child, rotation_coordinate=None,
|
1632 |
+
planar_coordinates=None, rotation_speed=None,
|
1633 |
+
planar_speeds=None, parent_point=None, child_point=None,
|
1634 |
+
parent_interframe=None, child_interframe=None):
|
1635 |
+
# A ready to merge implementation of setting the planar_vectors and
|
1636 |
+
# rotation_axis was added and removed in PR #24046
|
1637 |
+
coordinates = (rotation_coordinate, planar_coordinates)
|
1638 |
+
speeds = (rotation_speed, planar_speeds)
|
1639 |
+
super().__init__(name, parent, child, coordinates, speeds,
|
1640 |
+
parent_point, child_point,
|
1641 |
+
parent_interframe=parent_interframe,
|
1642 |
+
child_interframe=child_interframe)
|
1643 |
+
|
1644 |
+
def __str__(self):
|
1645 |
+
return (f'PlanarJoint: {self.name} parent: {self.parent} '
|
1646 |
+
f'child: {self.child}')
|
1647 |
+
|
1648 |
+
@property
|
1649 |
+
def rotation_coordinate(self):
|
1650 |
+
"""Generalized coordinate corresponding to the rotation angle."""
|
1651 |
+
return self.coordinates[0]
|
1652 |
+
|
1653 |
+
@property
|
1654 |
+
def planar_coordinates(self):
|
1655 |
+
"""Two generalized coordinates used for the planar translation."""
|
1656 |
+
return self.coordinates[1:, 0]
|
1657 |
+
|
1658 |
+
@property
|
1659 |
+
def rotation_speed(self):
|
1660 |
+
"""Generalized speed corresponding to the angular velocity."""
|
1661 |
+
return self.speeds[0]
|
1662 |
+
|
1663 |
+
@property
|
1664 |
+
def planar_speeds(self):
|
1665 |
+
"""Two generalized speeds used for the planar translation velocity."""
|
1666 |
+
return self.speeds[1:, 0]
|
1667 |
+
|
1668 |
+
@property
|
1669 |
+
def rotation_axis(self):
|
1670 |
+
"""The axis about which the rotation occurs."""
|
1671 |
+
return self.parent_interframe.x
|
1672 |
+
|
1673 |
+
@property
|
1674 |
+
def planar_vectors(self):
|
1675 |
+
"""The vectors that describe the planar translation directions."""
|
1676 |
+
return [self.parent_interframe.y, self.parent_interframe.z]
|
1677 |
+
|
1678 |
+
def _generate_coordinates(self, coordinates):
|
1679 |
+
rotation_speed = self._fill_coordinate_list(coordinates[0], 1, 'q',
|
1680 |
+
number_single=True)
|
1681 |
+
planar_speeds = self._fill_coordinate_list(coordinates[1], 2, 'q', 1)
|
1682 |
+
return rotation_speed.col_join(planar_speeds)
|
1683 |
+
|
1684 |
+
def _generate_speeds(self, speeds):
|
1685 |
+
rotation_speed = self._fill_coordinate_list(speeds[0], 1, 'u',
|
1686 |
+
number_single=True)
|
1687 |
+
planar_speeds = self._fill_coordinate_list(speeds[1], 2, 'u', 1)
|
1688 |
+
return rotation_speed.col_join(planar_speeds)
|
1689 |
+
|
1690 |
+
def _orient_frames(self):
|
1691 |
+
self.child_interframe.orient_axis(
|
1692 |
+
self.parent_interframe, self.rotation_axis,
|
1693 |
+
self.rotation_coordinate)
|
1694 |
+
|
1695 |
+
def _set_angular_velocity(self):
|
1696 |
+
self.child_interframe.set_ang_vel(
|
1697 |
+
self.parent_interframe,
|
1698 |
+
self.rotation_speed * self.rotation_axis)
|
1699 |
+
|
1700 |
+
def _set_linear_velocity(self):
|
1701 |
+
self.child_point.set_pos(
|
1702 |
+
self.parent_point,
|
1703 |
+
self.planar_coordinates[0] * self.planar_vectors[0] +
|
1704 |
+
self.planar_coordinates[1] * self.planar_vectors[1])
|
1705 |
+
self.parent_point.set_vel(self.parent_interframe, 0)
|
1706 |
+
self.child_point.set_vel(self.child_interframe, 0)
|
1707 |
+
self.child_point.set_vel(
|
1708 |
+
self.parent.frame, self.planar_speeds[0] * self.planar_vectors[0] +
|
1709 |
+
self.planar_speeds[1] * self.planar_vectors[1])
|
1710 |
+
self.child.masscenter.v2pt_theory(self.child_point, self.parent.frame,
|
1711 |
+
self.child.frame)
|
1712 |
+
|
1713 |
+
|
1714 |
+
class SphericalJoint(Joint):
|
1715 |
+
"""Spherical (Ball-and-Socket) Joint.
|
1716 |
+
|
1717 |
+
.. image:: SphericalJoint.svg
|
1718 |
+
:align: center
|
1719 |
+
:width: 600
|
1720 |
+
|
1721 |
+
Explanation
|
1722 |
+
===========
|
1723 |
+
|
1724 |
+
A spherical joint is defined such that the child body is free to rotate in
|
1725 |
+
any direction, without allowing a translation of the ``child_point``. As can
|
1726 |
+
also be seen in the image, the ``parent_point`` and ``child_point`` are
|
1727 |
+
fixed on top of each other, i.e. the ``joint_point``. This rotation is
|
1728 |
+
defined using the :func:`parent_interframe.orient(child_interframe,
|
1729 |
+
rot_type, amounts, rot_order)
|
1730 |
+
<sympy.physics.vector.frame.ReferenceFrame.orient>` method. The default
|
1731 |
+
rotation consists of three relative rotations, i.e. body-fixed rotations.
|
1732 |
+
Based on the direction cosine matrix following from these rotations, the
|
1733 |
+
angular velocity is computed based on the generalized coordinates and
|
1734 |
+
generalized speeds.
|
1735 |
+
|
1736 |
+
Parameters
|
1737 |
+
==========
|
1738 |
+
|
1739 |
+
name : string
|
1740 |
+
A unique name for the joint.
|
1741 |
+
parent : Body
|
1742 |
+
The parent body of joint.
|
1743 |
+
child : Body
|
1744 |
+
The child body of joint.
|
1745 |
+
coordinates: iterable of dynamicsymbols, optional
|
1746 |
+
Generalized coordinates of the joint.
|
1747 |
+
speeds : iterable of dynamicsymbols, optional
|
1748 |
+
Generalized speeds of joint.
|
1749 |
+
parent_point : Point or Vector, optional
|
1750 |
+
Attachment point where the joint is fixed to the parent body. If a
|
1751 |
+
vector is provided, then the attachment point is computed by adding the
|
1752 |
+
vector to the body's mass center. The default value is the parent's mass
|
1753 |
+
center.
|
1754 |
+
child_point : Point or Vector, optional
|
1755 |
+
Attachment point where the joint is fixed to the child body. If a
|
1756 |
+
vector is provided, then the attachment point is computed by adding the
|
1757 |
+
vector to the body's mass center. The default value is the child's mass
|
1758 |
+
center.
|
1759 |
+
parent_interframe : ReferenceFrame, optional
|
1760 |
+
Intermediate frame of the parent body with respect to which the joint
|
1761 |
+
transformation is formulated. If a Vector is provided then an interframe
|
1762 |
+
is created which aligns its X axis with the given vector. The default
|
1763 |
+
value is the parent's own frame.
|
1764 |
+
child_interframe : ReferenceFrame, optional
|
1765 |
+
Intermediate frame of the child body with respect to which the joint
|
1766 |
+
transformation is formulated. If a Vector is provided then an interframe
|
1767 |
+
is created which aligns its X axis with the given vector. The default
|
1768 |
+
value is the child's own frame.
|
1769 |
+
rot_type : str, optional
|
1770 |
+
The method used to generate the direction cosine matrix. Supported
|
1771 |
+
methods are:
|
1772 |
+
|
1773 |
+
- ``'Body'``: three successive rotations about new intermediate axes,
|
1774 |
+
also called "Euler and Tait-Bryan angles"
|
1775 |
+
- ``'Space'``: three successive rotations about the parent frames' unit
|
1776 |
+
vectors
|
1777 |
+
|
1778 |
+
The default method is ``'Body'``.
|
1779 |
+
amounts :
|
1780 |
+
Expressions defining the rotation angles or direction cosine matrix.
|
1781 |
+
These must match the ``rot_type``. See examples below for details. The
|
1782 |
+
input types are:
|
1783 |
+
|
1784 |
+
- ``'Body'``: 3-tuple of expressions, symbols, or functions
|
1785 |
+
- ``'Space'``: 3-tuple of expressions, symbols, or functions
|
1786 |
+
|
1787 |
+
The default amounts are the given ``coordinates``.
|
1788 |
+
rot_order : str or int, optional
|
1789 |
+
If applicable, the order of the successive of rotations. The string
|
1790 |
+
``'123'`` and integer ``123`` are equivalent, for example. Required for
|
1791 |
+
``'Body'`` and ``'Space'``. The default value is ``123``.
|
1792 |
+
|
1793 |
+
Attributes
|
1794 |
+
==========
|
1795 |
+
|
1796 |
+
name : string
|
1797 |
+
The joint's name.
|
1798 |
+
parent : Body
|
1799 |
+
The joint's parent body.
|
1800 |
+
child : Body
|
1801 |
+
The joint's child body.
|
1802 |
+
coordinates : Matrix
|
1803 |
+
Matrix of the joint's generalized coordinates.
|
1804 |
+
speeds : Matrix
|
1805 |
+
Matrix of the joint's generalized speeds.
|
1806 |
+
parent_point : Point
|
1807 |
+
Attachment point where the joint is fixed to the parent body.
|
1808 |
+
child_point : Point
|
1809 |
+
Attachment point where the joint is fixed to the child body.
|
1810 |
+
parent_interframe : ReferenceFrame
|
1811 |
+
Intermediate frame of the parent body with respect to which the joint
|
1812 |
+
transformation is formulated.
|
1813 |
+
child_interframe : ReferenceFrame
|
1814 |
+
Intermediate frame of the child body with respect to which the joint
|
1815 |
+
transformation is formulated.
|
1816 |
+
kdes : Matrix
|
1817 |
+
Kinematical differential equations of the joint.
|
1818 |
+
|
1819 |
+
Examples
|
1820 |
+
=========
|
1821 |
+
|
1822 |
+
A single spherical joint is created from two bodies and has the following
|
1823 |
+
basic attributes:
|
1824 |
+
|
1825 |
+
>>> from sympy.physics.mechanics import Body, SphericalJoint
|
1826 |
+
>>> parent = Body('P')
|
1827 |
+
>>> parent
|
1828 |
+
P
|
1829 |
+
>>> child = Body('C')
|
1830 |
+
>>> child
|
1831 |
+
C
|
1832 |
+
>>> joint = SphericalJoint('PC', parent, child)
|
1833 |
+
>>> joint
|
1834 |
+
SphericalJoint: PC parent: P child: C
|
1835 |
+
>>> joint.name
|
1836 |
+
'PC'
|
1837 |
+
>>> joint.parent
|
1838 |
+
P
|
1839 |
+
>>> joint.child
|
1840 |
+
C
|
1841 |
+
>>> joint.parent_point
|
1842 |
+
P_masscenter
|
1843 |
+
>>> joint.child_point
|
1844 |
+
C_masscenter
|
1845 |
+
>>> joint.parent_interframe
|
1846 |
+
P_frame
|
1847 |
+
>>> joint.child_interframe
|
1848 |
+
C_frame
|
1849 |
+
>>> joint.coordinates
|
1850 |
+
Matrix([
|
1851 |
+
[q0_PC(t)],
|
1852 |
+
[q1_PC(t)],
|
1853 |
+
[q2_PC(t)]])
|
1854 |
+
>>> joint.speeds
|
1855 |
+
Matrix([
|
1856 |
+
[u0_PC(t)],
|
1857 |
+
[u1_PC(t)],
|
1858 |
+
[u2_PC(t)]])
|
1859 |
+
>>> child.frame.ang_vel_in(parent.frame).to_matrix(child.frame)
|
1860 |
+
Matrix([
|
1861 |
+
[ u0_PC(t)*cos(q1_PC(t))*cos(q2_PC(t)) + u1_PC(t)*sin(q2_PC(t))],
|
1862 |
+
[-u0_PC(t)*sin(q2_PC(t))*cos(q1_PC(t)) + u1_PC(t)*cos(q2_PC(t))],
|
1863 |
+
[ u0_PC(t)*sin(q1_PC(t)) + u2_PC(t)]])
|
1864 |
+
>>> child.frame.x.to_matrix(parent.frame)
|
1865 |
+
Matrix([
|
1866 |
+
[ cos(q1_PC(t))*cos(q2_PC(t))],
|
1867 |
+
[sin(q0_PC(t))*sin(q1_PC(t))*cos(q2_PC(t)) + sin(q2_PC(t))*cos(q0_PC(t))],
|
1868 |
+
[sin(q0_PC(t))*sin(q2_PC(t)) - sin(q1_PC(t))*cos(q0_PC(t))*cos(q2_PC(t))]])
|
1869 |
+
>>> joint.child_point.pos_from(joint.parent_point)
|
1870 |
+
0
|
1871 |
+
|
1872 |
+
To further demonstrate the use of the spherical joint, the kinematics of a
|
1873 |
+
spherical joint with a ZXZ rotation can be created as follows.
|
1874 |
+
|
1875 |
+
>>> from sympy import symbols
|
1876 |
+
>>> from sympy.physics.mechanics import Body, SphericalJoint
|
1877 |
+
>>> l1 = symbols('l1')
|
1878 |
+
|
1879 |
+
First create bodies to represent the fixed floor and a pendulum bob.
|
1880 |
+
|
1881 |
+
>>> floor = Body('F')
|
1882 |
+
>>> bob = Body('B')
|
1883 |
+
|
1884 |
+
The joint will connect the bob to the floor, with the joint located at a
|
1885 |
+
distance of ``l1`` from the child's center of mass and the rotation set to a
|
1886 |
+
body-fixed ZXZ rotation.
|
1887 |
+
|
1888 |
+
>>> joint = SphericalJoint('S', floor, bob, child_point=l1 * bob.y,
|
1889 |
+
... rot_type='body', rot_order='ZXZ')
|
1890 |
+
|
1891 |
+
Now that the joint is established, the kinematics of the connected body can
|
1892 |
+
be accessed.
|
1893 |
+
|
1894 |
+
The position of the bob's masscenter is found with:
|
1895 |
+
|
1896 |
+
>>> bob.masscenter.pos_from(floor.masscenter)
|
1897 |
+
- l1*B_frame.y
|
1898 |
+
|
1899 |
+
The angular velocities of the pendulum link can be computed with respect to
|
1900 |
+
the floor.
|
1901 |
+
|
1902 |
+
>>> bob.frame.ang_vel_in(floor.frame).to_matrix(
|
1903 |
+
... floor.frame).simplify()
|
1904 |
+
Matrix([
|
1905 |
+
[u1_S(t)*cos(q0_S(t)) + u2_S(t)*sin(q0_S(t))*sin(q1_S(t))],
|
1906 |
+
[u1_S(t)*sin(q0_S(t)) - u2_S(t)*sin(q1_S(t))*cos(q0_S(t))],
|
1907 |
+
[ u0_S(t) + u2_S(t)*cos(q1_S(t))]])
|
1908 |
+
|
1909 |
+
Finally, the linear velocity of the bob's center of mass can be computed.
|
1910 |
+
|
1911 |
+
>>> bob.masscenter.vel(floor.frame).to_matrix(bob.frame)
|
1912 |
+
Matrix([
|
1913 |
+
[ l1*(u0_S(t)*cos(q1_S(t)) + u2_S(t))],
|
1914 |
+
[ 0],
|
1915 |
+
[-l1*(u0_S(t)*sin(q1_S(t))*sin(q2_S(t)) + u1_S(t)*cos(q2_S(t)))]])
|
1916 |
+
|
1917 |
+
"""
|
1918 |
+
def __init__(self, name, parent, child, coordinates=None, speeds=None,
|
1919 |
+
parent_point=None, child_point=None, parent_interframe=None,
|
1920 |
+
child_interframe=None, rot_type='BODY', amounts=None,
|
1921 |
+
rot_order=123):
|
1922 |
+
self._rot_type = rot_type
|
1923 |
+
self._amounts = amounts
|
1924 |
+
self._rot_order = rot_order
|
1925 |
+
super().__init__(name, parent, child, coordinates, speeds,
|
1926 |
+
parent_point, child_point,
|
1927 |
+
parent_interframe=parent_interframe,
|
1928 |
+
child_interframe=child_interframe)
|
1929 |
+
|
1930 |
+
def __str__(self):
|
1931 |
+
return (f'SphericalJoint: {self.name} parent: {self.parent} '
|
1932 |
+
f'child: {self.child}')
|
1933 |
+
|
1934 |
+
def _generate_coordinates(self, coordinates):
|
1935 |
+
return self._fill_coordinate_list(coordinates, 3, 'q')
|
1936 |
+
|
1937 |
+
def _generate_speeds(self, speeds):
|
1938 |
+
return self._fill_coordinate_list(speeds, len(self.coordinates), 'u')
|
1939 |
+
|
1940 |
+
def _orient_frames(self):
|
1941 |
+
supported_rot_types = ('BODY', 'SPACE')
|
1942 |
+
if self._rot_type.upper() not in supported_rot_types:
|
1943 |
+
raise NotImplementedError(
|
1944 |
+
f'Rotation type "{self._rot_type}" is not implemented. '
|
1945 |
+
f'Implemented rotation types are: {supported_rot_types}')
|
1946 |
+
amounts = self.coordinates if self._amounts is None else self._amounts
|
1947 |
+
self.child_interframe.orient(self.parent_interframe, self._rot_type,
|
1948 |
+
amounts, self._rot_order)
|
1949 |
+
|
1950 |
+
def _set_angular_velocity(self):
|
1951 |
+
t = dynamicsymbols._t
|
1952 |
+
vel = self.child_interframe.ang_vel_in(self.parent_interframe).xreplace(
|
1953 |
+
{q.diff(t): u for q, u in zip(self.coordinates, self.speeds)}
|
1954 |
+
)
|
1955 |
+
self.child_interframe.set_ang_vel(self.parent_interframe, vel)
|
1956 |
+
|
1957 |
+
def _set_linear_velocity(self):
|
1958 |
+
self.child_point.set_pos(self.parent_point, 0)
|
1959 |
+
self.parent_point.set_vel(self.parent.frame, 0)
|
1960 |
+
self.child_point.set_vel(self.child.frame, 0)
|
1961 |
+
self.child.masscenter.v2pt_theory(self.parent_point, self.parent.frame,
|
1962 |
+
self.child.frame)
|
1963 |
+
|
1964 |
+
|
1965 |
+
class WeldJoint(Joint):
|
1966 |
+
"""Weld Joint.
|
1967 |
+
|
1968 |
+
.. image:: WeldJoint.svg
|
1969 |
+
:align: center
|
1970 |
+
:width: 500
|
1971 |
+
|
1972 |
+
Explanation
|
1973 |
+
===========
|
1974 |
+
|
1975 |
+
A weld joint is defined such that there is no relative motion between the
|
1976 |
+
child and parent bodies. The direction cosine matrix between the attachment
|
1977 |
+
frame (``parent_interframe`` and ``child_interframe``) is the identity
|
1978 |
+
matrix and the attachment points (``parent_point`` and ``child_point``) are
|
1979 |
+
coincident. The page on the joints framework gives a more detailed
|
1980 |
+
explanation of the intermediate frames.
|
1981 |
+
|
1982 |
+
Parameters
|
1983 |
+
==========
|
1984 |
+
|
1985 |
+
name : string
|
1986 |
+
A unique name for the joint.
|
1987 |
+
parent : Body
|
1988 |
+
The parent body of joint.
|
1989 |
+
child : Body
|
1990 |
+
The child body of joint.
|
1991 |
+
parent_point : Point or Vector, optional
|
1992 |
+
Attachment point where the joint is fixed to the parent body. If a
|
1993 |
+
vector is provided, then the attachment point is computed by adding the
|
1994 |
+
vector to the body's mass center. The default value is the parent's mass
|
1995 |
+
center.
|
1996 |
+
child_point : Point or Vector, optional
|
1997 |
+
Attachment point where the joint is fixed to the child body. If a
|
1998 |
+
vector is provided, then the attachment point is computed by adding the
|
1999 |
+
vector to the body's mass center. The default value is the child's mass
|
2000 |
+
center.
|
2001 |
+
parent_interframe : ReferenceFrame, optional
|
2002 |
+
Intermediate frame of the parent body with respect to which the joint
|
2003 |
+
transformation is formulated. If a Vector is provided then an interframe
|
2004 |
+
is created which aligns its X axis with the given vector. The default
|
2005 |
+
value is the parent's own frame.
|
2006 |
+
child_interframe : ReferenceFrame, optional
|
2007 |
+
Intermediate frame of the child body with respect to which the joint
|
2008 |
+
transformation is formulated. If a Vector is provided then an interframe
|
2009 |
+
is created which aligns its X axis with the given vector. The default
|
2010 |
+
value is the child's own frame.
|
2011 |
+
|
2012 |
+
Attributes
|
2013 |
+
==========
|
2014 |
+
|
2015 |
+
name : string
|
2016 |
+
The joint's name.
|
2017 |
+
parent : Body
|
2018 |
+
The joint's parent body.
|
2019 |
+
child : Body
|
2020 |
+
The joint's child body.
|
2021 |
+
coordinates : Matrix
|
2022 |
+
Matrix of the joint's generalized coordinates. The default value is
|
2023 |
+
``dynamicsymbols(f'q_{joint.name}')``.
|
2024 |
+
speeds : Matrix
|
2025 |
+
Matrix of the joint's generalized speeds. The default value is
|
2026 |
+
``dynamicsymbols(f'u_{joint.name}')``.
|
2027 |
+
parent_point : Point
|
2028 |
+
Attachment point where the joint is fixed to the parent body.
|
2029 |
+
child_point : Point
|
2030 |
+
Attachment point where the joint is fixed to the child body.
|
2031 |
+
parent_interframe : ReferenceFrame
|
2032 |
+
Intermediate frame of the parent body with respect to which the joint
|
2033 |
+
transformation is formulated.
|
2034 |
+
child_interframe : ReferenceFrame
|
2035 |
+
Intermediate frame of the child body with respect to which the joint
|
2036 |
+
transformation is formulated.
|
2037 |
+
kdes : Matrix
|
2038 |
+
Kinematical differential equations of the joint.
|
2039 |
+
|
2040 |
+
Examples
|
2041 |
+
=========
|
2042 |
+
|
2043 |
+
A single weld joint is created from two bodies and has the following basic
|
2044 |
+
attributes:
|
2045 |
+
|
2046 |
+
>>> from sympy.physics.mechanics import Body, WeldJoint
|
2047 |
+
>>> parent = Body('P')
|
2048 |
+
>>> parent
|
2049 |
+
P
|
2050 |
+
>>> child = Body('C')
|
2051 |
+
>>> child
|
2052 |
+
C
|
2053 |
+
>>> joint = WeldJoint('PC', parent, child)
|
2054 |
+
>>> joint
|
2055 |
+
WeldJoint: PC parent: P child: C
|
2056 |
+
>>> joint.name
|
2057 |
+
'PC'
|
2058 |
+
>>> joint.parent
|
2059 |
+
P
|
2060 |
+
>>> joint.child
|
2061 |
+
C
|
2062 |
+
>>> joint.parent_point
|
2063 |
+
P_masscenter
|
2064 |
+
>>> joint.child_point
|
2065 |
+
C_masscenter
|
2066 |
+
>>> joint.coordinates
|
2067 |
+
Matrix(0, 0, [])
|
2068 |
+
>>> joint.speeds
|
2069 |
+
Matrix(0, 0, [])
|
2070 |
+
>>> joint.child.frame.ang_vel_in(joint.parent.frame)
|
2071 |
+
0
|
2072 |
+
>>> joint.child.frame.dcm(joint.parent.frame)
|
2073 |
+
Matrix([
|
2074 |
+
[1, 0, 0],
|
2075 |
+
[0, 1, 0],
|
2076 |
+
[0, 0, 1]])
|
2077 |
+
>>> joint.child_point.pos_from(joint.parent_point)
|
2078 |
+
0
|
2079 |
+
|
2080 |
+
To further demonstrate the use of the weld joint, two relatively-fixed
|
2081 |
+
bodies rotated by a quarter turn about the Y axis can be created as follows:
|
2082 |
+
|
2083 |
+
>>> from sympy import symbols, pi
|
2084 |
+
>>> from sympy.physics.mechanics import ReferenceFrame, Body, WeldJoint
|
2085 |
+
>>> l1, l2 = symbols('l1 l2')
|
2086 |
+
|
2087 |
+
First create the bodies to represent the parent and rotated child body.
|
2088 |
+
|
2089 |
+
>>> parent = Body('P')
|
2090 |
+
>>> child = Body('C')
|
2091 |
+
|
2092 |
+
Next the intermediate frame specifying the fixed rotation with respect to
|
2093 |
+
the parent can be created.
|
2094 |
+
|
2095 |
+
>>> rotated_frame = ReferenceFrame('Pr')
|
2096 |
+
>>> rotated_frame.orient_axis(parent.frame, parent.y, pi / 2)
|
2097 |
+
|
2098 |
+
The weld between the parent body and child body is located at a distance
|
2099 |
+
``l1`` from the parent's center of mass in the X direction and ``l2`` from
|
2100 |
+
the child's center of mass in the child's negative X direction.
|
2101 |
+
|
2102 |
+
>>> weld = WeldJoint('weld', parent, child, parent_point=l1 * parent.x,
|
2103 |
+
... child_point=-l2 * child.x,
|
2104 |
+
... parent_interframe=rotated_frame)
|
2105 |
+
|
2106 |
+
Now that the joint has been established, the kinematics of the bodies can be
|
2107 |
+
accessed. The direction cosine matrix of the child body with respect to the
|
2108 |
+
parent can be found:
|
2109 |
+
|
2110 |
+
>>> child.dcm(parent)
|
2111 |
+
Matrix([
|
2112 |
+
[0, 0, -1],
|
2113 |
+
[0, 1, 0],
|
2114 |
+
[1, 0, 0]])
|
2115 |
+
|
2116 |
+
As can also been seen from the direction cosine matrix, the parent X axis is
|
2117 |
+
aligned with the child's Z axis:
|
2118 |
+
>>> parent.x == child.z
|
2119 |
+
True
|
2120 |
+
|
2121 |
+
The position of the child's center of mass with respect to the parent's
|
2122 |
+
center of mass can be found with:
|
2123 |
+
|
2124 |
+
>>> child.masscenter.pos_from(parent.masscenter)
|
2125 |
+
l1*P_frame.x + l2*C_frame.x
|
2126 |
+
|
2127 |
+
The angular velocity of the child with respect to the parent is 0 as one
|
2128 |
+
would expect.
|
2129 |
+
|
2130 |
+
>>> child.ang_vel_in(parent)
|
2131 |
+
0
|
2132 |
+
|
2133 |
+
"""
|
2134 |
+
|
2135 |
+
def __init__(self, name, parent, child, parent_point=None, child_point=None,
|
2136 |
+
parent_interframe=None, child_interframe=None):
|
2137 |
+
super().__init__(name, parent, child, [], [], parent_point,
|
2138 |
+
child_point, parent_interframe=parent_interframe,
|
2139 |
+
child_interframe=child_interframe)
|
2140 |
+
self._kdes = Matrix(1, 0, []).T # Removes stackability problems #10770
|
2141 |
+
|
2142 |
+
def __str__(self):
|
2143 |
+
return (f'WeldJoint: {self.name} parent: {self.parent} '
|
2144 |
+
f'child: {self.child}')
|
2145 |
+
|
2146 |
+
def _generate_coordinates(self, coordinate):
|
2147 |
+
return Matrix()
|
2148 |
+
|
2149 |
+
def _generate_speeds(self, speed):
|
2150 |
+
return Matrix()
|
2151 |
+
|
2152 |
+
def _orient_frames(self):
|
2153 |
+
self.child_interframe.orient_axis(self.parent_interframe,
|
2154 |
+
self.parent_interframe.x, 0)
|
2155 |
+
|
2156 |
+
def _set_angular_velocity(self):
|
2157 |
+
self.child_interframe.set_ang_vel(self.parent_interframe, 0)
|
2158 |
+
|
2159 |
+
def _set_linear_velocity(self):
|
2160 |
+
self.child_point.set_pos(self.parent_point, 0)
|
2161 |
+
self.parent_point.set_vel(self.parent.frame, 0)
|
2162 |
+
self.child_point.set_vel(self.child.frame, 0)
|
2163 |
+
self.child.masscenter.set_vel(self.parent.frame, 0)
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/jointsmethod.py
ADDED
@@ -0,0 +1,279 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.physics.mechanics import (Body, Lagrangian, KanesMethod, LagrangesMethod,
|
2 |
+
RigidBody, Particle)
|
3 |
+
from sympy.physics.mechanics.method import _Methods
|
4 |
+
from sympy.core.backend import Matrix
|
5 |
+
|
6 |
+
__all__ = ['JointsMethod']
|
7 |
+
|
8 |
+
|
9 |
+
class JointsMethod(_Methods):
|
10 |
+
"""Method for formulating the equations of motion using a set of interconnected bodies with joints.
|
11 |
+
|
12 |
+
Parameters
|
13 |
+
==========
|
14 |
+
|
15 |
+
newtonion : Body or ReferenceFrame
|
16 |
+
The newtonion(inertial) frame.
|
17 |
+
*joints : Joint
|
18 |
+
The joints in the system
|
19 |
+
|
20 |
+
Attributes
|
21 |
+
==========
|
22 |
+
|
23 |
+
q, u : iterable
|
24 |
+
Iterable of the generalized coordinates and speeds
|
25 |
+
bodies : iterable
|
26 |
+
Iterable of Body objects in the system.
|
27 |
+
loads : iterable
|
28 |
+
Iterable of (Point, vector) or (ReferenceFrame, vector) tuples
|
29 |
+
describing the forces on the system.
|
30 |
+
mass_matrix : Matrix, shape(n, n)
|
31 |
+
The system's mass matrix
|
32 |
+
forcing : Matrix, shape(n, 1)
|
33 |
+
The system's forcing vector
|
34 |
+
mass_matrix_full : Matrix, shape(2*n, 2*n)
|
35 |
+
The "mass matrix" for the u's and q's
|
36 |
+
forcing_full : Matrix, shape(2*n, 1)
|
37 |
+
The "forcing vector" for the u's and q's
|
38 |
+
method : KanesMethod or Lagrange's method
|
39 |
+
Method's object.
|
40 |
+
kdes : iterable
|
41 |
+
Iterable of kde in they system.
|
42 |
+
|
43 |
+
Examples
|
44 |
+
========
|
45 |
+
|
46 |
+
This is a simple example for a one degree of freedom translational
|
47 |
+
spring-mass-damper.
|
48 |
+
|
49 |
+
>>> from sympy import symbols
|
50 |
+
>>> from sympy.physics.mechanics import Body, JointsMethod, PrismaticJoint
|
51 |
+
>>> from sympy.physics.vector import dynamicsymbols
|
52 |
+
>>> c, k = symbols('c k')
|
53 |
+
>>> x, v = dynamicsymbols('x v')
|
54 |
+
>>> wall = Body('W')
|
55 |
+
>>> body = Body('B')
|
56 |
+
>>> J = PrismaticJoint('J', wall, body, coordinates=x, speeds=v)
|
57 |
+
>>> wall.apply_force(c*v*wall.x, reaction_body=body)
|
58 |
+
>>> wall.apply_force(k*x*wall.x, reaction_body=body)
|
59 |
+
>>> method = JointsMethod(wall, J)
|
60 |
+
>>> method.form_eoms()
|
61 |
+
Matrix([[-B_mass*Derivative(v(t), t) - c*v(t) - k*x(t)]])
|
62 |
+
>>> M = method.mass_matrix_full
|
63 |
+
>>> F = method.forcing_full
|
64 |
+
>>> rhs = M.LUsolve(F)
|
65 |
+
>>> rhs
|
66 |
+
Matrix([
|
67 |
+
[ v(t)],
|
68 |
+
[(-c*v(t) - k*x(t))/B_mass]])
|
69 |
+
|
70 |
+
Notes
|
71 |
+
=====
|
72 |
+
|
73 |
+
``JointsMethod`` currently only works with systems that do not have any
|
74 |
+
configuration or motion constraints.
|
75 |
+
|
76 |
+
"""
|
77 |
+
|
78 |
+
def __init__(self, newtonion, *joints):
|
79 |
+
if isinstance(newtonion, Body):
|
80 |
+
self.frame = newtonion.frame
|
81 |
+
else:
|
82 |
+
self.frame = newtonion
|
83 |
+
|
84 |
+
self._joints = joints
|
85 |
+
self._bodies = self._generate_bodylist()
|
86 |
+
self._loads = self._generate_loadlist()
|
87 |
+
self._q = self._generate_q()
|
88 |
+
self._u = self._generate_u()
|
89 |
+
self._kdes = self._generate_kdes()
|
90 |
+
|
91 |
+
self._method = None
|
92 |
+
|
93 |
+
@property
|
94 |
+
def bodies(self):
|
95 |
+
"""List of bodies in they system."""
|
96 |
+
return self._bodies
|
97 |
+
|
98 |
+
@property
|
99 |
+
def loads(self):
|
100 |
+
"""List of loads on the system."""
|
101 |
+
return self._loads
|
102 |
+
|
103 |
+
@property
|
104 |
+
def q(self):
|
105 |
+
"""List of the generalized coordinates."""
|
106 |
+
return self._q
|
107 |
+
|
108 |
+
@property
|
109 |
+
def u(self):
|
110 |
+
"""List of the generalized speeds."""
|
111 |
+
return self._u
|
112 |
+
|
113 |
+
@property
|
114 |
+
def kdes(self):
|
115 |
+
"""List of the generalized coordinates."""
|
116 |
+
return self._kdes
|
117 |
+
|
118 |
+
@property
|
119 |
+
def forcing_full(self):
|
120 |
+
"""The "forcing vector" for the u's and q's."""
|
121 |
+
return self.method.forcing_full
|
122 |
+
|
123 |
+
@property
|
124 |
+
def mass_matrix_full(self):
|
125 |
+
"""The "mass matrix" for the u's and q's."""
|
126 |
+
return self.method.mass_matrix_full
|
127 |
+
|
128 |
+
@property
|
129 |
+
def mass_matrix(self):
|
130 |
+
"""The system's mass matrix."""
|
131 |
+
return self.method.mass_matrix
|
132 |
+
|
133 |
+
@property
|
134 |
+
def forcing(self):
|
135 |
+
"""The system's forcing vector."""
|
136 |
+
return self.method.forcing
|
137 |
+
|
138 |
+
@property
|
139 |
+
def method(self):
|
140 |
+
"""Object of method used to form equations of systems."""
|
141 |
+
return self._method
|
142 |
+
|
143 |
+
def _generate_bodylist(self):
|
144 |
+
bodies = []
|
145 |
+
for joint in self._joints:
|
146 |
+
if joint.child not in bodies:
|
147 |
+
bodies.append(joint.child)
|
148 |
+
if joint.parent not in bodies:
|
149 |
+
bodies.append(joint.parent)
|
150 |
+
return bodies
|
151 |
+
|
152 |
+
def _generate_loadlist(self):
|
153 |
+
load_list = []
|
154 |
+
for body in self.bodies:
|
155 |
+
load_list.extend(body.loads)
|
156 |
+
return load_list
|
157 |
+
|
158 |
+
def _generate_q(self):
|
159 |
+
q_ind = []
|
160 |
+
for joint in self._joints:
|
161 |
+
for coordinate in joint.coordinates:
|
162 |
+
if coordinate in q_ind:
|
163 |
+
raise ValueError('Coordinates of joints should be unique.')
|
164 |
+
q_ind.append(coordinate)
|
165 |
+
return Matrix(q_ind)
|
166 |
+
|
167 |
+
def _generate_u(self):
|
168 |
+
u_ind = []
|
169 |
+
for joint in self._joints:
|
170 |
+
for speed in joint.speeds:
|
171 |
+
if speed in u_ind:
|
172 |
+
raise ValueError('Speeds of joints should be unique.')
|
173 |
+
u_ind.append(speed)
|
174 |
+
return Matrix(u_ind)
|
175 |
+
|
176 |
+
def _generate_kdes(self):
|
177 |
+
kd_ind = Matrix(1, 0, []).T
|
178 |
+
for joint in self._joints:
|
179 |
+
kd_ind = kd_ind.col_join(joint.kdes)
|
180 |
+
return kd_ind
|
181 |
+
|
182 |
+
def _convert_bodies(self):
|
183 |
+
# Convert `Body` to `Particle` and `RigidBody`
|
184 |
+
bodylist = []
|
185 |
+
for body in self.bodies:
|
186 |
+
if body.is_rigidbody:
|
187 |
+
rb = RigidBody(body.name, body.masscenter, body.frame, body.mass,
|
188 |
+
(body.central_inertia, body.masscenter))
|
189 |
+
rb.potential_energy = body.potential_energy
|
190 |
+
bodylist.append(rb)
|
191 |
+
else:
|
192 |
+
part = Particle(body.name, body.masscenter, body.mass)
|
193 |
+
part.potential_energy = body.potential_energy
|
194 |
+
bodylist.append(part)
|
195 |
+
return bodylist
|
196 |
+
|
197 |
+
def form_eoms(self, method=KanesMethod):
|
198 |
+
"""Method to form system's equation of motions.
|
199 |
+
|
200 |
+
Parameters
|
201 |
+
==========
|
202 |
+
|
203 |
+
method : Class
|
204 |
+
Class name of method.
|
205 |
+
|
206 |
+
Returns
|
207 |
+
========
|
208 |
+
|
209 |
+
Matrix
|
210 |
+
Vector of equations of motions.
|
211 |
+
|
212 |
+
Examples
|
213 |
+
========
|
214 |
+
|
215 |
+
This is a simple example for a one degree of freedom translational
|
216 |
+
spring-mass-damper.
|
217 |
+
|
218 |
+
>>> from sympy import S, symbols
|
219 |
+
>>> from sympy.physics.mechanics import LagrangesMethod, dynamicsymbols, Body
|
220 |
+
>>> from sympy.physics.mechanics import PrismaticJoint, JointsMethod
|
221 |
+
>>> q = dynamicsymbols('q')
|
222 |
+
>>> qd = dynamicsymbols('q', 1)
|
223 |
+
>>> m, k, b = symbols('m k b')
|
224 |
+
>>> wall = Body('W')
|
225 |
+
>>> part = Body('P', mass=m)
|
226 |
+
>>> part.potential_energy = k * q**2 / S(2)
|
227 |
+
>>> J = PrismaticJoint('J', wall, part, coordinates=q, speeds=qd)
|
228 |
+
>>> wall.apply_force(b * qd * wall.x, reaction_body=part)
|
229 |
+
>>> method = JointsMethod(wall, J)
|
230 |
+
>>> method.form_eoms(LagrangesMethod)
|
231 |
+
Matrix([[b*Derivative(q(t), t) + k*q(t) + m*Derivative(q(t), (t, 2))]])
|
232 |
+
|
233 |
+
We can also solve for the states using the 'rhs' method.
|
234 |
+
|
235 |
+
>>> method.rhs()
|
236 |
+
Matrix([
|
237 |
+
[ Derivative(q(t), t)],
|
238 |
+
[(-b*Derivative(q(t), t) - k*q(t))/m]])
|
239 |
+
|
240 |
+
"""
|
241 |
+
|
242 |
+
bodylist = self._convert_bodies()
|
243 |
+
if issubclass(method, LagrangesMethod): #LagrangesMethod or similar
|
244 |
+
L = Lagrangian(self.frame, *bodylist)
|
245 |
+
self._method = method(L, self.q, self.loads, bodylist, self.frame)
|
246 |
+
else: #KanesMethod or similar
|
247 |
+
self._method = method(self.frame, q_ind=self.q, u_ind=self.u, kd_eqs=self.kdes,
|
248 |
+
forcelist=self.loads, bodies=bodylist)
|
249 |
+
soln = self.method._form_eoms()
|
250 |
+
return soln
|
251 |
+
|
252 |
+
def rhs(self, inv_method=None):
|
253 |
+
"""Returns equations that can be solved numerically.
|
254 |
+
|
255 |
+
Parameters
|
256 |
+
==========
|
257 |
+
|
258 |
+
inv_method : str
|
259 |
+
The specific sympy inverse matrix calculation method to use. For a
|
260 |
+
list of valid methods, see
|
261 |
+
:meth:`~sympy.matrices.matrices.MatrixBase.inv`
|
262 |
+
|
263 |
+
Returns
|
264 |
+
========
|
265 |
+
|
266 |
+
Matrix
|
267 |
+
Numerically solvable equations.
|
268 |
+
|
269 |
+
See Also
|
270 |
+
========
|
271 |
+
|
272 |
+
sympy.physics.mechanics.kane.KanesMethod.rhs:
|
273 |
+
KanesMethod's rhs function.
|
274 |
+
sympy.physics.mechanics.lagrange.LagrangesMethod.rhs:
|
275 |
+
LagrangesMethod's rhs function.
|
276 |
+
|
277 |
+
"""
|
278 |
+
|
279 |
+
return self.method.rhs(inv_method=inv_method)
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/kane.py
ADDED
@@ -0,0 +1,741 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.core.backend import zeros, Matrix, diff, eye
|
2 |
+
from sympy.core.sorting import default_sort_key
|
3 |
+
from sympy.physics.vector import (ReferenceFrame, dynamicsymbols,
|
4 |
+
partial_velocity)
|
5 |
+
from sympy.physics.mechanics.method import _Methods
|
6 |
+
from sympy.physics.mechanics.particle import Particle
|
7 |
+
from sympy.physics.mechanics.rigidbody import RigidBody
|
8 |
+
from sympy.physics.mechanics.functions import (
|
9 |
+
msubs, find_dynamicsymbols, _f_list_parser, _validate_coordinates)
|
10 |
+
from sympy.physics.mechanics.linearize import Linearizer
|
11 |
+
from sympy.utilities.iterables import iterable
|
12 |
+
|
13 |
+
__all__ = ['KanesMethod']
|
14 |
+
|
15 |
+
|
16 |
+
class KanesMethod(_Methods):
|
17 |
+
r"""Kane's method object.
|
18 |
+
|
19 |
+
Explanation
|
20 |
+
===========
|
21 |
+
|
22 |
+
This object is used to do the "book-keeping" as you go through and form
|
23 |
+
equations of motion in the way Kane presents in:
|
24 |
+
Kane, T., Levinson, D. Dynamics Theory and Applications. 1985 McGraw-Hill
|
25 |
+
|
26 |
+
The attributes are for equations in the form [M] udot = forcing.
|
27 |
+
|
28 |
+
Attributes
|
29 |
+
==========
|
30 |
+
|
31 |
+
q, u : Matrix
|
32 |
+
Matrices of the generalized coordinates and speeds
|
33 |
+
bodies : iterable
|
34 |
+
Iterable of Point and RigidBody objects in the system.
|
35 |
+
loads : iterable
|
36 |
+
Iterable of (Point, vector) or (ReferenceFrame, vector) tuples
|
37 |
+
describing the forces on the system.
|
38 |
+
auxiliary_eqs : Matrix
|
39 |
+
If applicable, the set of auxiliary Kane's
|
40 |
+
equations used to solve for non-contributing
|
41 |
+
forces.
|
42 |
+
mass_matrix : Matrix
|
43 |
+
The system's dynamics mass matrix: [k_d; k_dnh]
|
44 |
+
forcing : Matrix
|
45 |
+
The system's dynamics forcing vector: -[f_d; f_dnh]
|
46 |
+
mass_matrix_kin : Matrix
|
47 |
+
The "mass matrix" for kinematic differential equations: k_kqdot
|
48 |
+
forcing_kin : Matrix
|
49 |
+
The forcing vector for kinematic differential equations: -(k_ku*u + f_k)
|
50 |
+
mass_matrix_full : Matrix
|
51 |
+
The "mass matrix" for the u's and q's with dynamics and kinematics
|
52 |
+
forcing_full : Matrix
|
53 |
+
The "forcing vector" for the u's and q's with dynamics and kinematics
|
54 |
+
explicit_kinematics : bool
|
55 |
+
Boolean whether the mass matrices and forcing vectors should use the
|
56 |
+
explicit form (default) or implicit form for kinematics.
|
57 |
+
See the notes for more details.
|
58 |
+
|
59 |
+
Notes
|
60 |
+
=====
|
61 |
+
|
62 |
+
The mass matrices and forcing vectors related to kinematic equations
|
63 |
+
are given in the explicit form by default. In other words, the kinematic
|
64 |
+
mass matrix is $\mathbf{k_{k\dot{q}}} = \mathbf{I}$.
|
65 |
+
In order to get the implicit form of those matrices/vectors, you can set the
|
66 |
+
``explicit_kinematics`` attribute to ``False``. So $\mathbf{k_{k\dot{q}}}$ is not
|
67 |
+
necessarily an identity matrix. This can provide more compact equations for
|
68 |
+
non-simple kinematics (see #22626).
|
69 |
+
|
70 |
+
Examples
|
71 |
+
========
|
72 |
+
|
73 |
+
This is a simple example for a one degree of freedom translational
|
74 |
+
spring-mass-damper.
|
75 |
+
|
76 |
+
In this example, we first need to do the kinematics.
|
77 |
+
This involves creating generalized speeds and coordinates and their
|
78 |
+
derivatives.
|
79 |
+
Then we create a point and set its velocity in a frame.
|
80 |
+
|
81 |
+
>>> from sympy import symbols
|
82 |
+
>>> from sympy.physics.mechanics import dynamicsymbols, ReferenceFrame
|
83 |
+
>>> from sympy.physics.mechanics import Point, Particle, KanesMethod
|
84 |
+
>>> q, u = dynamicsymbols('q u')
|
85 |
+
>>> qd, ud = dynamicsymbols('q u', 1)
|
86 |
+
>>> m, c, k = symbols('m c k')
|
87 |
+
>>> N = ReferenceFrame('N')
|
88 |
+
>>> P = Point('P')
|
89 |
+
>>> P.set_vel(N, u * N.x)
|
90 |
+
|
91 |
+
Next we need to arrange/store information in the way that KanesMethod
|
92 |
+
requires. The kinematic differential equations need to be stored in a
|
93 |
+
dict. A list of forces/torques must be constructed, where each entry in
|
94 |
+
the list is a (Point, Vector) or (ReferenceFrame, Vector) tuple, where the
|
95 |
+
Vectors represent the Force or Torque.
|
96 |
+
Next a particle needs to be created, and it needs to have a point and mass
|
97 |
+
assigned to it.
|
98 |
+
Finally, a list of all bodies and particles needs to be created.
|
99 |
+
|
100 |
+
>>> kd = [qd - u]
|
101 |
+
>>> FL = [(P, (-k * q - c * u) * N.x)]
|
102 |
+
>>> pa = Particle('pa', P, m)
|
103 |
+
>>> BL = [pa]
|
104 |
+
|
105 |
+
Finally we can generate the equations of motion.
|
106 |
+
First we create the KanesMethod object and supply an inertial frame,
|
107 |
+
coordinates, generalized speeds, and the kinematic differential equations.
|
108 |
+
Additional quantities such as configuration and motion constraints,
|
109 |
+
dependent coordinates and speeds, and auxiliary speeds are also supplied
|
110 |
+
here (see the online documentation).
|
111 |
+
Next we form FR* and FR to complete: Fr + Fr* = 0.
|
112 |
+
We have the equations of motion at this point.
|
113 |
+
It makes sense to rearrange them though, so we calculate the mass matrix and
|
114 |
+
the forcing terms, for E.o.M. in the form: [MM] udot = forcing, where MM is
|
115 |
+
the mass matrix, udot is a vector of the time derivatives of the
|
116 |
+
generalized speeds, and forcing is a vector representing "forcing" terms.
|
117 |
+
|
118 |
+
>>> KM = KanesMethod(N, q_ind=[q], u_ind=[u], kd_eqs=kd)
|
119 |
+
>>> (fr, frstar) = KM.kanes_equations(BL, FL)
|
120 |
+
>>> MM = KM.mass_matrix
|
121 |
+
>>> forcing = KM.forcing
|
122 |
+
>>> rhs = MM.inv() * forcing
|
123 |
+
>>> rhs
|
124 |
+
Matrix([[(-c*u(t) - k*q(t))/m]])
|
125 |
+
>>> KM.linearize(A_and_B=True)[0]
|
126 |
+
Matrix([
|
127 |
+
[ 0, 1],
|
128 |
+
[-k/m, -c/m]])
|
129 |
+
|
130 |
+
Please look at the documentation pages for more information on how to
|
131 |
+
perform linearization and how to deal with dependent coordinates & speeds,
|
132 |
+
and how do deal with bringing non-contributing forces into evidence.
|
133 |
+
|
134 |
+
"""
|
135 |
+
|
136 |
+
def __init__(self, frame, q_ind, u_ind, kd_eqs=None, q_dependent=None,
|
137 |
+
configuration_constraints=None, u_dependent=None,
|
138 |
+
velocity_constraints=None, acceleration_constraints=None,
|
139 |
+
u_auxiliary=None, bodies=None, forcelist=None, explicit_kinematics=True):
|
140 |
+
|
141 |
+
"""Please read the online documentation. """
|
142 |
+
if not q_ind:
|
143 |
+
q_ind = [dynamicsymbols('dummy_q')]
|
144 |
+
kd_eqs = [dynamicsymbols('dummy_kd')]
|
145 |
+
|
146 |
+
if not isinstance(frame, ReferenceFrame):
|
147 |
+
raise TypeError('An inertial ReferenceFrame must be supplied')
|
148 |
+
self._inertial = frame
|
149 |
+
|
150 |
+
self._fr = None
|
151 |
+
self._frstar = None
|
152 |
+
|
153 |
+
self._forcelist = forcelist
|
154 |
+
self._bodylist = bodies
|
155 |
+
|
156 |
+
self.explicit_kinematics = explicit_kinematics
|
157 |
+
|
158 |
+
self._initialize_vectors(q_ind, q_dependent, u_ind, u_dependent,
|
159 |
+
u_auxiliary)
|
160 |
+
_validate_coordinates(self.q, self.u)
|
161 |
+
self._initialize_kindiffeq_matrices(kd_eqs)
|
162 |
+
self._initialize_constraint_matrices(configuration_constraints,
|
163 |
+
velocity_constraints, acceleration_constraints)
|
164 |
+
|
165 |
+
def _initialize_vectors(self, q_ind, q_dep, u_ind, u_dep, u_aux):
|
166 |
+
"""Initialize the coordinate and speed vectors."""
|
167 |
+
|
168 |
+
none_handler = lambda x: Matrix(x) if x else Matrix()
|
169 |
+
|
170 |
+
# Initialize generalized coordinates
|
171 |
+
q_dep = none_handler(q_dep)
|
172 |
+
if not iterable(q_ind):
|
173 |
+
raise TypeError('Generalized coordinates must be an iterable.')
|
174 |
+
if not iterable(q_dep):
|
175 |
+
raise TypeError('Dependent coordinates must be an iterable.')
|
176 |
+
q_ind = Matrix(q_ind)
|
177 |
+
self._qdep = q_dep
|
178 |
+
self._q = Matrix([q_ind, q_dep])
|
179 |
+
self._qdot = self.q.diff(dynamicsymbols._t)
|
180 |
+
|
181 |
+
# Initialize generalized speeds
|
182 |
+
u_dep = none_handler(u_dep)
|
183 |
+
if not iterable(u_ind):
|
184 |
+
raise TypeError('Generalized speeds must be an iterable.')
|
185 |
+
if not iterable(u_dep):
|
186 |
+
raise TypeError('Dependent speeds must be an iterable.')
|
187 |
+
u_ind = Matrix(u_ind)
|
188 |
+
self._udep = u_dep
|
189 |
+
self._u = Matrix([u_ind, u_dep])
|
190 |
+
self._udot = self.u.diff(dynamicsymbols._t)
|
191 |
+
self._uaux = none_handler(u_aux)
|
192 |
+
|
193 |
+
def _initialize_constraint_matrices(self, config, vel, acc):
|
194 |
+
"""Initializes constraint matrices."""
|
195 |
+
|
196 |
+
# Define vector dimensions
|
197 |
+
o = len(self.u)
|
198 |
+
m = len(self._udep)
|
199 |
+
p = o - m
|
200 |
+
none_handler = lambda x: Matrix(x) if x else Matrix()
|
201 |
+
|
202 |
+
# Initialize configuration constraints
|
203 |
+
config = none_handler(config)
|
204 |
+
if len(self._qdep) != len(config):
|
205 |
+
raise ValueError('There must be an equal number of dependent '
|
206 |
+
'coordinates and configuration constraints.')
|
207 |
+
self._f_h = none_handler(config)
|
208 |
+
|
209 |
+
# Initialize velocity and acceleration constraints
|
210 |
+
vel = none_handler(vel)
|
211 |
+
acc = none_handler(acc)
|
212 |
+
if len(vel) != m:
|
213 |
+
raise ValueError('There must be an equal number of dependent '
|
214 |
+
'speeds and velocity constraints.')
|
215 |
+
if acc and (len(acc) != m):
|
216 |
+
raise ValueError('There must be an equal number of dependent '
|
217 |
+
'speeds and acceleration constraints.')
|
218 |
+
if vel:
|
219 |
+
u_zero = {i: 0 for i in self.u}
|
220 |
+
udot_zero = {i: 0 for i in self._udot}
|
221 |
+
|
222 |
+
# When calling kanes_equations, another class instance will be
|
223 |
+
# created if auxiliary u's are present. In this case, the
|
224 |
+
# computation of kinetic differential equation matrices will be
|
225 |
+
# skipped as this was computed during the original KanesMethod
|
226 |
+
# object, and the qd_u_map will not be available.
|
227 |
+
if self._qdot_u_map is not None:
|
228 |
+
vel = msubs(vel, self._qdot_u_map)
|
229 |
+
|
230 |
+
self._f_nh = msubs(vel, u_zero)
|
231 |
+
self._k_nh = (vel - self._f_nh).jacobian(self.u)
|
232 |
+
# If no acceleration constraints given, calculate them.
|
233 |
+
if not acc:
|
234 |
+
_f_dnh = (self._k_nh.diff(dynamicsymbols._t) * self.u +
|
235 |
+
self._f_nh.diff(dynamicsymbols._t))
|
236 |
+
if self._qdot_u_map is not None:
|
237 |
+
_f_dnh = msubs(_f_dnh, self._qdot_u_map)
|
238 |
+
self._f_dnh = _f_dnh
|
239 |
+
self._k_dnh = self._k_nh
|
240 |
+
else:
|
241 |
+
if self._qdot_u_map is not None:
|
242 |
+
acc = msubs(acc, self._qdot_u_map)
|
243 |
+
self._f_dnh = msubs(acc, udot_zero)
|
244 |
+
self._k_dnh = (acc - self._f_dnh).jacobian(self._udot)
|
245 |
+
|
246 |
+
# Form of non-holonomic constraints is B*u + C = 0.
|
247 |
+
# We partition B into independent and dependent columns:
|
248 |
+
# Ars is then -B_dep.inv() * B_ind, and it relates dependent speeds
|
249 |
+
# to independent speeds as: udep = Ars*uind, neglecting the C term.
|
250 |
+
B_ind = self._k_nh[:, :p]
|
251 |
+
B_dep = self._k_nh[:, p:o]
|
252 |
+
self._Ars = -B_dep.LUsolve(B_ind)
|
253 |
+
else:
|
254 |
+
self._f_nh = Matrix()
|
255 |
+
self._k_nh = Matrix()
|
256 |
+
self._f_dnh = Matrix()
|
257 |
+
self._k_dnh = Matrix()
|
258 |
+
self._Ars = Matrix()
|
259 |
+
|
260 |
+
def _initialize_kindiffeq_matrices(self, kdeqs):
|
261 |
+
"""Initialize the kinematic differential equation matrices.
|
262 |
+
|
263 |
+
Parameters
|
264 |
+
==========
|
265 |
+
kdeqs : sequence of sympy expressions
|
266 |
+
Kinematic differential equations in the form of f(u,q',q,t) where
|
267 |
+
f() = 0. The equations have to be linear in the generalized
|
268 |
+
coordinates and generalized speeds.
|
269 |
+
|
270 |
+
"""
|
271 |
+
|
272 |
+
if kdeqs:
|
273 |
+
if len(self.q) != len(kdeqs):
|
274 |
+
raise ValueError('There must be an equal number of kinematic '
|
275 |
+
'differential equations and coordinates.')
|
276 |
+
|
277 |
+
u = self.u
|
278 |
+
qdot = self._qdot
|
279 |
+
|
280 |
+
kdeqs = Matrix(kdeqs)
|
281 |
+
|
282 |
+
u_zero = {ui: 0 for ui in u}
|
283 |
+
uaux_zero = {uai: 0 for uai in self._uaux}
|
284 |
+
qdot_zero = {qdi: 0 for qdi in qdot}
|
285 |
+
|
286 |
+
# Extract the linear coefficient matrices as per the following
|
287 |
+
# equation:
|
288 |
+
#
|
289 |
+
# k_ku(q,t)*u(t) + k_kqdot(q,t)*q'(t) + f_k(q,t) = 0
|
290 |
+
#
|
291 |
+
k_ku = kdeqs.jacobian(u)
|
292 |
+
k_kqdot = kdeqs.jacobian(qdot)
|
293 |
+
f_k = kdeqs.xreplace(u_zero).xreplace(qdot_zero)
|
294 |
+
|
295 |
+
# The kinematic differential equations should be linear in both q'
|
296 |
+
# and u, so check for u and q' in the components.
|
297 |
+
dy_syms = find_dynamicsymbols(k_ku.row_join(k_kqdot).row_join(f_k))
|
298 |
+
nonlin_vars = [vari for vari in u[:] + qdot[:] if vari in dy_syms]
|
299 |
+
if nonlin_vars:
|
300 |
+
msg = ('The provided kinematic differential equations are '
|
301 |
+
'nonlinear in {}. They must be linear in the '
|
302 |
+
'generalized speeds and derivatives of the generalized '
|
303 |
+
'coordinates.')
|
304 |
+
raise ValueError(msg.format(nonlin_vars))
|
305 |
+
|
306 |
+
self._f_k_implicit = f_k.xreplace(uaux_zero)
|
307 |
+
self._k_ku_implicit = k_ku.xreplace(uaux_zero)
|
308 |
+
self._k_kqdot_implicit = k_kqdot
|
309 |
+
|
310 |
+
# Solve for q'(t) such that the coefficient matrices are now in
|
311 |
+
# this form:
|
312 |
+
#
|
313 |
+
# k_kqdot^-1*k_ku*u(t) + I*q'(t) + k_kqdot^-1*f_k = 0
|
314 |
+
#
|
315 |
+
# NOTE : Solving the kinematic differential equations here is not
|
316 |
+
# necessary and prevents the equations from being provided in fully
|
317 |
+
# implicit form.
|
318 |
+
f_k_explicit = k_kqdot.LUsolve(f_k)
|
319 |
+
k_ku_explicit = k_kqdot.LUsolve(k_ku)
|
320 |
+
self._qdot_u_map = dict(zip(qdot, -(k_ku_explicit*u + f_k_explicit)))
|
321 |
+
|
322 |
+
self._f_k = f_k_explicit.xreplace(uaux_zero)
|
323 |
+
self._k_ku = k_ku_explicit.xreplace(uaux_zero)
|
324 |
+
self._k_kqdot = eye(len(qdot))
|
325 |
+
|
326 |
+
else:
|
327 |
+
self._qdot_u_map = None
|
328 |
+
self._f_k_implicit = self._f_k = Matrix()
|
329 |
+
self._k_ku_implicit = self._k_ku = Matrix()
|
330 |
+
self._k_kqdot_implicit = self._k_kqdot = Matrix()
|
331 |
+
|
332 |
+
def _form_fr(self, fl):
|
333 |
+
"""Form the generalized active force."""
|
334 |
+
if fl is not None and (len(fl) == 0 or not iterable(fl)):
|
335 |
+
raise ValueError('Force pairs must be supplied in an '
|
336 |
+
'non-empty iterable or None.')
|
337 |
+
|
338 |
+
N = self._inertial
|
339 |
+
# pull out relevant velocities for constructing partial velocities
|
340 |
+
vel_list, f_list = _f_list_parser(fl, N)
|
341 |
+
vel_list = [msubs(i, self._qdot_u_map) for i in vel_list]
|
342 |
+
f_list = [msubs(i, self._qdot_u_map) for i in f_list]
|
343 |
+
|
344 |
+
# Fill Fr with dot product of partial velocities and forces
|
345 |
+
o = len(self.u)
|
346 |
+
b = len(f_list)
|
347 |
+
FR = zeros(o, 1)
|
348 |
+
partials = partial_velocity(vel_list, self.u, N)
|
349 |
+
for i in range(o):
|
350 |
+
FR[i] = sum(partials[j][i] & f_list[j] for j in range(b))
|
351 |
+
|
352 |
+
# In case there are dependent speeds
|
353 |
+
if self._udep:
|
354 |
+
p = o - len(self._udep)
|
355 |
+
FRtilde = FR[:p, 0]
|
356 |
+
FRold = FR[p:o, 0]
|
357 |
+
FRtilde += self._Ars.T * FRold
|
358 |
+
FR = FRtilde
|
359 |
+
|
360 |
+
self._forcelist = fl
|
361 |
+
self._fr = FR
|
362 |
+
return FR
|
363 |
+
|
364 |
+
def _form_frstar(self, bl):
|
365 |
+
"""Form the generalized inertia force."""
|
366 |
+
|
367 |
+
if not iterable(bl):
|
368 |
+
raise TypeError('Bodies must be supplied in an iterable.')
|
369 |
+
|
370 |
+
t = dynamicsymbols._t
|
371 |
+
N = self._inertial
|
372 |
+
# Dicts setting things to zero
|
373 |
+
udot_zero = {i: 0 for i in self._udot}
|
374 |
+
uaux_zero = {i: 0 for i in self._uaux}
|
375 |
+
uauxdot = [diff(i, t) for i in self._uaux]
|
376 |
+
uauxdot_zero = {i: 0 for i in uauxdot}
|
377 |
+
# Dictionary of q' and q'' to u and u'
|
378 |
+
q_ddot_u_map = {k.diff(t): v.diff(t) for (k, v) in
|
379 |
+
self._qdot_u_map.items()}
|
380 |
+
q_ddot_u_map.update(self._qdot_u_map)
|
381 |
+
|
382 |
+
# Fill up the list of partials: format is a list with num elements
|
383 |
+
# equal to number of entries in body list. Each of these elements is a
|
384 |
+
# list - either of length 1 for the translational components of
|
385 |
+
# particles or of length 2 for the translational and rotational
|
386 |
+
# components of rigid bodies. The inner most list is the list of
|
387 |
+
# partial velocities.
|
388 |
+
def get_partial_velocity(body):
|
389 |
+
if isinstance(body, RigidBody):
|
390 |
+
vlist = [body.masscenter.vel(N), body.frame.ang_vel_in(N)]
|
391 |
+
elif isinstance(body, Particle):
|
392 |
+
vlist = [body.point.vel(N),]
|
393 |
+
else:
|
394 |
+
raise TypeError('The body list may only contain either '
|
395 |
+
'RigidBody or Particle as list elements.')
|
396 |
+
v = [msubs(vel, self._qdot_u_map) for vel in vlist]
|
397 |
+
return partial_velocity(v, self.u, N)
|
398 |
+
partials = [get_partial_velocity(body) for body in bl]
|
399 |
+
|
400 |
+
# Compute fr_star in two components:
|
401 |
+
# fr_star = -(MM*u' + nonMM)
|
402 |
+
o = len(self.u)
|
403 |
+
MM = zeros(o, o)
|
404 |
+
nonMM = zeros(o, 1)
|
405 |
+
zero_uaux = lambda expr: msubs(expr, uaux_zero)
|
406 |
+
zero_udot_uaux = lambda expr: msubs(msubs(expr, udot_zero), uaux_zero)
|
407 |
+
for i, body in enumerate(bl):
|
408 |
+
if isinstance(body, RigidBody):
|
409 |
+
M = zero_uaux(body.mass)
|
410 |
+
I = zero_uaux(body.central_inertia)
|
411 |
+
vel = zero_uaux(body.masscenter.vel(N))
|
412 |
+
omega = zero_uaux(body.frame.ang_vel_in(N))
|
413 |
+
acc = zero_udot_uaux(body.masscenter.acc(N))
|
414 |
+
inertial_force = (M.diff(t) * vel + M * acc)
|
415 |
+
inertial_torque = zero_uaux((I.dt(body.frame) & omega) +
|
416 |
+
msubs(I & body.frame.ang_acc_in(N), udot_zero) +
|
417 |
+
(omega ^ (I & omega)))
|
418 |
+
for j in range(o):
|
419 |
+
tmp_vel = zero_uaux(partials[i][0][j])
|
420 |
+
tmp_ang = zero_uaux(I & partials[i][1][j])
|
421 |
+
for k in range(o):
|
422 |
+
# translational
|
423 |
+
MM[j, k] += M * (tmp_vel & partials[i][0][k])
|
424 |
+
# rotational
|
425 |
+
MM[j, k] += (tmp_ang & partials[i][1][k])
|
426 |
+
nonMM[j] += inertial_force & partials[i][0][j]
|
427 |
+
nonMM[j] += inertial_torque & partials[i][1][j]
|
428 |
+
else:
|
429 |
+
M = zero_uaux(body.mass)
|
430 |
+
vel = zero_uaux(body.point.vel(N))
|
431 |
+
acc = zero_udot_uaux(body.point.acc(N))
|
432 |
+
inertial_force = (M.diff(t) * vel + M * acc)
|
433 |
+
for j in range(o):
|
434 |
+
temp = zero_uaux(partials[i][0][j])
|
435 |
+
for k in range(o):
|
436 |
+
MM[j, k] += M * (temp & partials[i][0][k])
|
437 |
+
nonMM[j] += inertial_force & partials[i][0][j]
|
438 |
+
# Compose fr_star out of MM and nonMM
|
439 |
+
MM = zero_uaux(msubs(MM, q_ddot_u_map))
|
440 |
+
nonMM = msubs(msubs(nonMM, q_ddot_u_map),
|
441 |
+
udot_zero, uauxdot_zero, uaux_zero)
|
442 |
+
fr_star = -(MM * msubs(Matrix(self._udot), uauxdot_zero) + nonMM)
|
443 |
+
|
444 |
+
# If there are dependent speeds, we need to find fr_star_tilde
|
445 |
+
if self._udep:
|
446 |
+
p = o - len(self._udep)
|
447 |
+
fr_star_ind = fr_star[:p, 0]
|
448 |
+
fr_star_dep = fr_star[p:o, 0]
|
449 |
+
fr_star = fr_star_ind + (self._Ars.T * fr_star_dep)
|
450 |
+
# Apply the same to MM
|
451 |
+
MMi = MM[:p, :]
|
452 |
+
MMd = MM[p:o, :]
|
453 |
+
MM = MMi + (self._Ars.T * MMd)
|
454 |
+
|
455 |
+
self._bodylist = bl
|
456 |
+
self._frstar = fr_star
|
457 |
+
self._k_d = MM
|
458 |
+
self._f_d = -msubs(self._fr + self._frstar, udot_zero)
|
459 |
+
return fr_star
|
460 |
+
|
461 |
+
def to_linearizer(self):
|
462 |
+
"""Returns an instance of the Linearizer class, initiated from the
|
463 |
+
data in the KanesMethod class. This may be more desirable than using
|
464 |
+
the linearize class method, as the Linearizer object will allow more
|
465 |
+
efficient recalculation (i.e. about varying operating points)."""
|
466 |
+
|
467 |
+
if (self._fr is None) or (self._frstar is None):
|
468 |
+
raise ValueError('Need to compute Fr, Fr* first.')
|
469 |
+
|
470 |
+
# Get required equation components. The Kane's method class breaks
|
471 |
+
# these into pieces. Need to reassemble
|
472 |
+
f_c = self._f_h
|
473 |
+
if self._f_nh and self._k_nh:
|
474 |
+
f_v = self._f_nh + self._k_nh*Matrix(self.u)
|
475 |
+
else:
|
476 |
+
f_v = Matrix()
|
477 |
+
if self._f_dnh and self._k_dnh:
|
478 |
+
f_a = self._f_dnh + self._k_dnh*Matrix(self._udot)
|
479 |
+
else:
|
480 |
+
f_a = Matrix()
|
481 |
+
# Dicts to sub to zero, for splitting up expressions
|
482 |
+
u_zero = {i: 0 for i in self.u}
|
483 |
+
ud_zero = {i: 0 for i in self._udot}
|
484 |
+
qd_zero = {i: 0 for i in self._qdot}
|
485 |
+
qd_u_zero = {i: 0 for i in Matrix([self._qdot, self.u])}
|
486 |
+
# Break the kinematic differential eqs apart into f_0 and f_1
|
487 |
+
f_0 = msubs(self._f_k, u_zero) + self._k_kqdot*Matrix(self._qdot)
|
488 |
+
f_1 = msubs(self._f_k, qd_zero) + self._k_ku*Matrix(self.u)
|
489 |
+
# Break the dynamic differential eqs into f_2 and f_3
|
490 |
+
f_2 = msubs(self._frstar, qd_u_zero)
|
491 |
+
f_3 = msubs(self._frstar, ud_zero) + self._fr
|
492 |
+
f_4 = zeros(len(f_2), 1)
|
493 |
+
|
494 |
+
# Get the required vector components
|
495 |
+
q = self.q
|
496 |
+
u = self.u
|
497 |
+
if self._qdep:
|
498 |
+
q_i = q[:-len(self._qdep)]
|
499 |
+
else:
|
500 |
+
q_i = q
|
501 |
+
q_d = self._qdep
|
502 |
+
if self._udep:
|
503 |
+
u_i = u[:-len(self._udep)]
|
504 |
+
else:
|
505 |
+
u_i = u
|
506 |
+
u_d = self._udep
|
507 |
+
|
508 |
+
# Form dictionary to set auxiliary speeds & their derivatives to 0.
|
509 |
+
uaux = self._uaux
|
510 |
+
uauxdot = uaux.diff(dynamicsymbols._t)
|
511 |
+
uaux_zero = {i: 0 for i in Matrix([uaux, uauxdot])}
|
512 |
+
|
513 |
+
# Checking for dynamic symbols outside the dynamic differential
|
514 |
+
# equations; throws error if there is.
|
515 |
+
sym_list = set(Matrix([q, self._qdot, u, self._udot, uaux, uauxdot]))
|
516 |
+
if any(find_dynamicsymbols(i, sym_list) for i in [self._k_kqdot,
|
517 |
+
self._k_ku, self._f_k, self._k_dnh, self._f_dnh, self._k_d]):
|
518 |
+
raise ValueError('Cannot have dynamicsymbols outside dynamic \
|
519 |
+
forcing vector.')
|
520 |
+
|
521 |
+
# Find all other dynamic symbols, forming the forcing vector r.
|
522 |
+
# Sort r to make it canonical.
|
523 |
+
r = list(find_dynamicsymbols(msubs(self._f_d, uaux_zero), sym_list))
|
524 |
+
r.sort(key=default_sort_key)
|
525 |
+
|
526 |
+
# Check for any derivatives of variables in r that are also found in r.
|
527 |
+
for i in r:
|
528 |
+
if diff(i, dynamicsymbols._t) in r:
|
529 |
+
raise ValueError('Cannot have derivatives of specified \
|
530 |
+
quantities when linearizing forcing terms.')
|
531 |
+
return Linearizer(f_0, f_1, f_2, f_3, f_4, f_c, f_v, f_a, q, u, q_i,
|
532 |
+
q_d, u_i, u_d, r)
|
533 |
+
|
534 |
+
# TODO : Remove `new_method` after 1.1 has been released.
|
535 |
+
def linearize(self, *, new_method=None, **kwargs):
|
536 |
+
""" Linearize the equations of motion about a symbolic operating point.
|
537 |
+
|
538 |
+
Explanation
|
539 |
+
===========
|
540 |
+
|
541 |
+
If kwarg A_and_B is False (default), returns M, A, B, r for the
|
542 |
+
linearized form, M*[q', u']^T = A*[q_ind, u_ind]^T + B*r.
|
543 |
+
|
544 |
+
If kwarg A_and_B is True, returns A, B, r for the linearized form
|
545 |
+
dx = A*x + B*r, where x = [q_ind, u_ind]^T. Note that this is
|
546 |
+
computationally intensive if there are many symbolic parameters. For
|
547 |
+
this reason, it may be more desirable to use the default A_and_B=False,
|
548 |
+
returning M, A, and B. Values may then be substituted in to these
|
549 |
+
matrices, and the state space form found as
|
550 |
+
A = P.T*M.inv()*A, B = P.T*M.inv()*B, where P = Linearizer.perm_mat.
|
551 |
+
|
552 |
+
In both cases, r is found as all dynamicsymbols in the equations of
|
553 |
+
motion that are not part of q, u, q', or u'. They are sorted in
|
554 |
+
canonical form.
|
555 |
+
|
556 |
+
The operating points may be also entered using the ``op_point`` kwarg.
|
557 |
+
This takes a dictionary of {symbol: value}, or a an iterable of such
|
558 |
+
dictionaries. The values may be numeric or symbolic. The more values
|
559 |
+
you can specify beforehand, the faster this computation will run.
|
560 |
+
|
561 |
+
For more documentation, please see the ``Linearizer`` class."""
|
562 |
+
linearizer = self.to_linearizer()
|
563 |
+
result = linearizer.linearize(**kwargs)
|
564 |
+
return result + (linearizer.r,)
|
565 |
+
|
566 |
+
def kanes_equations(self, bodies=None, loads=None):
|
567 |
+
""" Method to form Kane's equations, Fr + Fr* = 0.
|
568 |
+
|
569 |
+
Explanation
|
570 |
+
===========
|
571 |
+
|
572 |
+
Returns (Fr, Fr*). In the case where auxiliary generalized speeds are
|
573 |
+
present (say, s auxiliary speeds, o generalized speeds, and m motion
|
574 |
+
constraints) the length of the returned vectors will be o - m + s in
|
575 |
+
length. The first o - m equations will be the constrained Kane's
|
576 |
+
equations, then the s auxiliary Kane's equations. These auxiliary
|
577 |
+
equations can be accessed with the auxiliary_eqs property.
|
578 |
+
|
579 |
+
Parameters
|
580 |
+
==========
|
581 |
+
|
582 |
+
bodies : iterable
|
583 |
+
An iterable of all RigidBody's and Particle's in the system.
|
584 |
+
A system must have at least one body.
|
585 |
+
loads : iterable
|
586 |
+
Takes in an iterable of (Particle, Vector) or (ReferenceFrame, Vector)
|
587 |
+
tuples which represent the force at a point or torque on a frame.
|
588 |
+
Must be either a non-empty iterable of tuples or None which corresponds
|
589 |
+
to a system with no constraints.
|
590 |
+
"""
|
591 |
+
if bodies is None:
|
592 |
+
bodies = self.bodies
|
593 |
+
if loads is None and self._forcelist is not None:
|
594 |
+
loads = self._forcelist
|
595 |
+
if loads == []:
|
596 |
+
loads = None
|
597 |
+
if not self._k_kqdot:
|
598 |
+
raise AttributeError('Create an instance of KanesMethod with '
|
599 |
+
'kinematic differential equations to use this method.')
|
600 |
+
fr = self._form_fr(loads)
|
601 |
+
frstar = self._form_frstar(bodies)
|
602 |
+
if self._uaux:
|
603 |
+
if not self._udep:
|
604 |
+
km = KanesMethod(self._inertial, self.q, self._uaux,
|
605 |
+
u_auxiliary=self._uaux)
|
606 |
+
else:
|
607 |
+
km = KanesMethod(self._inertial, self.q, self._uaux,
|
608 |
+
u_auxiliary=self._uaux, u_dependent=self._udep,
|
609 |
+
velocity_constraints=(self._k_nh * self.u +
|
610 |
+
self._f_nh),
|
611 |
+
acceleration_constraints=(self._k_dnh * self._udot +
|
612 |
+
self._f_dnh)
|
613 |
+
)
|
614 |
+
km._qdot_u_map = self._qdot_u_map
|
615 |
+
self._km = km
|
616 |
+
fraux = km._form_fr(loads)
|
617 |
+
frstaraux = km._form_frstar(bodies)
|
618 |
+
self._aux_eq = fraux + frstaraux
|
619 |
+
self._fr = fr.col_join(fraux)
|
620 |
+
self._frstar = frstar.col_join(frstaraux)
|
621 |
+
return (self._fr, self._frstar)
|
622 |
+
|
623 |
+
def _form_eoms(self):
|
624 |
+
fr, frstar = self.kanes_equations(self.bodylist, self.forcelist)
|
625 |
+
return fr + frstar
|
626 |
+
|
627 |
+
def rhs(self, inv_method=None):
|
628 |
+
"""Returns the system's equations of motion in first order form. The
|
629 |
+
output is the right hand side of::
|
630 |
+
|
631 |
+
x' = |q'| =: f(q, u, r, p, t)
|
632 |
+
|u'|
|
633 |
+
|
634 |
+
The right hand side is what is needed by most numerical ODE
|
635 |
+
integrators.
|
636 |
+
|
637 |
+
Parameters
|
638 |
+
==========
|
639 |
+
|
640 |
+
inv_method : str
|
641 |
+
The specific sympy inverse matrix calculation method to use. For a
|
642 |
+
list of valid methods, see
|
643 |
+
:meth:`~sympy.matrices.matrices.MatrixBase.inv`
|
644 |
+
|
645 |
+
"""
|
646 |
+
rhs = zeros(len(self.q) + len(self.u), 1)
|
647 |
+
kdes = self.kindiffdict()
|
648 |
+
for i, q_i in enumerate(self.q):
|
649 |
+
rhs[i] = kdes[q_i.diff()]
|
650 |
+
|
651 |
+
if inv_method is None:
|
652 |
+
rhs[len(self.q):, 0] = self.mass_matrix.LUsolve(self.forcing)
|
653 |
+
else:
|
654 |
+
rhs[len(self.q):, 0] = (self.mass_matrix.inv(inv_method,
|
655 |
+
try_block_diag=True) *
|
656 |
+
self.forcing)
|
657 |
+
|
658 |
+
return rhs
|
659 |
+
|
660 |
+
def kindiffdict(self):
|
661 |
+
"""Returns a dictionary mapping q' to u."""
|
662 |
+
if not self._qdot_u_map:
|
663 |
+
raise AttributeError('Create an instance of KanesMethod with '
|
664 |
+
'kinematic differential equations to use this method.')
|
665 |
+
return self._qdot_u_map
|
666 |
+
|
667 |
+
@property
|
668 |
+
def auxiliary_eqs(self):
|
669 |
+
"""A matrix containing the auxiliary equations."""
|
670 |
+
if not self._fr or not self._frstar:
|
671 |
+
raise ValueError('Need to compute Fr, Fr* first.')
|
672 |
+
if not self._uaux:
|
673 |
+
raise ValueError('No auxiliary speeds have been declared.')
|
674 |
+
return self._aux_eq
|
675 |
+
|
676 |
+
@property
|
677 |
+
def mass_matrix_kin(self):
|
678 |
+
r"""The kinematic "mass matrix" $\mathbf{k_{k\dot{q}}}$ of the system."""
|
679 |
+
return self._k_kqdot if self.explicit_kinematics else self._k_kqdot_implicit
|
680 |
+
|
681 |
+
@property
|
682 |
+
def forcing_kin(self):
|
683 |
+
"""The kinematic "forcing vector" of the system."""
|
684 |
+
if self.explicit_kinematics:
|
685 |
+
return -(self._k_ku * Matrix(self.u) + self._f_k)
|
686 |
+
else:
|
687 |
+
return -(self._k_ku_implicit * Matrix(self.u) + self._f_k_implicit)
|
688 |
+
|
689 |
+
@property
|
690 |
+
def mass_matrix(self):
|
691 |
+
"""The mass matrix of the system."""
|
692 |
+
if not self._fr or not self._frstar:
|
693 |
+
raise ValueError('Need to compute Fr, Fr* first.')
|
694 |
+
return Matrix([self._k_d, self._k_dnh])
|
695 |
+
|
696 |
+
@property
|
697 |
+
def forcing(self):
|
698 |
+
"""The forcing vector of the system."""
|
699 |
+
if not self._fr or not self._frstar:
|
700 |
+
raise ValueError('Need to compute Fr, Fr* first.')
|
701 |
+
return -Matrix([self._f_d, self._f_dnh])
|
702 |
+
|
703 |
+
@property
|
704 |
+
def mass_matrix_full(self):
|
705 |
+
"""The mass matrix of the system, augmented by the kinematic
|
706 |
+
differential equations in explicit or implicit form."""
|
707 |
+
if not self._fr or not self._frstar:
|
708 |
+
raise ValueError('Need to compute Fr, Fr* first.')
|
709 |
+
o, n = len(self.u), len(self.q)
|
710 |
+
return (self.mass_matrix_kin.row_join(zeros(n, o))).col_join(
|
711 |
+
zeros(o, n).row_join(self.mass_matrix))
|
712 |
+
|
713 |
+
@property
|
714 |
+
def forcing_full(self):
|
715 |
+
"""The forcing vector of the system, augmented by the kinematic
|
716 |
+
differential equations in explicit or implicit form."""
|
717 |
+
return Matrix([self.forcing_kin, self.forcing])
|
718 |
+
|
719 |
+
@property
|
720 |
+
def q(self):
|
721 |
+
return self._q
|
722 |
+
|
723 |
+
@property
|
724 |
+
def u(self):
|
725 |
+
return self._u
|
726 |
+
|
727 |
+
@property
|
728 |
+
def bodylist(self):
|
729 |
+
return self._bodylist
|
730 |
+
|
731 |
+
@property
|
732 |
+
def forcelist(self):
|
733 |
+
return self._forcelist
|
734 |
+
|
735 |
+
@property
|
736 |
+
def bodies(self):
|
737 |
+
return self._bodylist
|
738 |
+
|
739 |
+
@property
|
740 |
+
def loads(self):
|
741 |
+
return self._forcelist
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/lagrange.py
ADDED
@@ -0,0 +1,477 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.core.backend import diff, zeros, Matrix, eye, sympify
|
2 |
+
from sympy.core.sorting import default_sort_key
|
3 |
+
from sympy.physics.vector import dynamicsymbols, ReferenceFrame
|
4 |
+
from sympy.physics.mechanics.method import _Methods
|
5 |
+
from sympy.physics.mechanics.functions import (
|
6 |
+
find_dynamicsymbols, msubs, _f_list_parser, _validate_coordinates)
|
7 |
+
from sympy.physics.mechanics.linearize import Linearizer
|
8 |
+
from sympy.utilities.iterables import iterable
|
9 |
+
|
10 |
+
__all__ = ['LagrangesMethod']
|
11 |
+
|
12 |
+
|
13 |
+
class LagrangesMethod(_Methods):
|
14 |
+
"""Lagrange's method object.
|
15 |
+
|
16 |
+
Explanation
|
17 |
+
===========
|
18 |
+
|
19 |
+
This object generates the equations of motion in a two step procedure. The
|
20 |
+
first step involves the initialization of LagrangesMethod by supplying the
|
21 |
+
Lagrangian and the generalized coordinates, at the bare minimum. If there
|
22 |
+
are any constraint equations, they can be supplied as keyword arguments.
|
23 |
+
The Lagrange multipliers are automatically generated and are equal in
|
24 |
+
number to the constraint equations. Similarly any non-conservative forces
|
25 |
+
can be supplied in an iterable (as described below and also shown in the
|
26 |
+
example) along with a ReferenceFrame. This is also discussed further in the
|
27 |
+
__init__ method.
|
28 |
+
|
29 |
+
Attributes
|
30 |
+
==========
|
31 |
+
|
32 |
+
q, u : Matrix
|
33 |
+
Matrices of the generalized coordinates and speeds
|
34 |
+
loads : iterable
|
35 |
+
Iterable of (Point, vector) or (ReferenceFrame, vector) tuples
|
36 |
+
describing the forces on the system.
|
37 |
+
bodies : iterable
|
38 |
+
Iterable containing the rigid bodies and particles of the system.
|
39 |
+
mass_matrix : Matrix
|
40 |
+
The system's mass matrix
|
41 |
+
forcing : Matrix
|
42 |
+
The system's forcing vector
|
43 |
+
mass_matrix_full : Matrix
|
44 |
+
The "mass matrix" for the qdot's, qdoubledot's, and the
|
45 |
+
lagrange multipliers (lam)
|
46 |
+
forcing_full : Matrix
|
47 |
+
The forcing vector for the qdot's, qdoubledot's and
|
48 |
+
lagrange multipliers (lam)
|
49 |
+
|
50 |
+
Examples
|
51 |
+
========
|
52 |
+
|
53 |
+
This is a simple example for a one degree of freedom translational
|
54 |
+
spring-mass-damper.
|
55 |
+
|
56 |
+
In this example, we first need to do the kinematics.
|
57 |
+
This involves creating generalized coordinates and their derivatives.
|
58 |
+
Then we create a point and set its velocity in a frame.
|
59 |
+
|
60 |
+
>>> from sympy.physics.mechanics import LagrangesMethod, Lagrangian
|
61 |
+
>>> from sympy.physics.mechanics import ReferenceFrame, Particle, Point
|
62 |
+
>>> from sympy.physics.mechanics import dynamicsymbols
|
63 |
+
>>> from sympy import symbols
|
64 |
+
>>> q = dynamicsymbols('q')
|
65 |
+
>>> qd = dynamicsymbols('q', 1)
|
66 |
+
>>> m, k, b = symbols('m k b')
|
67 |
+
>>> N = ReferenceFrame('N')
|
68 |
+
>>> P = Point('P')
|
69 |
+
>>> P.set_vel(N, qd * N.x)
|
70 |
+
|
71 |
+
We need to then prepare the information as required by LagrangesMethod to
|
72 |
+
generate equations of motion.
|
73 |
+
First we create the Particle, which has a point attached to it.
|
74 |
+
Following this the lagrangian is created from the kinetic and potential
|
75 |
+
energies.
|
76 |
+
Then, an iterable of nonconservative forces/torques must be constructed,
|
77 |
+
where each item is a (Point, Vector) or (ReferenceFrame, Vector) tuple,
|
78 |
+
with the Vectors representing the nonconservative forces or torques.
|
79 |
+
|
80 |
+
>>> Pa = Particle('Pa', P, m)
|
81 |
+
>>> Pa.potential_energy = k * q**2 / 2.0
|
82 |
+
>>> L = Lagrangian(N, Pa)
|
83 |
+
>>> fl = [(P, -b * qd * N.x)]
|
84 |
+
|
85 |
+
Finally we can generate the equations of motion.
|
86 |
+
First we create the LagrangesMethod object. To do this one must supply
|
87 |
+
the Lagrangian, and the generalized coordinates. The constraint equations,
|
88 |
+
the forcelist, and the inertial frame may also be provided, if relevant.
|
89 |
+
Next we generate Lagrange's equations of motion, such that:
|
90 |
+
Lagrange's equations of motion = 0.
|
91 |
+
We have the equations of motion at this point.
|
92 |
+
|
93 |
+
>>> l = LagrangesMethod(L, [q], forcelist = fl, frame = N)
|
94 |
+
>>> print(l.form_lagranges_equations())
|
95 |
+
Matrix([[b*Derivative(q(t), t) + 1.0*k*q(t) + m*Derivative(q(t), (t, 2))]])
|
96 |
+
|
97 |
+
We can also solve for the states using the 'rhs' method.
|
98 |
+
|
99 |
+
>>> print(l.rhs())
|
100 |
+
Matrix([[Derivative(q(t), t)], [(-b*Derivative(q(t), t) - 1.0*k*q(t))/m]])
|
101 |
+
|
102 |
+
Please refer to the docstrings on each method for more details.
|
103 |
+
"""
|
104 |
+
|
105 |
+
def __init__(self, Lagrangian, qs, forcelist=None, bodies=None, frame=None,
|
106 |
+
hol_coneqs=None, nonhol_coneqs=None):
|
107 |
+
"""Supply the following for the initialization of LagrangesMethod.
|
108 |
+
|
109 |
+
Lagrangian : Sympifyable
|
110 |
+
|
111 |
+
qs : array_like
|
112 |
+
The generalized coordinates
|
113 |
+
|
114 |
+
hol_coneqs : array_like, optional
|
115 |
+
The holonomic constraint equations
|
116 |
+
|
117 |
+
nonhol_coneqs : array_like, optional
|
118 |
+
The nonholonomic constraint equations
|
119 |
+
|
120 |
+
forcelist : iterable, optional
|
121 |
+
Takes an iterable of (Point, Vector) or (ReferenceFrame, Vector)
|
122 |
+
tuples which represent the force at a point or torque on a frame.
|
123 |
+
This feature is primarily to account for the nonconservative forces
|
124 |
+
and/or moments.
|
125 |
+
|
126 |
+
bodies : iterable, optional
|
127 |
+
Takes an iterable containing the rigid bodies and particles of the
|
128 |
+
system.
|
129 |
+
|
130 |
+
frame : ReferenceFrame, optional
|
131 |
+
Supply the inertial frame. This is used to determine the
|
132 |
+
generalized forces due to non-conservative forces.
|
133 |
+
"""
|
134 |
+
|
135 |
+
self._L = Matrix([sympify(Lagrangian)])
|
136 |
+
self.eom = None
|
137 |
+
self._m_cd = Matrix() # Mass Matrix of differentiated coneqs
|
138 |
+
self._m_d = Matrix() # Mass Matrix of dynamic equations
|
139 |
+
self._f_cd = Matrix() # Forcing part of the diff coneqs
|
140 |
+
self._f_d = Matrix() # Forcing part of the dynamic equations
|
141 |
+
self.lam_coeffs = Matrix() # The coeffecients of the multipliers
|
142 |
+
|
143 |
+
forcelist = forcelist if forcelist else []
|
144 |
+
if not iterable(forcelist):
|
145 |
+
raise TypeError('Force pairs must be supplied in an iterable.')
|
146 |
+
self._forcelist = forcelist
|
147 |
+
if frame and not isinstance(frame, ReferenceFrame):
|
148 |
+
raise TypeError('frame must be a valid ReferenceFrame')
|
149 |
+
self._bodies = bodies
|
150 |
+
self.inertial = frame
|
151 |
+
|
152 |
+
self.lam_vec = Matrix()
|
153 |
+
|
154 |
+
self._term1 = Matrix()
|
155 |
+
self._term2 = Matrix()
|
156 |
+
self._term3 = Matrix()
|
157 |
+
self._term4 = Matrix()
|
158 |
+
|
159 |
+
# Creating the qs, qdots and qdoubledots
|
160 |
+
if not iterable(qs):
|
161 |
+
raise TypeError('Generalized coordinates must be an iterable')
|
162 |
+
self._q = Matrix(qs)
|
163 |
+
self._qdots = self.q.diff(dynamicsymbols._t)
|
164 |
+
self._qdoubledots = self._qdots.diff(dynamicsymbols._t)
|
165 |
+
_validate_coordinates(self.q)
|
166 |
+
|
167 |
+
mat_build = lambda x: Matrix(x) if x else Matrix()
|
168 |
+
hol_coneqs = mat_build(hol_coneqs)
|
169 |
+
nonhol_coneqs = mat_build(nonhol_coneqs)
|
170 |
+
self.coneqs = Matrix([hol_coneqs.diff(dynamicsymbols._t),
|
171 |
+
nonhol_coneqs])
|
172 |
+
self._hol_coneqs = hol_coneqs
|
173 |
+
|
174 |
+
def form_lagranges_equations(self):
|
175 |
+
"""Method to form Lagrange's equations of motion.
|
176 |
+
|
177 |
+
Returns a vector of equations of motion using Lagrange's equations of
|
178 |
+
the second kind.
|
179 |
+
"""
|
180 |
+
|
181 |
+
qds = self._qdots
|
182 |
+
qdd_zero = {i: 0 for i in self._qdoubledots}
|
183 |
+
n = len(self.q)
|
184 |
+
|
185 |
+
# Internally we represent the EOM as four terms:
|
186 |
+
# EOM = term1 - term2 - term3 - term4 = 0
|
187 |
+
|
188 |
+
# First term
|
189 |
+
self._term1 = self._L.jacobian(qds)
|
190 |
+
self._term1 = self._term1.diff(dynamicsymbols._t).T
|
191 |
+
|
192 |
+
# Second term
|
193 |
+
self._term2 = self._L.jacobian(self.q).T
|
194 |
+
|
195 |
+
# Third term
|
196 |
+
if self.coneqs:
|
197 |
+
coneqs = self.coneqs
|
198 |
+
m = len(coneqs)
|
199 |
+
# Creating the multipliers
|
200 |
+
self.lam_vec = Matrix(dynamicsymbols('lam1:' + str(m + 1)))
|
201 |
+
self.lam_coeffs = -coneqs.jacobian(qds)
|
202 |
+
self._term3 = self.lam_coeffs.T * self.lam_vec
|
203 |
+
# Extracting the coeffecients of the qdds from the diff coneqs
|
204 |
+
diffconeqs = coneqs.diff(dynamicsymbols._t)
|
205 |
+
self._m_cd = diffconeqs.jacobian(self._qdoubledots)
|
206 |
+
# The remaining terms i.e. the 'forcing' terms in diff coneqs
|
207 |
+
self._f_cd = -diffconeqs.subs(qdd_zero)
|
208 |
+
else:
|
209 |
+
self._term3 = zeros(n, 1)
|
210 |
+
|
211 |
+
# Fourth term
|
212 |
+
if self.forcelist:
|
213 |
+
N = self.inertial
|
214 |
+
self._term4 = zeros(n, 1)
|
215 |
+
for i, qd in enumerate(qds):
|
216 |
+
flist = zip(*_f_list_parser(self.forcelist, N))
|
217 |
+
self._term4[i] = sum(v.diff(qd, N) & f for (v, f) in flist)
|
218 |
+
else:
|
219 |
+
self._term4 = zeros(n, 1)
|
220 |
+
|
221 |
+
# Form the dynamic mass and forcing matrices
|
222 |
+
without_lam = self._term1 - self._term2 - self._term4
|
223 |
+
self._m_d = without_lam.jacobian(self._qdoubledots)
|
224 |
+
self._f_d = -without_lam.subs(qdd_zero)
|
225 |
+
|
226 |
+
# Form the EOM
|
227 |
+
self.eom = without_lam - self._term3
|
228 |
+
return self.eom
|
229 |
+
|
230 |
+
def _form_eoms(self):
|
231 |
+
return self.form_lagranges_equations()
|
232 |
+
|
233 |
+
@property
|
234 |
+
def mass_matrix(self):
|
235 |
+
"""Returns the mass matrix, which is augmented by the Lagrange
|
236 |
+
multipliers, if necessary.
|
237 |
+
|
238 |
+
Explanation
|
239 |
+
===========
|
240 |
+
|
241 |
+
If the system is described by 'n' generalized coordinates and there are
|
242 |
+
no constraint equations then an n X n matrix is returned.
|
243 |
+
|
244 |
+
If there are 'n' generalized coordinates and 'm' constraint equations
|
245 |
+
have been supplied during initialization then an n X (n+m) matrix is
|
246 |
+
returned. The (n + m - 1)th and (n + m)th columns contain the
|
247 |
+
coefficients of the Lagrange multipliers.
|
248 |
+
"""
|
249 |
+
|
250 |
+
if self.eom is None:
|
251 |
+
raise ValueError('Need to compute the equations of motion first')
|
252 |
+
if self.coneqs:
|
253 |
+
return (self._m_d).row_join(self.lam_coeffs.T)
|
254 |
+
else:
|
255 |
+
return self._m_d
|
256 |
+
|
257 |
+
@property
|
258 |
+
def mass_matrix_full(self):
|
259 |
+
"""Augments the coefficients of qdots to the mass_matrix."""
|
260 |
+
|
261 |
+
if self.eom is None:
|
262 |
+
raise ValueError('Need to compute the equations of motion first')
|
263 |
+
n = len(self.q)
|
264 |
+
m = len(self.coneqs)
|
265 |
+
row1 = eye(n).row_join(zeros(n, n + m))
|
266 |
+
row2 = zeros(n, n).row_join(self.mass_matrix)
|
267 |
+
if self.coneqs:
|
268 |
+
row3 = zeros(m, n).row_join(self._m_cd).row_join(zeros(m, m))
|
269 |
+
return row1.col_join(row2).col_join(row3)
|
270 |
+
else:
|
271 |
+
return row1.col_join(row2)
|
272 |
+
|
273 |
+
@property
|
274 |
+
def forcing(self):
|
275 |
+
"""Returns the forcing vector from 'lagranges_equations' method."""
|
276 |
+
|
277 |
+
if self.eom is None:
|
278 |
+
raise ValueError('Need to compute the equations of motion first')
|
279 |
+
return self._f_d
|
280 |
+
|
281 |
+
@property
|
282 |
+
def forcing_full(self):
|
283 |
+
"""Augments qdots to the forcing vector above."""
|
284 |
+
|
285 |
+
if self.eom is None:
|
286 |
+
raise ValueError('Need to compute the equations of motion first')
|
287 |
+
if self.coneqs:
|
288 |
+
return self._qdots.col_join(self.forcing).col_join(self._f_cd)
|
289 |
+
else:
|
290 |
+
return self._qdots.col_join(self.forcing)
|
291 |
+
|
292 |
+
def to_linearizer(self, q_ind=None, qd_ind=None, q_dep=None, qd_dep=None):
|
293 |
+
"""Returns an instance of the Linearizer class, initiated from the
|
294 |
+
data in the LagrangesMethod class. This may be more desirable than using
|
295 |
+
the linearize class method, as the Linearizer object will allow more
|
296 |
+
efficient recalculation (i.e. about varying operating points).
|
297 |
+
|
298 |
+
Parameters
|
299 |
+
==========
|
300 |
+
|
301 |
+
q_ind, qd_ind : array_like, optional
|
302 |
+
The independent generalized coordinates and speeds.
|
303 |
+
q_dep, qd_dep : array_like, optional
|
304 |
+
The dependent generalized coordinates and speeds.
|
305 |
+
"""
|
306 |
+
|
307 |
+
# Compose vectors
|
308 |
+
t = dynamicsymbols._t
|
309 |
+
q = self.q
|
310 |
+
u = self._qdots
|
311 |
+
ud = u.diff(t)
|
312 |
+
# Get vector of lagrange multipliers
|
313 |
+
lams = self.lam_vec
|
314 |
+
|
315 |
+
mat_build = lambda x: Matrix(x) if x else Matrix()
|
316 |
+
q_i = mat_build(q_ind)
|
317 |
+
q_d = mat_build(q_dep)
|
318 |
+
u_i = mat_build(qd_ind)
|
319 |
+
u_d = mat_build(qd_dep)
|
320 |
+
|
321 |
+
# Compose general form equations
|
322 |
+
f_c = self._hol_coneqs
|
323 |
+
f_v = self.coneqs
|
324 |
+
f_a = f_v.diff(t)
|
325 |
+
f_0 = u
|
326 |
+
f_1 = -u
|
327 |
+
f_2 = self._term1
|
328 |
+
f_3 = -(self._term2 + self._term4)
|
329 |
+
f_4 = -self._term3
|
330 |
+
|
331 |
+
# Check that there are an appropriate number of independent and
|
332 |
+
# dependent coordinates
|
333 |
+
if len(q_d) != len(f_c) or len(u_d) != len(f_v):
|
334 |
+
raise ValueError(("Must supply {:} dependent coordinates, and " +
|
335 |
+
"{:} dependent speeds").format(len(f_c), len(f_v)))
|
336 |
+
if set(Matrix([q_i, q_d])) != set(q):
|
337 |
+
raise ValueError("Must partition q into q_ind and q_dep, with " +
|
338 |
+
"no extra or missing symbols.")
|
339 |
+
if set(Matrix([u_i, u_d])) != set(u):
|
340 |
+
raise ValueError("Must partition qd into qd_ind and qd_dep, " +
|
341 |
+
"with no extra or missing symbols.")
|
342 |
+
|
343 |
+
# Find all other dynamic symbols, forming the forcing vector r.
|
344 |
+
# Sort r to make it canonical.
|
345 |
+
insyms = set(Matrix([q, u, ud, lams]))
|
346 |
+
r = list(find_dynamicsymbols(f_3, insyms))
|
347 |
+
r.sort(key=default_sort_key)
|
348 |
+
# Check for any derivatives of variables in r that are also found in r.
|
349 |
+
for i in r:
|
350 |
+
if diff(i, dynamicsymbols._t) in r:
|
351 |
+
raise ValueError('Cannot have derivatives of specified \
|
352 |
+
quantities when linearizing forcing terms.')
|
353 |
+
|
354 |
+
return Linearizer(f_0, f_1, f_2, f_3, f_4, f_c, f_v, f_a, q, u, q_i,
|
355 |
+
q_d, u_i, u_d, r, lams)
|
356 |
+
|
357 |
+
def linearize(self, q_ind=None, qd_ind=None, q_dep=None, qd_dep=None,
|
358 |
+
**kwargs):
|
359 |
+
"""Linearize the equations of motion about a symbolic operating point.
|
360 |
+
|
361 |
+
Explanation
|
362 |
+
===========
|
363 |
+
|
364 |
+
If kwarg A_and_B is False (default), returns M, A, B, r for the
|
365 |
+
linearized form, M*[q', u']^T = A*[q_ind, u_ind]^T + B*r.
|
366 |
+
|
367 |
+
If kwarg A_and_B is True, returns A, B, r for the linearized form
|
368 |
+
dx = A*x + B*r, where x = [q_ind, u_ind]^T. Note that this is
|
369 |
+
computationally intensive if there are many symbolic parameters. For
|
370 |
+
this reason, it may be more desirable to use the default A_and_B=False,
|
371 |
+
returning M, A, and B. Values may then be substituted in to these
|
372 |
+
matrices, and the state space form found as
|
373 |
+
A = P.T*M.inv()*A, B = P.T*M.inv()*B, where P = Linearizer.perm_mat.
|
374 |
+
|
375 |
+
In both cases, r is found as all dynamicsymbols in the equations of
|
376 |
+
motion that are not part of q, u, q', or u'. They are sorted in
|
377 |
+
canonical form.
|
378 |
+
|
379 |
+
The operating points may be also entered using the ``op_point`` kwarg.
|
380 |
+
This takes a dictionary of {symbol: value}, or a an iterable of such
|
381 |
+
dictionaries. The values may be numeric or symbolic. The more values
|
382 |
+
you can specify beforehand, the faster this computation will run.
|
383 |
+
|
384 |
+
For more documentation, please see the ``Linearizer`` class."""
|
385 |
+
|
386 |
+
linearizer = self.to_linearizer(q_ind, qd_ind, q_dep, qd_dep)
|
387 |
+
result = linearizer.linearize(**kwargs)
|
388 |
+
return result + (linearizer.r,)
|
389 |
+
|
390 |
+
def solve_multipliers(self, op_point=None, sol_type='dict'):
|
391 |
+
"""Solves for the values of the lagrange multipliers symbolically at
|
392 |
+
the specified operating point.
|
393 |
+
|
394 |
+
Parameters
|
395 |
+
==========
|
396 |
+
|
397 |
+
op_point : dict or iterable of dicts, optional
|
398 |
+
Point at which to solve at. The operating point is specified as
|
399 |
+
a dictionary or iterable of dictionaries of {symbol: value}. The
|
400 |
+
value may be numeric or symbolic itself.
|
401 |
+
|
402 |
+
sol_type : str, optional
|
403 |
+
Solution return type. Valid options are:
|
404 |
+
- 'dict': A dict of {symbol : value} (default)
|
405 |
+
- 'Matrix': An ordered column matrix of the solution
|
406 |
+
"""
|
407 |
+
|
408 |
+
# Determine number of multipliers
|
409 |
+
k = len(self.lam_vec)
|
410 |
+
if k == 0:
|
411 |
+
raise ValueError("System has no lagrange multipliers to solve for.")
|
412 |
+
# Compose dict of operating conditions
|
413 |
+
if isinstance(op_point, dict):
|
414 |
+
op_point_dict = op_point
|
415 |
+
elif iterable(op_point):
|
416 |
+
op_point_dict = {}
|
417 |
+
for op in op_point:
|
418 |
+
op_point_dict.update(op)
|
419 |
+
elif op_point is None:
|
420 |
+
op_point_dict = {}
|
421 |
+
else:
|
422 |
+
raise TypeError("op_point must be either a dictionary or an "
|
423 |
+
"iterable of dictionaries.")
|
424 |
+
# Compose the system to be solved
|
425 |
+
mass_matrix = self.mass_matrix.col_join(-self.lam_coeffs.row_join(
|
426 |
+
zeros(k, k)))
|
427 |
+
force_matrix = self.forcing.col_join(self._f_cd)
|
428 |
+
# Sub in the operating point
|
429 |
+
mass_matrix = msubs(mass_matrix, op_point_dict)
|
430 |
+
force_matrix = msubs(force_matrix, op_point_dict)
|
431 |
+
# Solve for the multipliers
|
432 |
+
sol_list = mass_matrix.LUsolve(-force_matrix)[-k:]
|
433 |
+
if sol_type == 'dict':
|
434 |
+
return dict(zip(self.lam_vec, sol_list))
|
435 |
+
elif sol_type == 'Matrix':
|
436 |
+
return Matrix(sol_list)
|
437 |
+
else:
|
438 |
+
raise ValueError("Unknown sol_type {:}.".format(sol_type))
|
439 |
+
|
440 |
+
def rhs(self, inv_method=None, **kwargs):
|
441 |
+
"""Returns equations that can be solved numerically.
|
442 |
+
|
443 |
+
Parameters
|
444 |
+
==========
|
445 |
+
|
446 |
+
inv_method : str
|
447 |
+
The specific sympy inverse matrix calculation method to use. For a
|
448 |
+
list of valid methods, see
|
449 |
+
:meth:`~sympy.matrices.matrices.MatrixBase.inv`
|
450 |
+
"""
|
451 |
+
|
452 |
+
if inv_method is None:
|
453 |
+
self._rhs = self.mass_matrix_full.LUsolve(self.forcing_full)
|
454 |
+
else:
|
455 |
+
self._rhs = (self.mass_matrix_full.inv(inv_method,
|
456 |
+
try_block_diag=True) * self.forcing_full)
|
457 |
+
return self._rhs
|
458 |
+
|
459 |
+
@property
|
460 |
+
def q(self):
|
461 |
+
return self._q
|
462 |
+
|
463 |
+
@property
|
464 |
+
def u(self):
|
465 |
+
return self._qdots
|
466 |
+
|
467 |
+
@property
|
468 |
+
def bodies(self):
|
469 |
+
return self._bodies
|
470 |
+
|
471 |
+
@property
|
472 |
+
def forcelist(self):
|
473 |
+
return self._forcelist
|
474 |
+
|
475 |
+
@property
|
476 |
+
def loads(self):
|
477 |
+
return self._forcelist
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/linearize.py
ADDED
@@ -0,0 +1,443 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
__all__ = ['Linearizer']
|
2 |
+
|
3 |
+
from sympy.core.backend import Matrix, eye, zeros
|
4 |
+
from sympy.core.symbol import Dummy
|
5 |
+
from sympy.utilities.iterables import flatten
|
6 |
+
from sympy.physics.vector import dynamicsymbols
|
7 |
+
from sympy.physics.mechanics.functions import msubs
|
8 |
+
|
9 |
+
from collections import namedtuple
|
10 |
+
from collections.abc import Iterable
|
11 |
+
|
12 |
+
class Linearizer:
|
13 |
+
"""This object holds the general model form for a dynamic system.
|
14 |
+
This model is used for computing the linearized form of the system,
|
15 |
+
while properly dealing with constraints leading to dependent
|
16 |
+
coordinates and speeds.
|
17 |
+
|
18 |
+
Attributes
|
19 |
+
==========
|
20 |
+
|
21 |
+
f_0, f_1, f_2, f_3, f_4, f_c, f_v, f_a : Matrix
|
22 |
+
Matrices holding the general system form.
|
23 |
+
q, u, r : Matrix
|
24 |
+
Matrices holding the generalized coordinates, speeds, and
|
25 |
+
input vectors.
|
26 |
+
q_i, u_i : Matrix
|
27 |
+
Matrices of the independent generalized coordinates and speeds.
|
28 |
+
q_d, u_d : Matrix
|
29 |
+
Matrices of the dependent generalized coordinates and speeds.
|
30 |
+
perm_mat : Matrix
|
31 |
+
Permutation matrix such that [q_ind, u_ind]^T = perm_mat*[q, u]^T
|
32 |
+
"""
|
33 |
+
|
34 |
+
def __init__(self, f_0, f_1, f_2, f_3, f_4, f_c, f_v, f_a, q, u,
|
35 |
+
q_i=None, q_d=None, u_i=None, u_d=None, r=None, lams=None):
|
36 |
+
"""
|
37 |
+
Parameters
|
38 |
+
==========
|
39 |
+
|
40 |
+
f_0, f_1, f_2, f_3, f_4, f_c, f_v, f_a : array_like
|
41 |
+
System of equations holding the general system form.
|
42 |
+
Supply empty array or Matrix if the parameter
|
43 |
+
does not exist.
|
44 |
+
q : array_like
|
45 |
+
The generalized coordinates.
|
46 |
+
u : array_like
|
47 |
+
The generalized speeds
|
48 |
+
q_i, u_i : array_like, optional
|
49 |
+
The independent generalized coordinates and speeds.
|
50 |
+
q_d, u_d : array_like, optional
|
51 |
+
The dependent generalized coordinates and speeds.
|
52 |
+
r : array_like, optional
|
53 |
+
The input variables.
|
54 |
+
lams : array_like, optional
|
55 |
+
The lagrange multipliers
|
56 |
+
"""
|
57 |
+
|
58 |
+
# Generalized equation form
|
59 |
+
self.f_0 = Matrix(f_0)
|
60 |
+
self.f_1 = Matrix(f_1)
|
61 |
+
self.f_2 = Matrix(f_2)
|
62 |
+
self.f_3 = Matrix(f_3)
|
63 |
+
self.f_4 = Matrix(f_4)
|
64 |
+
self.f_c = Matrix(f_c)
|
65 |
+
self.f_v = Matrix(f_v)
|
66 |
+
self.f_a = Matrix(f_a)
|
67 |
+
|
68 |
+
# Generalized equation variables
|
69 |
+
self.q = Matrix(q)
|
70 |
+
self.u = Matrix(u)
|
71 |
+
none_handler = lambda x: Matrix(x) if x else Matrix()
|
72 |
+
self.q_i = none_handler(q_i)
|
73 |
+
self.q_d = none_handler(q_d)
|
74 |
+
self.u_i = none_handler(u_i)
|
75 |
+
self.u_d = none_handler(u_d)
|
76 |
+
self.r = none_handler(r)
|
77 |
+
self.lams = none_handler(lams)
|
78 |
+
|
79 |
+
# Derivatives of generalized equation variables
|
80 |
+
self._qd = self.q.diff(dynamicsymbols._t)
|
81 |
+
self._ud = self.u.diff(dynamicsymbols._t)
|
82 |
+
# If the user doesn't actually use generalized variables, and the
|
83 |
+
# qd and u vectors have any intersecting variables, this can cause
|
84 |
+
# problems. We'll fix this with some hackery, and Dummy variables
|
85 |
+
dup_vars = set(self._qd).intersection(self.u)
|
86 |
+
self._qd_dup = Matrix([var if var not in dup_vars else Dummy()
|
87 |
+
for var in self._qd])
|
88 |
+
|
89 |
+
# Derive dimesion terms
|
90 |
+
l = len(self.f_c)
|
91 |
+
m = len(self.f_v)
|
92 |
+
n = len(self.q)
|
93 |
+
o = len(self.u)
|
94 |
+
s = len(self.r)
|
95 |
+
k = len(self.lams)
|
96 |
+
dims = namedtuple('dims', ['l', 'm', 'n', 'o', 's', 'k'])
|
97 |
+
self._dims = dims(l, m, n, o, s, k)
|
98 |
+
|
99 |
+
self._Pq = None
|
100 |
+
self._Pqi = None
|
101 |
+
self._Pqd = None
|
102 |
+
self._Pu = None
|
103 |
+
self._Pui = None
|
104 |
+
self._Pud = None
|
105 |
+
self._C_0 = None
|
106 |
+
self._C_1 = None
|
107 |
+
self._C_2 = None
|
108 |
+
self.perm_mat = None
|
109 |
+
|
110 |
+
self._setup_done = False
|
111 |
+
|
112 |
+
def _setup(self):
|
113 |
+
# Calculations here only need to be run once. They are moved out of
|
114 |
+
# the __init__ method to increase the speed of Linearizer creation.
|
115 |
+
self._form_permutation_matrices()
|
116 |
+
self._form_block_matrices()
|
117 |
+
self._form_coefficient_matrices()
|
118 |
+
self._setup_done = True
|
119 |
+
|
120 |
+
def _form_permutation_matrices(self):
|
121 |
+
"""Form the permutation matrices Pq and Pu."""
|
122 |
+
|
123 |
+
# Extract dimension variables
|
124 |
+
l, m, n, o, s, k = self._dims
|
125 |
+
# Compute permutation matrices
|
126 |
+
if n != 0:
|
127 |
+
self._Pq = permutation_matrix(self.q, Matrix([self.q_i, self.q_d]))
|
128 |
+
if l > 0:
|
129 |
+
self._Pqi = self._Pq[:, :-l]
|
130 |
+
self._Pqd = self._Pq[:, -l:]
|
131 |
+
else:
|
132 |
+
self._Pqi = self._Pq
|
133 |
+
self._Pqd = Matrix()
|
134 |
+
if o != 0:
|
135 |
+
self._Pu = permutation_matrix(self.u, Matrix([self.u_i, self.u_d]))
|
136 |
+
if m > 0:
|
137 |
+
self._Pui = self._Pu[:, :-m]
|
138 |
+
self._Pud = self._Pu[:, -m:]
|
139 |
+
else:
|
140 |
+
self._Pui = self._Pu
|
141 |
+
self._Pud = Matrix()
|
142 |
+
# Compute combination permutation matrix for computing A and B
|
143 |
+
P_col1 = Matrix([self._Pqi, zeros(o + k, n - l)])
|
144 |
+
P_col2 = Matrix([zeros(n, o - m), self._Pui, zeros(k, o - m)])
|
145 |
+
if P_col1:
|
146 |
+
if P_col2:
|
147 |
+
self.perm_mat = P_col1.row_join(P_col2)
|
148 |
+
else:
|
149 |
+
self.perm_mat = P_col1
|
150 |
+
else:
|
151 |
+
self.perm_mat = P_col2
|
152 |
+
|
153 |
+
def _form_coefficient_matrices(self):
|
154 |
+
"""Form the coefficient matrices C_0, C_1, and C_2."""
|
155 |
+
|
156 |
+
# Extract dimension variables
|
157 |
+
l, m, n, o, s, k = self._dims
|
158 |
+
# Build up the coefficient matrices C_0, C_1, and C_2
|
159 |
+
# If there are configuration constraints (l > 0), form C_0 as normal.
|
160 |
+
# If not, C_0 is I_(nxn). Note that this works even if n=0
|
161 |
+
if l > 0:
|
162 |
+
f_c_jac_q = self.f_c.jacobian(self.q)
|
163 |
+
self._C_0 = (eye(n) - self._Pqd * (f_c_jac_q *
|
164 |
+
self._Pqd).LUsolve(f_c_jac_q)) * self._Pqi
|
165 |
+
else:
|
166 |
+
self._C_0 = eye(n)
|
167 |
+
# If there are motion constraints (m > 0), form C_1 and C_2 as normal.
|
168 |
+
# If not, C_1 is 0, and C_2 is I_(oxo). Note that this works even if
|
169 |
+
# o = 0.
|
170 |
+
if m > 0:
|
171 |
+
f_v_jac_u = self.f_v.jacobian(self.u)
|
172 |
+
temp = f_v_jac_u * self._Pud
|
173 |
+
if n != 0:
|
174 |
+
f_v_jac_q = self.f_v.jacobian(self.q)
|
175 |
+
self._C_1 = -self._Pud * temp.LUsolve(f_v_jac_q)
|
176 |
+
else:
|
177 |
+
self._C_1 = zeros(o, n)
|
178 |
+
self._C_2 = (eye(o) - self._Pud *
|
179 |
+
temp.LUsolve(f_v_jac_u)) * self._Pui
|
180 |
+
else:
|
181 |
+
self._C_1 = zeros(o, n)
|
182 |
+
self._C_2 = eye(o)
|
183 |
+
|
184 |
+
def _form_block_matrices(self):
|
185 |
+
"""Form the block matrices for composing M, A, and B."""
|
186 |
+
|
187 |
+
# Extract dimension variables
|
188 |
+
l, m, n, o, s, k = self._dims
|
189 |
+
# Block Matrix Definitions. These are only defined if under certain
|
190 |
+
# conditions. If undefined, an empty matrix is used instead
|
191 |
+
if n != 0:
|
192 |
+
self._M_qq = self.f_0.jacobian(self._qd)
|
193 |
+
self._A_qq = -(self.f_0 + self.f_1).jacobian(self.q)
|
194 |
+
else:
|
195 |
+
self._M_qq = Matrix()
|
196 |
+
self._A_qq = Matrix()
|
197 |
+
if n != 0 and m != 0:
|
198 |
+
self._M_uqc = self.f_a.jacobian(self._qd_dup)
|
199 |
+
self._A_uqc = -self.f_a.jacobian(self.q)
|
200 |
+
else:
|
201 |
+
self._M_uqc = Matrix()
|
202 |
+
self._A_uqc = Matrix()
|
203 |
+
if n != 0 and o - m + k != 0:
|
204 |
+
self._M_uqd = self.f_3.jacobian(self._qd_dup)
|
205 |
+
self._A_uqd = -(self.f_2 + self.f_3 + self.f_4).jacobian(self.q)
|
206 |
+
else:
|
207 |
+
self._M_uqd = Matrix()
|
208 |
+
self._A_uqd = Matrix()
|
209 |
+
if o != 0 and m != 0:
|
210 |
+
self._M_uuc = self.f_a.jacobian(self._ud)
|
211 |
+
self._A_uuc = -self.f_a.jacobian(self.u)
|
212 |
+
else:
|
213 |
+
self._M_uuc = Matrix()
|
214 |
+
self._A_uuc = Matrix()
|
215 |
+
if o != 0 and o - m + k != 0:
|
216 |
+
self._M_uud = self.f_2.jacobian(self._ud)
|
217 |
+
self._A_uud = -(self.f_2 + self.f_3).jacobian(self.u)
|
218 |
+
else:
|
219 |
+
self._M_uud = Matrix()
|
220 |
+
self._A_uud = Matrix()
|
221 |
+
if o != 0 and n != 0:
|
222 |
+
self._A_qu = -self.f_1.jacobian(self.u)
|
223 |
+
else:
|
224 |
+
self._A_qu = Matrix()
|
225 |
+
if k != 0 and o - m + k != 0:
|
226 |
+
self._M_uld = self.f_4.jacobian(self.lams)
|
227 |
+
else:
|
228 |
+
self._M_uld = Matrix()
|
229 |
+
if s != 0 and o - m + k != 0:
|
230 |
+
self._B_u = -self.f_3.jacobian(self.r)
|
231 |
+
else:
|
232 |
+
self._B_u = Matrix()
|
233 |
+
|
234 |
+
def linearize(self, op_point=None, A_and_B=False, simplify=False):
|
235 |
+
"""Linearize the system about the operating point. Note that
|
236 |
+
q_op, u_op, qd_op, ud_op must satisfy the equations of motion.
|
237 |
+
These may be either symbolic or numeric.
|
238 |
+
|
239 |
+
Parameters
|
240 |
+
==========
|
241 |
+
|
242 |
+
op_point : dict or iterable of dicts, optional
|
243 |
+
Dictionary or iterable of dictionaries containing the operating
|
244 |
+
point conditions. These will be substituted in to the linearized
|
245 |
+
system before the linearization is complete. Leave blank if you
|
246 |
+
want a completely symbolic form. Note that any reduction in
|
247 |
+
symbols (whether substituted for numbers or expressions with a
|
248 |
+
common parameter) will result in faster runtime.
|
249 |
+
|
250 |
+
A_and_B : bool, optional
|
251 |
+
If A_and_B=False (default), (M, A, B) is returned for forming
|
252 |
+
[M]*[q, u]^T = [A]*[q_ind, u_ind]^T + [B]r. If A_and_B=True,
|
253 |
+
(A, B) is returned for forming dx = [A]x + [B]r, where
|
254 |
+
x = [q_ind, u_ind]^T.
|
255 |
+
|
256 |
+
simplify : bool, optional
|
257 |
+
Determines if returned values are simplified before return.
|
258 |
+
For large expressions this may be time consuming. Default is False.
|
259 |
+
|
260 |
+
Potential Issues
|
261 |
+
================
|
262 |
+
|
263 |
+
Note that the process of solving with A_and_B=True is
|
264 |
+
computationally intensive if there are many symbolic parameters.
|
265 |
+
For this reason, it may be more desirable to use the default
|
266 |
+
A_and_B=False, returning M, A, and B. More values may then be
|
267 |
+
substituted in to these matrices later on. The state space form can
|
268 |
+
then be found as A = P.T*M.LUsolve(A), B = P.T*M.LUsolve(B), where
|
269 |
+
P = Linearizer.perm_mat.
|
270 |
+
"""
|
271 |
+
|
272 |
+
# Run the setup if needed:
|
273 |
+
if not self._setup_done:
|
274 |
+
self._setup()
|
275 |
+
|
276 |
+
# Compose dict of operating conditions
|
277 |
+
if isinstance(op_point, dict):
|
278 |
+
op_point_dict = op_point
|
279 |
+
elif isinstance(op_point, Iterable):
|
280 |
+
op_point_dict = {}
|
281 |
+
for op in op_point:
|
282 |
+
op_point_dict.update(op)
|
283 |
+
else:
|
284 |
+
op_point_dict = {}
|
285 |
+
|
286 |
+
# Extract dimension variables
|
287 |
+
l, m, n, o, s, k = self._dims
|
288 |
+
|
289 |
+
# Rename terms to shorten expressions
|
290 |
+
M_qq = self._M_qq
|
291 |
+
M_uqc = self._M_uqc
|
292 |
+
M_uqd = self._M_uqd
|
293 |
+
M_uuc = self._M_uuc
|
294 |
+
M_uud = self._M_uud
|
295 |
+
M_uld = self._M_uld
|
296 |
+
A_qq = self._A_qq
|
297 |
+
A_uqc = self._A_uqc
|
298 |
+
A_uqd = self._A_uqd
|
299 |
+
A_qu = self._A_qu
|
300 |
+
A_uuc = self._A_uuc
|
301 |
+
A_uud = self._A_uud
|
302 |
+
B_u = self._B_u
|
303 |
+
C_0 = self._C_0
|
304 |
+
C_1 = self._C_1
|
305 |
+
C_2 = self._C_2
|
306 |
+
|
307 |
+
# Build up Mass Matrix
|
308 |
+
# |M_qq 0_nxo 0_nxk|
|
309 |
+
# M = |M_uqc M_uuc 0_mxk|
|
310 |
+
# |M_uqd M_uud M_uld|
|
311 |
+
if o != 0:
|
312 |
+
col2 = Matrix([zeros(n, o), M_uuc, M_uud])
|
313 |
+
if k != 0:
|
314 |
+
col3 = Matrix([zeros(n + m, k), M_uld])
|
315 |
+
if n != 0:
|
316 |
+
col1 = Matrix([M_qq, M_uqc, M_uqd])
|
317 |
+
if o != 0 and k != 0:
|
318 |
+
M = col1.row_join(col2).row_join(col3)
|
319 |
+
elif o != 0:
|
320 |
+
M = col1.row_join(col2)
|
321 |
+
else:
|
322 |
+
M = col1
|
323 |
+
elif k != 0:
|
324 |
+
M = col2.row_join(col3)
|
325 |
+
else:
|
326 |
+
M = col2
|
327 |
+
M_eq = msubs(M, op_point_dict)
|
328 |
+
|
329 |
+
# Build up state coefficient matrix A
|
330 |
+
# |(A_qq + A_qu*C_1)*C_0 A_qu*C_2|
|
331 |
+
# A = |(A_uqc + A_uuc*C_1)*C_0 A_uuc*C_2|
|
332 |
+
# |(A_uqd + A_uud*C_1)*C_0 A_uud*C_2|
|
333 |
+
# Col 1 is only defined if n != 0
|
334 |
+
if n != 0:
|
335 |
+
r1c1 = A_qq
|
336 |
+
if o != 0:
|
337 |
+
r1c1 += (A_qu * C_1)
|
338 |
+
r1c1 = r1c1 * C_0
|
339 |
+
if m != 0:
|
340 |
+
r2c1 = A_uqc
|
341 |
+
if o != 0:
|
342 |
+
r2c1 += (A_uuc * C_1)
|
343 |
+
r2c1 = r2c1 * C_0
|
344 |
+
else:
|
345 |
+
r2c1 = Matrix()
|
346 |
+
if o - m + k != 0:
|
347 |
+
r3c1 = A_uqd
|
348 |
+
if o != 0:
|
349 |
+
r3c1 += (A_uud * C_1)
|
350 |
+
r3c1 = r3c1 * C_0
|
351 |
+
else:
|
352 |
+
r3c1 = Matrix()
|
353 |
+
col1 = Matrix([r1c1, r2c1, r3c1])
|
354 |
+
else:
|
355 |
+
col1 = Matrix()
|
356 |
+
# Col 2 is only defined if o != 0
|
357 |
+
if o != 0:
|
358 |
+
if n != 0:
|
359 |
+
r1c2 = A_qu * C_2
|
360 |
+
else:
|
361 |
+
r1c2 = Matrix()
|
362 |
+
if m != 0:
|
363 |
+
r2c2 = A_uuc * C_2
|
364 |
+
else:
|
365 |
+
r2c2 = Matrix()
|
366 |
+
if o - m + k != 0:
|
367 |
+
r3c2 = A_uud * C_2
|
368 |
+
else:
|
369 |
+
r3c2 = Matrix()
|
370 |
+
col2 = Matrix([r1c2, r2c2, r3c2])
|
371 |
+
else:
|
372 |
+
col2 = Matrix()
|
373 |
+
if col1:
|
374 |
+
if col2:
|
375 |
+
Amat = col1.row_join(col2)
|
376 |
+
else:
|
377 |
+
Amat = col1
|
378 |
+
else:
|
379 |
+
Amat = col2
|
380 |
+
Amat_eq = msubs(Amat, op_point_dict)
|
381 |
+
|
382 |
+
# Build up the B matrix if there are forcing variables
|
383 |
+
# |0_(n + m)xs|
|
384 |
+
# B = |B_u |
|
385 |
+
if s != 0 and o - m + k != 0:
|
386 |
+
Bmat = zeros(n + m, s).col_join(B_u)
|
387 |
+
Bmat_eq = msubs(Bmat, op_point_dict)
|
388 |
+
else:
|
389 |
+
Bmat_eq = Matrix()
|
390 |
+
|
391 |
+
# kwarg A_and_B indicates to return A, B for forming the equation
|
392 |
+
# dx = [A]x + [B]r, where x = [q_indnd, u_indnd]^T,
|
393 |
+
if A_and_B:
|
394 |
+
A_cont = self.perm_mat.T * M_eq.LUsolve(Amat_eq)
|
395 |
+
if Bmat_eq:
|
396 |
+
B_cont = self.perm_mat.T * M_eq.LUsolve(Bmat_eq)
|
397 |
+
else:
|
398 |
+
# Bmat = Matrix([]), so no need to sub
|
399 |
+
B_cont = Bmat_eq
|
400 |
+
if simplify:
|
401 |
+
A_cont.simplify()
|
402 |
+
B_cont.simplify()
|
403 |
+
return A_cont, B_cont
|
404 |
+
# Otherwise return M, A, B for forming the equation
|
405 |
+
# [M]dx = [A]x + [B]r, where x = [q, u]^T
|
406 |
+
else:
|
407 |
+
if simplify:
|
408 |
+
M_eq.simplify()
|
409 |
+
Amat_eq.simplify()
|
410 |
+
Bmat_eq.simplify()
|
411 |
+
return M_eq, Amat_eq, Bmat_eq
|
412 |
+
|
413 |
+
|
414 |
+
def permutation_matrix(orig_vec, per_vec):
|
415 |
+
"""Compute the permutation matrix to change order of
|
416 |
+
orig_vec into order of per_vec.
|
417 |
+
|
418 |
+
Parameters
|
419 |
+
==========
|
420 |
+
|
421 |
+
orig_vec : array_like
|
422 |
+
Symbols in original ordering.
|
423 |
+
per_vec : array_like
|
424 |
+
Symbols in new ordering.
|
425 |
+
|
426 |
+
Returns
|
427 |
+
=======
|
428 |
+
|
429 |
+
p_matrix : Matrix
|
430 |
+
Permutation matrix such that orig_vec == (p_matrix * per_vec).
|
431 |
+
"""
|
432 |
+
if not isinstance(orig_vec, (list, tuple)):
|
433 |
+
orig_vec = flatten(orig_vec)
|
434 |
+
if not isinstance(per_vec, (list, tuple)):
|
435 |
+
per_vec = flatten(per_vec)
|
436 |
+
if set(orig_vec) != set(per_vec):
|
437 |
+
raise ValueError("orig_vec and per_vec must be the same length, " +
|
438 |
+
"and contain the same symbols.")
|
439 |
+
ind_list = [orig_vec.index(i) for i in per_vec]
|
440 |
+
p_matrix = zeros(len(orig_vec))
|
441 |
+
for i, j in enumerate(ind_list):
|
442 |
+
p_matrix[i, j] = 1
|
443 |
+
return p_matrix
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/method.py
ADDED
@@ -0,0 +1,39 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from abc import ABC, abstractmethod
|
2 |
+
|
3 |
+
class _Methods(ABC):
|
4 |
+
"""Abstract Base Class for all methods."""
|
5 |
+
|
6 |
+
@abstractmethod
|
7 |
+
def q(self):
|
8 |
+
pass
|
9 |
+
|
10 |
+
@abstractmethod
|
11 |
+
def u(self):
|
12 |
+
pass
|
13 |
+
|
14 |
+
@abstractmethod
|
15 |
+
def bodies(self):
|
16 |
+
pass
|
17 |
+
|
18 |
+
@abstractmethod
|
19 |
+
def loads(self):
|
20 |
+
pass
|
21 |
+
|
22 |
+
@abstractmethod
|
23 |
+
def mass_matrix(self):
|
24 |
+
pass
|
25 |
+
|
26 |
+
@abstractmethod
|
27 |
+
def forcing(self):
|
28 |
+
pass
|
29 |
+
|
30 |
+
@abstractmethod
|
31 |
+
def mass_matrix_full(self):
|
32 |
+
pass
|
33 |
+
|
34 |
+
@abstractmethod
|
35 |
+
def forcing_full(self):
|
36 |
+
pass
|
37 |
+
|
38 |
+
def _form_eoms(self):
|
39 |
+
raise NotImplementedError("Subclasses must implement this.")
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/models.py
ADDED
@@ -0,0 +1,230 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
#!/usr/bin/env python
|
2 |
+
"""This module contains some sample symbolic models used for testing and
|
3 |
+
examples."""
|
4 |
+
|
5 |
+
# Internal imports
|
6 |
+
from sympy.core import backend as sm
|
7 |
+
import sympy.physics.mechanics as me
|
8 |
+
|
9 |
+
|
10 |
+
def multi_mass_spring_damper(n=1, apply_gravity=False,
|
11 |
+
apply_external_forces=False):
|
12 |
+
r"""Returns a system containing the symbolic equations of motion and
|
13 |
+
associated variables for a simple multi-degree of freedom point mass,
|
14 |
+
spring, damper system with optional gravitational and external
|
15 |
+
specified forces. For example, a two mass system under the influence of
|
16 |
+
gravity and external forces looks like:
|
17 |
+
|
18 |
+
::
|
19 |
+
|
20 |
+
----------------
|
21 |
+
| | | | g
|
22 |
+
\ | | | V
|
23 |
+
k0 / --- c0 |
|
24 |
+
| | | x0, v0
|
25 |
+
--------- V
|
26 |
+
| m0 | -----
|
27 |
+
--------- |
|
28 |
+
| | | |
|
29 |
+
\ v | | |
|
30 |
+
k1 / f0 --- c1 |
|
31 |
+
| | | x1, v1
|
32 |
+
--------- V
|
33 |
+
| m1 | -----
|
34 |
+
---------
|
35 |
+
| f1
|
36 |
+
V
|
37 |
+
|
38 |
+
Parameters
|
39 |
+
==========
|
40 |
+
|
41 |
+
n : integer
|
42 |
+
The number of masses in the serial chain.
|
43 |
+
apply_gravity : boolean
|
44 |
+
If true, gravity will be applied to each mass.
|
45 |
+
apply_external_forces : boolean
|
46 |
+
If true, a time varying external force will be applied to each mass.
|
47 |
+
|
48 |
+
Returns
|
49 |
+
=======
|
50 |
+
|
51 |
+
kane : sympy.physics.mechanics.kane.KanesMethod
|
52 |
+
A KanesMethod object.
|
53 |
+
|
54 |
+
"""
|
55 |
+
|
56 |
+
mass = sm.symbols('m:{}'.format(n))
|
57 |
+
stiffness = sm.symbols('k:{}'.format(n))
|
58 |
+
damping = sm.symbols('c:{}'.format(n))
|
59 |
+
|
60 |
+
acceleration_due_to_gravity = sm.symbols('g')
|
61 |
+
|
62 |
+
coordinates = me.dynamicsymbols('x:{}'.format(n))
|
63 |
+
speeds = me.dynamicsymbols('v:{}'.format(n))
|
64 |
+
specifieds = me.dynamicsymbols('f:{}'.format(n))
|
65 |
+
|
66 |
+
ceiling = me.ReferenceFrame('N')
|
67 |
+
origin = me.Point('origin')
|
68 |
+
origin.set_vel(ceiling, 0)
|
69 |
+
|
70 |
+
points = [origin]
|
71 |
+
kinematic_equations = []
|
72 |
+
particles = []
|
73 |
+
forces = []
|
74 |
+
|
75 |
+
for i in range(n):
|
76 |
+
|
77 |
+
center = points[-1].locatenew('center{}'.format(i),
|
78 |
+
coordinates[i] * ceiling.x)
|
79 |
+
center.set_vel(ceiling, points[-1].vel(ceiling) +
|
80 |
+
speeds[i] * ceiling.x)
|
81 |
+
points.append(center)
|
82 |
+
|
83 |
+
block = me.Particle('block{}'.format(i), center, mass[i])
|
84 |
+
|
85 |
+
kinematic_equations.append(speeds[i] - coordinates[i].diff())
|
86 |
+
|
87 |
+
total_force = (-stiffness[i] * coordinates[i] -
|
88 |
+
damping[i] * speeds[i])
|
89 |
+
try:
|
90 |
+
total_force += (stiffness[i + 1] * coordinates[i + 1] +
|
91 |
+
damping[i + 1] * speeds[i + 1])
|
92 |
+
except IndexError: # no force from below on last mass
|
93 |
+
pass
|
94 |
+
|
95 |
+
if apply_gravity:
|
96 |
+
total_force += mass[i] * acceleration_due_to_gravity
|
97 |
+
|
98 |
+
if apply_external_forces:
|
99 |
+
total_force += specifieds[i]
|
100 |
+
|
101 |
+
forces.append((center, total_force * ceiling.x))
|
102 |
+
|
103 |
+
particles.append(block)
|
104 |
+
|
105 |
+
kane = me.KanesMethod(ceiling, q_ind=coordinates, u_ind=speeds,
|
106 |
+
kd_eqs=kinematic_equations)
|
107 |
+
kane.kanes_equations(particles, forces)
|
108 |
+
|
109 |
+
return kane
|
110 |
+
|
111 |
+
|
112 |
+
def n_link_pendulum_on_cart(n=1, cart_force=True, joint_torques=False):
|
113 |
+
r"""Returns the system containing the symbolic first order equations of
|
114 |
+
motion for a 2D n-link pendulum on a sliding cart under the influence of
|
115 |
+
gravity.
|
116 |
+
|
117 |
+
::
|
118 |
+
|
119 |
+
|
|
120 |
+
o y v
|
121 |
+
\ 0 ^ g
|
122 |
+
\ |
|
123 |
+
--\-|----
|
124 |
+
| \| |
|
125 |
+
F-> | o --|---> x
|
126 |
+
| |
|
127 |
+
---------
|
128 |
+
o o
|
129 |
+
|
130 |
+
Parameters
|
131 |
+
==========
|
132 |
+
|
133 |
+
n : integer
|
134 |
+
The number of links in the pendulum.
|
135 |
+
cart_force : boolean, default=True
|
136 |
+
If true an external specified lateral force is applied to the cart.
|
137 |
+
joint_torques : boolean, default=False
|
138 |
+
If true joint torques will be added as specified inputs at each
|
139 |
+
joint.
|
140 |
+
|
141 |
+
Returns
|
142 |
+
=======
|
143 |
+
|
144 |
+
kane : sympy.physics.mechanics.kane.KanesMethod
|
145 |
+
A KanesMethod object.
|
146 |
+
|
147 |
+
Notes
|
148 |
+
=====
|
149 |
+
|
150 |
+
The degrees of freedom of the system are n + 1, i.e. one for each
|
151 |
+
pendulum link and one for the lateral motion of the cart.
|
152 |
+
|
153 |
+
M x' = F, where x = [u0, ..., un+1, q0, ..., qn+1]
|
154 |
+
|
155 |
+
The joint angles are all defined relative to the ground where the x axis
|
156 |
+
defines the ground line and the y axis points up. The joint torques are
|
157 |
+
applied between each adjacent link and the between the cart and the
|
158 |
+
lower link where a positive torque corresponds to positive angle.
|
159 |
+
|
160 |
+
"""
|
161 |
+
if n <= 0:
|
162 |
+
raise ValueError('The number of links must be a positive integer.')
|
163 |
+
|
164 |
+
q = me.dynamicsymbols('q:{}'.format(n + 1))
|
165 |
+
u = me.dynamicsymbols('u:{}'.format(n + 1))
|
166 |
+
|
167 |
+
if joint_torques is True:
|
168 |
+
T = me.dynamicsymbols('T1:{}'.format(n + 1))
|
169 |
+
|
170 |
+
m = sm.symbols('m:{}'.format(n + 1))
|
171 |
+
l = sm.symbols('l:{}'.format(n))
|
172 |
+
g, t = sm.symbols('g t')
|
173 |
+
|
174 |
+
I = me.ReferenceFrame('I')
|
175 |
+
O = me.Point('O')
|
176 |
+
O.set_vel(I, 0)
|
177 |
+
|
178 |
+
P0 = me.Point('P0')
|
179 |
+
P0.set_pos(O, q[0] * I.x)
|
180 |
+
P0.set_vel(I, u[0] * I.x)
|
181 |
+
Pa0 = me.Particle('Pa0', P0, m[0])
|
182 |
+
|
183 |
+
frames = [I]
|
184 |
+
points = [P0]
|
185 |
+
particles = [Pa0]
|
186 |
+
forces = [(P0, -m[0] * g * I.y)]
|
187 |
+
kindiffs = [q[0].diff(t) - u[0]]
|
188 |
+
|
189 |
+
if cart_force is True or joint_torques is True:
|
190 |
+
specified = []
|
191 |
+
else:
|
192 |
+
specified = None
|
193 |
+
|
194 |
+
for i in range(n):
|
195 |
+
Bi = I.orientnew('B{}'.format(i), 'Axis', [q[i + 1], I.z])
|
196 |
+
Bi.set_ang_vel(I, u[i + 1] * I.z)
|
197 |
+
frames.append(Bi)
|
198 |
+
|
199 |
+
Pi = points[-1].locatenew('P{}'.format(i + 1), l[i] * Bi.y)
|
200 |
+
Pi.v2pt_theory(points[-1], I, Bi)
|
201 |
+
points.append(Pi)
|
202 |
+
|
203 |
+
Pai = me.Particle('Pa' + str(i + 1), Pi, m[i + 1])
|
204 |
+
particles.append(Pai)
|
205 |
+
|
206 |
+
forces.append((Pi, -m[i + 1] * g * I.y))
|
207 |
+
|
208 |
+
if joint_torques is True:
|
209 |
+
|
210 |
+
specified.append(T[i])
|
211 |
+
|
212 |
+
if i == 0:
|
213 |
+
forces.append((I, -T[i] * I.z))
|
214 |
+
|
215 |
+
if i == n - 1:
|
216 |
+
forces.append((Bi, T[i] * I.z))
|
217 |
+
else:
|
218 |
+
forces.append((Bi, T[i] * I.z - T[i + 1] * I.z))
|
219 |
+
|
220 |
+
kindiffs.append(q[i + 1].diff(t) - u[i + 1])
|
221 |
+
|
222 |
+
if cart_force is True:
|
223 |
+
F = me.dynamicsymbols('F')
|
224 |
+
forces.append((P0, F * I.x))
|
225 |
+
specified.append(F)
|
226 |
+
|
227 |
+
kane = me.KanesMethod(I, q_ind=q, u_ind=u, kd_eqs=kindiffs)
|
228 |
+
kane.kanes_equations(particles, forces)
|
229 |
+
|
230 |
+
return kane
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/particle.py
ADDED
@@ -0,0 +1,281 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.core.backend import sympify
|
2 |
+
from sympy.physics.vector import Point
|
3 |
+
|
4 |
+
from sympy.utilities.exceptions import sympy_deprecation_warning
|
5 |
+
|
6 |
+
__all__ = ['Particle']
|
7 |
+
|
8 |
+
|
9 |
+
class Particle:
|
10 |
+
"""A particle.
|
11 |
+
|
12 |
+
Explanation
|
13 |
+
===========
|
14 |
+
|
15 |
+
Particles have a non-zero mass and lack spatial extension; they take up no
|
16 |
+
space.
|
17 |
+
|
18 |
+
Values need to be supplied on initialization, but can be changed later.
|
19 |
+
|
20 |
+
Parameters
|
21 |
+
==========
|
22 |
+
|
23 |
+
name : str
|
24 |
+
Name of particle
|
25 |
+
point : Point
|
26 |
+
A physics/mechanics Point which represents the position, velocity, and
|
27 |
+
acceleration of this Particle
|
28 |
+
mass : sympifyable
|
29 |
+
A SymPy expression representing the Particle's mass
|
30 |
+
|
31 |
+
Examples
|
32 |
+
========
|
33 |
+
|
34 |
+
>>> from sympy.physics.mechanics import Particle, Point
|
35 |
+
>>> from sympy import Symbol
|
36 |
+
>>> po = Point('po')
|
37 |
+
>>> m = Symbol('m')
|
38 |
+
>>> pa = Particle('pa', po, m)
|
39 |
+
>>> # Or you could change these later
|
40 |
+
>>> pa.mass = m
|
41 |
+
>>> pa.point = po
|
42 |
+
|
43 |
+
"""
|
44 |
+
|
45 |
+
def __init__(self, name, point, mass):
|
46 |
+
if not isinstance(name, str):
|
47 |
+
raise TypeError('Supply a valid name.')
|
48 |
+
self._name = name
|
49 |
+
self.mass = mass
|
50 |
+
self.point = point
|
51 |
+
self.potential_energy = 0
|
52 |
+
|
53 |
+
def __str__(self):
|
54 |
+
return self._name
|
55 |
+
|
56 |
+
def __repr__(self):
|
57 |
+
return self.__str__()
|
58 |
+
|
59 |
+
@property
|
60 |
+
def mass(self):
|
61 |
+
"""Mass of the particle."""
|
62 |
+
return self._mass
|
63 |
+
|
64 |
+
@mass.setter
|
65 |
+
def mass(self, value):
|
66 |
+
self._mass = sympify(value)
|
67 |
+
|
68 |
+
@property
|
69 |
+
def point(self):
|
70 |
+
"""Point of the particle."""
|
71 |
+
return self._point
|
72 |
+
|
73 |
+
@point.setter
|
74 |
+
def point(self, p):
|
75 |
+
if not isinstance(p, Point):
|
76 |
+
raise TypeError("Particle point attribute must be a Point object.")
|
77 |
+
self._point = p
|
78 |
+
|
79 |
+
def linear_momentum(self, frame):
|
80 |
+
"""Linear momentum of the particle.
|
81 |
+
|
82 |
+
Explanation
|
83 |
+
===========
|
84 |
+
|
85 |
+
The linear momentum L, of a particle P, with respect to frame N is
|
86 |
+
given by:
|
87 |
+
|
88 |
+
L = m * v
|
89 |
+
|
90 |
+
where m is the mass of the particle, and v is the velocity of the
|
91 |
+
particle in the frame N.
|
92 |
+
|
93 |
+
Parameters
|
94 |
+
==========
|
95 |
+
|
96 |
+
frame : ReferenceFrame
|
97 |
+
The frame in which linear momentum is desired.
|
98 |
+
|
99 |
+
Examples
|
100 |
+
========
|
101 |
+
|
102 |
+
>>> from sympy.physics.mechanics import Particle, Point, ReferenceFrame
|
103 |
+
>>> from sympy.physics.mechanics import dynamicsymbols
|
104 |
+
>>> from sympy.physics.vector import init_vprinting
|
105 |
+
>>> init_vprinting(pretty_print=False)
|
106 |
+
>>> m, v = dynamicsymbols('m v')
|
107 |
+
>>> N = ReferenceFrame('N')
|
108 |
+
>>> P = Point('P')
|
109 |
+
>>> A = Particle('A', P, m)
|
110 |
+
>>> P.set_vel(N, v * N.x)
|
111 |
+
>>> A.linear_momentum(N)
|
112 |
+
m*v*N.x
|
113 |
+
|
114 |
+
"""
|
115 |
+
|
116 |
+
return self.mass * self.point.vel(frame)
|
117 |
+
|
118 |
+
def angular_momentum(self, point, frame):
|
119 |
+
"""Angular momentum of the particle about the point.
|
120 |
+
|
121 |
+
Explanation
|
122 |
+
===========
|
123 |
+
|
124 |
+
The angular momentum H, about some point O of a particle, P, is given
|
125 |
+
by:
|
126 |
+
|
127 |
+
``H = cross(r, m * v)``
|
128 |
+
|
129 |
+
where r is the position vector from point O to the particle P, m is
|
130 |
+
the mass of the particle, and v is the velocity of the particle in
|
131 |
+
the inertial frame, N.
|
132 |
+
|
133 |
+
Parameters
|
134 |
+
==========
|
135 |
+
|
136 |
+
point : Point
|
137 |
+
The point about which angular momentum of the particle is desired.
|
138 |
+
|
139 |
+
frame : ReferenceFrame
|
140 |
+
The frame in which angular momentum is desired.
|
141 |
+
|
142 |
+
Examples
|
143 |
+
========
|
144 |
+
|
145 |
+
>>> from sympy.physics.mechanics import Particle, Point, ReferenceFrame
|
146 |
+
>>> from sympy.physics.mechanics import dynamicsymbols
|
147 |
+
>>> from sympy.physics.vector import init_vprinting
|
148 |
+
>>> init_vprinting(pretty_print=False)
|
149 |
+
>>> m, v, r = dynamicsymbols('m v r')
|
150 |
+
>>> N = ReferenceFrame('N')
|
151 |
+
>>> O = Point('O')
|
152 |
+
>>> A = O.locatenew('A', r * N.x)
|
153 |
+
>>> P = Particle('P', A, m)
|
154 |
+
>>> P.point.set_vel(N, v * N.y)
|
155 |
+
>>> P.angular_momentum(O, N)
|
156 |
+
m*r*v*N.z
|
157 |
+
|
158 |
+
"""
|
159 |
+
|
160 |
+
return self.point.pos_from(point) ^ (self.mass * self.point.vel(frame))
|
161 |
+
|
162 |
+
def kinetic_energy(self, frame):
|
163 |
+
"""Kinetic energy of the particle.
|
164 |
+
|
165 |
+
Explanation
|
166 |
+
===========
|
167 |
+
|
168 |
+
The kinetic energy, T, of a particle, P, is given by:
|
169 |
+
|
170 |
+
``T = 1/2 (dot(m * v, v))``
|
171 |
+
|
172 |
+
where m is the mass of particle P, and v is the velocity of the
|
173 |
+
particle in the supplied ReferenceFrame.
|
174 |
+
|
175 |
+
Parameters
|
176 |
+
==========
|
177 |
+
|
178 |
+
frame : ReferenceFrame
|
179 |
+
The Particle's velocity is typically defined with respect to
|
180 |
+
an inertial frame but any relevant frame in which the velocity is
|
181 |
+
known can be supplied.
|
182 |
+
|
183 |
+
Examples
|
184 |
+
========
|
185 |
+
|
186 |
+
>>> from sympy.physics.mechanics import Particle, Point, ReferenceFrame
|
187 |
+
>>> from sympy import symbols
|
188 |
+
>>> m, v, r = symbols('m v r')
|
189 |
+
>>> N = ReferenceFrame('N')
|
190 |
+
>>> O = Point('O')
|
191 |
+
>>> P = Particle('P', O, m)
|
192 |
+
>>> P.point.set_vel(N, v * N.y)
|
193 |
+
>>> P.kinetic_energy(N)
|
194 |
+
m*v**2/2
|
195 |
+
|
196 |
+
"""
|
197 |
+
|
198 |
+
return (self.mass / sympify(2) * self.point.vel(frame) &
|
199 |
+
self.point.vel(frame))
|
200 |
+
|
201 |
+
@property
|
202 |
+
def potential_energy(self):
|
203 |
+
"""The potential energy of the Particle.
|
204 |
+
|
205 |
+
Examples
|
206 |
+
========
|
207 |
+
|
208 |
+
>>> from sympy.physics.mechanics import Particle, Point
|
209 |
+
>>> from sympy import symbols
|
210 |
+
>>> m, g, h = symbols('m g h')
|
211 |
+
>>> O = Point('O')
|
212 |
+
>>> P = Particle('P', O, m)
|
213 |
+
>>> P.potential_energy = m * g * h
|
214 |
+
>>> P.potential_energy
|
215 |
+
g*h*m
|
216 |
+
|
217 |
+
"""
|
218 |
+
|
219 |
+
return self._pe
|
220 |
+
|
221 |
+
@potential_energy.setter
|
222 |
+
def potential_energy(self, scalar):
|
223 |
+
"""Used to set the potential energy of the Particle.
|
224 |
+
|
225 |
+
Parameters
|
226 |
+
==========
|
227 |
+
|
228 |
+
scalar : Sympifyable
|
229 |
+
The potential energy (a scalar) of the Particle.
|
230 |
+
|
231 |
+
Examples
|
232 |
+
========
|
233 |
+
|
234 |
+
>>> from sympy.physics.mechanics import Particle, Point
|
235 |
+
>>> from sympy import symbols
|
236 |
+
>>> m, g, h = symbols('m g h')
|
237 |
+
>>> O = Point('O')
|
238 |
+
>>> P = Particle('P', O, m)
|
239 |
+
>>> P.potential_energy = m * g * h
|
240 |
+
|
241 |
+
"""
|
242 |
+
|
243 |
+
self._pe = sympify(scalar)
|
244 |
+
|
245 |
+
def set_potential_energy(self, scalar):
|
246 |
+
sympy_deprecation_warning(
|
247 |
+
"""
|
248 |
+
The sympy.physics.mechanics.Particle.set_potential_energy()
|
249 |
+
method is deprecated. Instead use
|
250 |
+
|
251 |
+
P.potential_energy = scalar
|
252 |
+
""",
|
253 |
+
deprecated_since_version="1.5",
|
254 |
+
active_deprecations_target="deprecated-set-potential-energy",
|
255 |
+
)
|
256 |
+
self.potential_energy = scalar
|
257 |
+
|
258 |
+
def parallel_axis(self, point, frame):
|
259 |
+
"""Returns an inertia dyadic of the particle with respect to another
|
260 |
+
point and frame.
|
261 |
+
|
262 |
+
Parameters
|
263 |
+
==========
|
264 |
+
|
265 |
+
point : sympy.physics.vector.Point
|
266 |
+
The point to express the inertia dyadic about.
|
267 |
+
frame : sympy.physics.vector.ReferenceFrame
|
268 |
+
The reference frame used to construct the dyadic.
|
269 |
+
|
270 |
+
Returns
|
271 |
+
=======
|
272 |
+
|
273 |
+
inertia : sympy.physics.vector.Dyadic
|
274 |
+
The inertia dyadic of the particle expressed about the provided
|
275 |
+
point and frame.
|
276 |
+
|
277 |
+
"""
|
278 |
+
# circular import issue
|
279 |
+
from sympy.physics.mechanics import inertia_of_point_mass
|
280 |
+
return inertia_of_point_mass(self.mass, self.point.pos_from(point),
|
281 |
+
frame)
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/rigidbody.py
ADDED
@@ -0,0 +1,366 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.core.backend import sympify
|
2 |
+
from sympy.physics.vector import Point, ReferenceFrame, Dyadic
|
3 |
+
|
4 |
+
from sympy.utilities.exceptions import sympy_deprecation_warning
|
5 |
+
|
6 |
+
__all__ = ['RigidBody']
|
7 |
+
|
8 |
+
|
9 |
+
class RigidBody:
|
10 |
+
"""An idealized rigid body.
|
11 |
+
|
12 |
+
Explanation
|
13 |
+
===========
|
14 |
+
|
15 |
+
This is essentially a container which holds the various components which
|
16 |
+
describe a rigid body: a name, mass, center of mass, reference frame, and
|
17 |
+
inertia.
|
18 |
+
|
19 |
+
All of these need to be supplied on creation, but can be changed
|
20 |
+
afterwards.
|
21 |
+
|
22 |
+
Attributes
|
23 |
+
==========
|
24 |
+
|
25 |
+
name : string
|
26 |
+
The body's name.
|
27 |
+
masscenter : Point
|
28 |
+
The point which represents the center of mass of the rigid body.
|
29 |
+
frame : ReferenceFrame
|
30 |
+
The ReferenceFrame which the rigid body is fixed in.
|
31 |
+
mass : Sympifyable
|
32 |
+
The body's mass.
|
33 |
+
inertia : (Dyadic, Point)
|
34 |
+
The body's inertia about a point; stored in a tuple as shown above.
|
35 |
+
|
36 |
+
Examples
|
37 |
+
========
|
38 |
+
|
39 |
+
>>> from sympy import Symbol
|
40 |
+
>>> from sympy.physics.mechanics import ReferenceFrame, Point, RigidBody
|
41 |
+
>>> from sympy.physics.mechanics import outer
|
42 |
+
>>> m = Symbol('m')
|
43 |
+
>>> A = ReferenceFrame('A')
|
44 |
+
>>> P = Point('P')
|
45 |
+
>>> I = outer (A.x, A.x)
|
46 |
+
>>> inertia_tuple = (I, P)
|
47 |
+
>>> B = RigidBody('B', P, A, m, inertia_tuple)
|
48 |
+
>>> # Or you could change them afterwards
|
49 |
+
>>> m2 = Symbol('m2')
|
50 |
+
>>> B.mass = m2
|
51 |
+
|
52 |
+
"""
|
53 |
+
|
54 |
+
def __init__(self, name, masscenter, frame, mass, inertia):
|
55 |
+
if not isinstance(name, str):
|
56 |
+
raise TypeError('Supply a valid name.')
|
57 |
+
self._name = name
|
58 |
+
self.masscenter = masscenter
|
59 |
+
self.mass = mass
|
60 |
+
self.frame = frame
|
61 |
+
self.inertia = inertia
|
62 |
+
self.potential_energy = 0
|
63 |
+
|
64 |
+
def __str__(self):
|
65 |
+
return self._name
|
66 |
+
|
67 |
+
def __repr__(self):
|
68 |
+
return self.__str__()
|
69 |
+
|
70 |
+
@property
|
71 |
+
def frame(self):
|
72 |
+
"""The ReferenceFrame fixed to the body."""
|
73 |
+
return self._frame
|
74 |
+
|
75 |
+
@frame.setter
|
76 |
+
def frame(self, F):
|
77 |
+
if not isinstance(F, ReferenceFrame):
|
78 |
+
raise TypeError("RigidBody frame must be a ReferenceFrame object.")
|
79 |
+
self._frame = F
|
80 |
+
|
81 |
+
@property
|
82 |
+
def masscenter(self):
|
83 |
+
"""The body's center of mass."""
|
84 |
+
return self._masscenter
|
85 |
+
|
86 |
+
@masscenter.setter
|
87 |
+
def masscenter(self, p):
|
88 |
+
if not isinstance(p, Point):
|
89 |
+
raise TypeError("RigidBody center of mass must be a Point object.")
|
90 |
+
self._masscenter = p
|
91 |
+
|
92 |
+
@property
|
93 |
+
def mass(self):
|
94 |
+
"""The body's mass."""
|
95 |
+
return self._mass
|
96 |
+
|
97 |
+
@mass.setter
|
98 |
+
def mass(self, m):
|
99 |
+
self._mass = sympify(m)
|
100 |
+
|
101 |
+
@property
|
102 |
+
def inertia(self):
|
103 |
+
"""The body's inertia about a point; stored as (Dyadic, Point)."""
|
104 |
+
return (self._inertia, self._inertia_point)
|
105 |
+
|
106 |
+
@inertia.setter
|
107 |
+
def inertia(self, I):
|
108 |
+
if not isinstance(I[0], Dyadic):
|
109 |
+
raise TypeError("RigidBody inertia must be a Dyadic object.")
|
110 |
+
if not isinstance(I[1], Point):
|
111 |
+
raise TypeError("RigidBody inertia must be about a Point.")
|
112 |
+
self._inertia = I[0]
|
113 |
+
self._inertia_point = I[1]
|
114 |
+
# have I S/O, want I S/S*
|
115 |
+
# I S/O = I S/S* + I S*/O; I S/S* = I S/O - I S*/O
|
116 |
+
# I_S/S* = I_S/O - I_S*/O
|
117 |
+
from sympy.physics.mechanics.functions import inertia_of_point_mass
|
118 |
+
I_Ss_O = inertia_of_point_mass(self.mass,
|
119 |
+
self.masscenter.pos_from(I[1]),
|
120 |
+
self.frame)
|
121 |
+
self._central_inertia = I[0] - I_Ss_O
|
122 |
+
|
123 |
+
@property
|
124 |
+
def central_inertia(self):
|
125 |
+
"""The body's central inertia dyadic."""
|
126 |
+
return self._central_inertia
|
127 |
+
|
128 |
+
@central_inertia.setter
|
129 |
+
def central_inertia(self, I):
|
130 |
+
if not isinstance(I, Dyadic):
|
131 |
+
raise TypeError("RigidBody inertia must be a Dyadic object.")
|
132 |
+
self.inertia = (I, self.masscenter)
|
133 |
+
|
134 |
+
def linear_momentum(self, frame):
|
135 |
+
""" Linear momentum of the rigid body.
|
136 |
+
|
137 |
+
Explanation
|
138 |
+
===========
|
139 |
+
|
140 |
+
The linear momentum L, of a rigid body B, with respect to frame N is
|
141 |
+
given by:
|
142 |
+
|
143 |
+
L = M * v*
|
144 |
+
|
145 |
+
where M is the mass of the rigid body and v* is the velocity of
|
146 |
+
the mass center of B in the frame, N.
|
147 |
+
|
148 |
+
Parameters
|
149 |
+
==========
|
150 |
+
|
151 |
+
frame : ReferenceFrame
|
152 |
+
The frame in which linear momentum is desired.
|
153 |
+
|
154 |
+
Examples
|
155 |
+
========
|
156 |
+
|
157 |
+
>>> from sympy.physics.mechanics import Point, ReferenceFrame, outer
|
158 |
+
>>> from sympy.physics.mechanics import RigidBody, dynamicsymbols
|
159 |
+
>>> from sympy.physics.vector import init_vprinting
|
160 |
+
>>> init_vprinting(pretty_print=False)
|
161 |
+
>>> M, v = dynamicsymbols('M v')
|
162 |
+
>>> N = ReferenceFrame('N')
|
163 |
+
>>> P = Point('P')
|
164 |
+
>>> P.set_vel(N, v * N.x)
|
165 |
+
>>> I = outer (N.x, N.x)
|
166 |
+
>>> Inertia_tuple = (I, P)
|
167 |
+
>>> B = RigidBody('B', P, N, M, Inertia_tuple)
|
168 |
+
>>> B.linear_momentum(N)
|
169 |
+
M*v*N.x
|
170 |
+
|
171 |
+
"""
|
172 |
+
|
173 |
+
return self.mass * self.masscenter.vel(frame)
|
174 |
+
|
175 |
+
def angular_momentum(self, point, frame):
|
176 |
+
"""Returns the angular momentum of the rigid body about a point in the
|
177 |
+
given frame.
|
178 |
+
|
179 |
+
Explanation
|
180 |
+
===========
|
181 |
+
|
182 |
+
The angular momentum H of a rigid body B about some point O in a frame
|
183 |
+
N is given by:
|
184 |
+
|
185 |
+
``H = dot(I, w) + cross(r, M * v)``
|
186 |
+
|
187 |
+
where I is the central inertia dyadic of B, w is the angular velocity
|
188 |
+
of body B in the frame, N, r is the position vector from point O to the
|
189 |
+
mass center of B, and v is the velocity of the mass center in the
|
190 |
+
frame, N.
|
191 |
+
|
192 |
+
Parameters
|
193 |
+
==========
|
194 |
+
|
195 |
+
point : Point
|
196 |
+
The point about which angular momentum is desired.
|
197 |
+
frame : ReferenceFrame
|
198 |
+
The frame in which angular momentum is desired.
|
199 |
+
|
200 |
+
Examples
|
201 |
+
========
|
202 |
+
|
203 |
+
>>> from sympy.physics.mechanics import Point, ReferenceFrame, outer
|
204 |
+
>>> from sympy.physics.mechanics import RigidBody, dynamicsymbols
|
205 |
+
>>> from sympy.physics.vector import init_vprinting
|
206 |
+
>>> init_vprinting(pretty_print=False)
|
207 |
+
>>> M, v, r, omega = dynamicsymbols('M v r omega')
|
208 |
+
>>> N = ReferenceFrame('N')
|
209 |
+
>>> b = ReferenceFrame('b')
|
210 |
+
>>> b.set_ang_vel(N, omega * b.x)
|
211 |
+
>>> P = Point('P')
|
212 |
+
>>> P.set_vel(N, 1 * N.x)
|
213 |
+
>>> I = outer(b.x, b.x)
|
214 |
+
>>> B = RigidBody('B', P, b, M, (I, P))
|
215 |
+
>>> B.angular_momentum(P, N)
|
216 |
+
omega*b.x
|
217 |
+
|
218 |
+
"""
|
219 |
+
I = self.central_inertia
|
220 |
+
w = self.frame.ang_vel_in(frame)
|
221 |
+
m = self.mass
|
222 |
+
r = self.masscenter.pos_from(point)
|
223 |
+
v = self.masscenter.vel(frame)
|
224 |
+
|
225 |
+
return I.dot(w) + r.cross(m * v)
|
226 |
+
|
227 |
+
def kinetic_energy(self, frame):
|
228 |
+
"""Kinetic energy of the rigid body.
|
229 |
+
|
230 |
+
Explanation
|
231 |
+
===========
|
232 |
+
|
233 |
+
The kinetic energy, T, of a rigid body, B, is given by:
|
234 |
+
|
235 |
+
``T = 1/2 * (dot(dot(I, w), w) + dot(m * v, v))``
|
236 |
+
|
237 |
+
where I and m are the central inertia dyadic and mass of rigid body B,
|
238 |
+
respectively, omega is the body's angular velocity and v is the
|
239 |
+
velocity of the body's mass center in the supplied ReferenceFrame.
|
240 |
+
|
241 |
+
Parameters
|
242 |
+
==========
|
243 |
+
|
244 |
+
frame : ReferenceFrame
|
245 |
+
The RigidBody's angular velocity and the velocity of it's mass
|
246 |
+
center are typically defined with respect to an inertial frame but
|
247 |
+
any relevant frame in which the velocities are known can be supplied.
|
248 |
+
|
249 |
+
Examples
|
250 |
+
========
|
251 |
+
|
252 |
+
>>> from sympy.physics.mechanics import Point, ReferenceFrame, outer
|
253 |
+
>>> from sympy.physics.mechanics import RigidBody
|
254 |
+
>>> from sympy import symbols
|
255 |
+
>>> M, v, r, omega = symbols('M v r omega')
|
256 |
+
>>> N = ReferenceFrame('N')
|
257 |
+
>>> b = ReferenceFrame('b')
|
258 |
+
>>> b.set_ang_vel(N, omega * b.x)
|
259 |
+
>>> P = Point('P')
|
260 |
+
>>> P.set_vel(N, v * N.x)
|
261 |
+
>>> I = outer (b.x, b.x)
|
262 |
+
>>> inertia_tuple = (I, P)
|
263 |
+
>>> B = RigidBody('B', P, b, M, inertia_tuple)
|
264 |
+
>>> B.kinetic_energy(N)
|
265 |
+
M*v**2/2 + omega**2/2
|
266 |
+
|
267 |
+
"""
|
268 |
+
|
269 |
+
rotational_KE = (self.frame.ang_vel_in(frame) & (self.central_inertia &
|
270 |
+
self.frame.ang_vel_in(frame)) / sympify(2))
|
271 |
+
|
272 |
+
translational_KE = (self.mass * (self.masscenter.vel(frame) &
|
273 |
+
self.masscenter.vel(frame)) / sympify(2))
|
274 |
+
|
275 |
+
return rotational_KE + translational_KE
|
276 |
+
|
277 |
+
@property
|
278 |
+
def potential_energy(self):
|
279 |
+
"""The potential energy of the RigidBody.
|
280 |
+
|
281 |
+
Examples
|
282 |
+
========
|
283 |
+
|
284 |
+
>>> from sympy.physics.mechanics import RigidBody, Point, outer, ReferenceFrame
|
285 |
+
>>> from sympy import symbols
|
286 |
+
>>> M, g, h = symbols('M g h')
|
287 |
+
>>> b = ReferenceFrame('b')
|
288 |
+
>>> P = Point('P')
|
289 |
+
>>> I = outer (b.x, b.x)
|
290 |
+
>>> Inertia_tuple = (I, P)
|
291 |
+
>>> B = RigidBody('B', P, b, M, Inertia_tuple)
|
292 |
+
>>> B.potential_energy = M * g * h
|
293 |
+
>>> B.potential_energy
|
294 |
+
M*g*h
|
295 |
+
|
296 |
+
"""
|
297 |
+
|
298 |
+
return self._pe
|
299 |
+
|
300 |
+
@potential_energy.setter
|
301 |
+
def potential_energy(self, scalar):
|
302 |
+
"""Used to set the potential energy of this RigidBody.
|
303 |
+
|
304 |
+
Parameters
|
305 |
+
==========
|
306 |
+
|
307 |
+
scalar: Sympifyable
|
308 |
+
The potential energy (a scalar) of the RigidBody.
|
309 |
+
|
310 |
+
Examples
|
311 |
+
========
|
312 |
+
|
313 |
+
>>> from sympy.physics.mechanics import Point, outer
|
314 |
+
>>> from sympy.physics.mechanics import RigidBody, ReferenceFrame
|
315 |
+
>>> from sympy import symbols
|
316 |
+
>>> b = ReferenceFrame('b')
|
317 |
+
>>> M, g, h = symbols('M g h')
|
318 |
+
>>> P = Point('P')
|
319 |
+
>>> I = outer (b.x, b.x)
|
320 |
+
>>> Inertia_tuple = (I, P)
|
321 |
+
>>> B = RigidBody('B', P, b, M, Inertia_tuple)
|
322 |
+
>>> B.potential_energy = M * g * h
|
323 |
+
|
324 |
+
"""
|
325 |
+
|
326 |
+
self._pe = sympify(scalar)
|
327 |
+
|
328 |
+
def set_potential_energy(self, scalar):
|
329 |
+
sympy_deprecation_warning(
|
330 |
+
"""
|
331 |
+
The sympy.physics.mechanics.RigidBody.set_potential_energy()
|
332 |
+
method is deprecated. Instead use
|
333 |
+
|
334 |
+
B.potential_energy = scalar
|
335 |
+
""",
|
336 |
+
deprecated_since_version="1.5",
|
337 |
+
active_deprecations_target="deprecated-set-potential-energy",
|
338 |
+
)
|
339 |
+
self.potential_energy = scalar
|
340 |
+
|
341 |
+
def parallel_axis(self, point, frame=None):
|
342 |
+
"""Returns the inertia dyadic of the body with respect to another
|
343 |
+
point.
|
344 |
+
|
345 |
+
Parameters
|
346 |
+
==========
|
347 |
+
|
348 |
+
point : sympy.physics.vector.Point
|
349 |
+
The point to express the inertia dyadic about.
|
350 |
+
frame : sympy.physics.vector.ReferenceFrame
|
351 |
+
The reference frame used to construct the dyadic.
|
352 |
+
|
353 |
+
Returns
|
354 |
+
=======
|
355 |
+
|
356 |
+
inertia : sympy.physics.vector.Dyadic
|
357 |
+
The inertia dyadic of the rigid body expressed about the provided
|
358 |
+
point.
|
359 |
+
|
360 |
+
"""
|
361 |
+
# circular import issue
|
362 |
+
from sympy.physics.mechanics.functions import inertia_of_point_mass
|
363 |
+
if frame is None:
|
364 |
+
frame = self.frame
|
365 |
+
return self.central_inertia + inertia_of_point_mass(
|
366 |
+
self.mass, self.masscenter.pos_from(point), frame)
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/system.py
ADDED
@@ -0,0 +1,445 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.core.backend import eye, Matrix, zeros
|
2 |
+
from sympy.physics.mechanics import dynamicsymbols
|
3 |
+
from sympy.physics.mechanics.functions import find_dynamicsymbols
|
4 |
+
|
5 |
+
__all__ = ['SymbolicSystem']
|
6 |
+
|
7 |
+
|
8 |
+
class SymbolicSystem:
|
9 |
+
"""SymbolicSystem is a class that contains all the information about a
|
10 |
+
system in a symbolic format such as the equations of motions and the bodies
|
11 |
+
and loads in the system.
|
12 |
+
|
13 |
+
There are three ways that the equations of motion can be described for
|
14 |
+
Symbolic System:
|
15 |
+
|
16 |
+
|
17 |
+
[1] Explicit form where the kinematics and dynamics are combined
|
18 |
+
x' = F_1(x, t, r, p)
|
19 |
+
|
20 |
+
[2] Implicit form where the kinematics and dynamics are combined
|
21 |
+
M_2(x, p) x' = F_2(x, t, r, p)
|
22 |
+
|
23 |
+
[3] Implicit form where the kinematics and dynamics are separate
|
24 |
+
M_3(q, p) u' = F_3(q, u, t, r, p)
|
25 |
+
q' = G(q, u, t, r, p)
|
26 |
+
|
27 |
+
where
|
28 |
+
|
29 |
+
x : states, e.g. [q, u]
|
30 |
+
t : time
|
31 |
+
r : specified (exogenous) inputs
|
32 |
+
p : constants
|
33 |
+
q : generalized coordinates
|
34 |
+
u : generalized speeds
|
35 |
+
F_1 : right hand side of the combined equations in explicit form
|
36 |
+
F_2 : right hand side of the combined equations in implicit form
|
37 |
+
F_3 : right hand side of the dynamical equations in implicit form
|
38 |
+
M_2 : mass matrix of the combined equations in implicit form
|
39 |
+
M_3 : mass matrix of the dynamical equations in implicit form
|
40 |
+
G : right hand side of the kinematical differential equations
|
41 |
+
|
42 |
+
Parameters
|
43 |
+
==========
|
44 |
+
|
45 |
+
coord_states : ordered iterable of functions of time
|
46 |
+
This input will either be a collection of the coordinates or states
|
47 |
+
of the system depending on whether or not the speeds are also
|
48 |
+
given. If speeds are specified this input will be assumed to
|
49 |
+
be the coordinates otherwise this input will be assumed to
|
50 |
+
be the states.
|
51 |
+
|
52 |
+
right_hand_side : Matrix
|
53 |
+
This variable is the right hand side of the equations of motion in
|
54 |
+
any of the forms. The specific form will be assumed depending on
|
55 |
+
whether a mass matrix or coordinate derivatives are given.
|
56 |
+
|
57 |
+
speeds : ordered iterable of functions of time, optional
|
58 |
+
This is a collection of the generalized speeds of the system. If
|
59 |
+
given it will be assumed that the first argument (coord_states)
|
60 |
+
will represent the generalized coordinates of the system.
|
61 |
+
|
62 |
+
mass_matrix : Matrix, optional
|
63 |
+
The matrix of the implicit forms of the equations of motion (forms
|
64 |
+
[2] and [3]). The distinction between the forms is determined by
|
65 |
+
whether or not the coordinate derivatives are passed in. If
|
66 |
+
they are given form [3] will be assumed otherwise form [2] is
|
67 |
+
assumed.
|
68 |
+
|
69 |
+
coordinate_derivatives : Matrix, optional
|
70 |
+
The right hand side of the kinematical equations in explicit form.
|
71 |
+
If given it will be assumed that the equations of motion are being
|
72 |
+
entered in form [3].
|
73 |
+
|
74 |
+
alg_con : Iterable, optional
|
75 |
+
The indexes of the rows in the equations of motion that contain
|
76 |
+
algebraic constraints instead of differential equations. If the
|
77 |
+
equations are input in form [3], it will be assumed the indexes are
|
78 |
+
referencing the mass_matrix/right_hand_side combination and not the
|
79 |
+
coordinate_derivatives.
|
80 |
+
|
81 |
+
output_eqns : Dictionary, optional
|
82 |
+
Any output equations that are desired to be tracked are stored in a
|
83 |
+
dictionary where the key corresponds to the name given for the
|
84 |
+
specific equation and the value is the equation itself in symbolic
|
85 |
+
form
|
86 |
+
|
87 |
+
coord_idxs : Iterable, optional
|
88 |
+
If coord_states corresponds to the states rather than the
|
89 |
+
coordinates this variable will tell SymbolicSystem which indexes of
|
90 |
+
the states correspond to generalized coordinates.
|
91 |
+
|
92 |
+
speed_idxs : Iterable, optional
|
93 |
+
If coord_states corresponds to the states rather than the
|
94 |
+
coordinates this variable will tell SymbolicSystem which indexes of
|
95 |
+
the states correspond to generalized speeds.
|
96 |
+
|
97 |
+
bodies : iterable of Body/Rigidbody objects, optional
|
98 |
+
Iterable containing the bodies of the system
|
99 |
+
|
100 |
+
loads : iterable of load instances (described below), optional
|
101 |
+
Iterable containing the loads of the system where forces are given
|
102 |
+
by (point of application, force vector) and torques are given by
|
103 |
+
(reference frame acting upon, torque vector). Ex [(point, force),
|
104 |
+
(ref_frame, torque)]
|
105 |
+
|
106 |
+
Attributes
|
107 |
+
==========
|
108 |
+
|
109 |
+
coordinates : Matrix, shape(n, 1)
|
110 |
+
This is a matrix containing the generalized coordinates of the system
|
111 |
+
|
112 |
+
speeds : Matrix, shape(m, 1)
|
113 |
+
This is a matrix containing the generalized speeds of the system
|
114 |
+
|
115 |
+
states : Matrix, shape(o, 1)
|
116 |
+
This is a matrix containing the state variables of the system
|
117 |
+
|
118 |
+
alg_con : List
|
119 |
+
This list contains the indices of the algebraic constraints in the
|
120 |
+
combined equations of motion. The presence of these constraints
|
121 |
+
requires that a DAE solver be used instead of an ODE solver.
|
122 |
+
If the system is given in form [3] the alg_con variable will be
|
123 |
+
adjusted such that it is a representation of the combined kinematics
|
124 |
+
and dynamics thus make sure it always matches the mass matrix
|
125 |
+
entered.
|
126 |
+
|
127 |
+
dyn_implicit_mat : Matrix, shape(m, m)
|
128 |
+
This is the M matrix in form [3] of the equations of motion (the mass
|
129 |
+
matrix or generalized inertia matrix of the dynamical equations of
|
130 |
+
motion in implicit form).
|
131 |
+
|
132 |
+
dyn_implicit_rhs : Matrix, shape(m, 1)
|
133 |
+
This is the F vector in form [3] of the equations of motion (the right
|
134 |
+
hand side of the dynamical equations of motion in implicit form).
|
135 |
+
|
136 |
+
comb_implicit_mat : Matrix, shape(o, o)
|
137 |
+
This is the M matrix in form [2] of the equations of motion.
|
138 |
+
This matrix contains a block diagonal structure where the top
|
139 |
+
left block (the first rows) represent the matrix in the
|
140 |
+
implicit form of the kinematical equations and the bottom right
|
141 |
+
block (the last rows) represent the matrix in the implicit form
|
142 |
+
of the dynamical equations.
|
143 |
+
|
144 |
+
comb_implicit_rhs : Matrix, shape(o, 1)
|
145 |
+
This is the F vector in form [2] of the equations of motion. The top
|
146 |
+
part of the vector represents the right hand side of the implicit form
|
147 |
+
of the kinemaical equations and the bottom of the vector represents the
|
148 |
+
right hand side of the implicit form of the dynamical equations of
|
149 |
+
motion.
|
150 |
+
|
151 |
+
comb_explicit_rhs : Matrix, shape(o, 1)
|
152 |
+
This vector represents the right hand side of the combined equations of
|
153 |
+
motion in explicit form (form [1] from above).
|
154 |
+
|
155 |
+
kin_explicit_rhs : Matrix, shape(m, 1)
|
156 |
+
This is the right hand side of the explicit form of the kinematical
|
157 |
+
equations of motion as can be seen in form [3] (the G matrix).
|
158 |
+
|
159 |
+
output_eqns : Dictionary
|
160 |
+
If output equations were given they are stored in a dictionary where
|
161 |
+
the key corresponds to the name given for the specific equation and
|
162 |
+
the value is the equation itself in symbolic form
|
163 |
+
|
164 |
+
bodies : Tuple
|
165 |
+
If the bodies in the system were given they are stored in a tuple for
|
166 |
+
future access
|
167 |
+
|
168 |
+
loads : Tuple
|
169 |
+
If the loads in the system were given they are stored in a tuple for
|
170 |
+
future access. This includes forces and torques where forces are given
|
171 |
+
by (point of application, force vector) and torques are given by
|
172 |
+
(reference frame acted upon, torque vector).
|
173 |
+
|
174 |
+
Example
|
175 |
+
=======
|
176 |
+
|
177 |
+
As a simple example, the dynamics of a simple pendulum will be input into a
|
178 |
+
SymbolicSystem object manually. First some imports will be needed and then
|
179 |
+
symbols will be set up for the length of the pendulum (l), mass at the end
|
180 |
+
of the pendulum (m), and a constant for gravity (g). ::
|
181 |
+
|
182 |
+
>>> from sympy import Matrix, sin, symbols
|
183 |
+
>>> from sympy.physics.mechanics import dynamicsymbols, SymbolicSystem
|
184 |
+
>>> l, m, g = symbols('l m g')
|
185 |
+
|
186 |
+
The system will be defined by an angle of theta from the vertical and a
|
187 |
+
generalized speed of omega will be used where omega = theta_dot. ::
|
188 |
+
|
189 |
+
>>> theta, omega = dynamicsymbols('theta omega')
|
190 |
+
|
191 |
+
Now the equations of motion are ready to be formed and passed to the
|
192 |
+
SymbolicSystem object. ::
|
193 |
+
|
194 |
+
>>> kin_explicit_rhs = Matrix([omega])
|
195 |
+
>>> dyn_implicit_mat = Matrix([l**2 * m])
|
196 |
+
>>> dyn_implicit_rhs = Matrix([-g * l * m * sin(theta)])
|
197 |
+
>>> symsystem = SymbolicSystem([theta], dyn_implicit_rhs, [omega],
|
198 |
+
... dyn_implicit_mat)
|
199 |
+
|
200 |
+
Notes
|
201 |
+
=====
|
202 |
+
|
203 |
+
m : number of generalized speeds
|
204 |
+
n : number of generalized coordinates
|
205 |
+
o : number of states
|
206 |
+
|
207 |
+
"""
|
208 |
+
|
209 |
+
def __init__(self, coord_states, right_hand_side, speeds=None,
|
210 |
+
mass_matrix=None, coordinate_derivatives=None, alg_con=None,
|
211 |
+
output_eqns={}, coord_idxs=None, speed_idxs=None, bodies=None,
|
212 |
+
loads=None):
|
213 |
+
"""Initializes a SymbolicSystem object"""
|
214 |
+
|
215 |
+
# Extract information on speeds, coordinates and states
|
216 |
+
if speeds is None:
|
217 |
+
self._states = Matrix(coord_states)
|
218 |
+
|
219 |
+
if coord_idxs is None:
|
220 |
+
self._coordinates = None
|
221 |
+
else:
|
222 |
+
coords = [coord_states[i] for i in coord_idxs]
|
223 |
+
self._coordinates = Matrix(coords)
|
224 |
+
|
225 |
+
if speed_idxs is None:
|
226 |
+
self._speeds = None
|
227 |
+
else:
|
228 |
+
speeds_inter = [coord_states[i] for i in speed_idxs]
|
229 |
+
self._speeds = Matrix(speeds_inter)
|
230 |
+
else:
|
231 |
+
self._coordinates = Matrix(coord_states)
|
232 |
+
self._speeds = Matrix(speeds)
|
233 |
+
self._states = self._coordinates.col_join(self._speeds)
|
234 |
+
|
235 |
+
# Extract equations of motion form
|
236 |
+
if coordinate_derivatives is not None:
|
237 |
+
self._kin_explicit_rhs = coordinate_derivatives
|
238 |
+
self._dyn_implicit_rhs = right_hand_side
|
239 |
+
self._dyn_implicit_mat = mass_matrix
|
240 |
+
self._comb_implicit_rhs = None
|
241 |
+
self._comb_implicit_mat = None
|
242 |
+
self._comb_explicit_rhs = None
|
243 |
+
elif mass_matrix is not None:
|
244 |
+
self._kin_explicit_rhs = None
|
245 |
+
self._dyn_implicit_rhs = None
|
246 |
+
self._dyn_implicit_mat = None
|
247 |
+
self._comb_implicit_rhs = right_hand_side
|
248 |
+
self._comb_implicit_mat = mass_matrix
|
249 |
+
self._comb_explicit_rhs = None
|
250 |
+
else:
|
251 |
+
self._kin_explicit_rhs = None
|
252 |
+
self._dyn_implicit_rhs = None
|
253 |
+
self._dyn_implicit_mat = None
|
254 |
+
self._comb_implicit_rhs = None
|
255 |
+
self._comb_implicit_mat = None
|
256 |
+
self._comb_explicit_rhs = right_hand_side
|
257 |
+
|
258 |
+
# Set the remainder of the inputs as instance attributes
|
259 |
+
if alg_con is not None and coordinate_derivatives is not None:
|
260 |
+
alg_con = [i + len(coordinate_derivatives) for i in alg_con]
|
261 |
+
self._alg_con = alg_con
|
262 |
+
self.output_eqns = output_eqns
|
263 |
+
|
264 |
+
# Change the body and loads iterables to tuples if they are not tuples
|
265 |
+
# already
|
266 |
+
if not isinstance(bodies, tuple) and bodies is not None:
|
267 |
+
bodies = tuple(bodies)
|
268 |
+
if not isinstance(loads, tuple) and loads is not None:
|
269 |
+
loads = tuple(loads)
|
270 |
+
self._bodies = bodies
|
271 |
+
self._loads = loads
|
272 |
+
|
273 |
+
@property
|
274 |
+
def coordinates(self):
|
275 |
+
"""Returns the column matrix of the generalized coordinates"""
|
276 |
+
if self._coordinates is None:
|
277 |
+
raise AttributeError("The coordinates were not specified.")
|
278 |
+
else:
|
279 |
+
return self._coordinates
|
280 |
+
|
281 |
+
@property
|
282 |
+
def speeds(self):
|
283 |
+
"""Returns the column matrix of generalized speeds"""
|
284 |
+
if self._speeds is None:
|
285 |
+
raise AttributeError("The speeds were not specified.")
|
286 |
+
else:
|
287 |
+
return self._speeds
|
288 |
+
|
289 |
+
@property
|
290 |
+
def states(self):
|
291 |
+
"""Returns the column matrix of the state variables"""
|
292 |
+
return self._states
|
293 |
+
|
294 |
+
@property
|
295 |
+
def alg_con(self):
|
296 |
+
"""Returns a list with the indices of the rows containing algebraic
|
297 |
+
constraints in the combined form of the equations of motion"""
|
298 |
+
return self._alg_con
|
299 |
+
|
300 |
+
@property
|
301 |
+
def dyn_implicit_mat(self):
|
302 |
+
"""Returns the matrix, M, corresponding to the dynamic equations in
|
303 |
+
implicit form, M x' = F, where the kinematical equations are not
|
304 |
+
included"""
|
305 |
+
if self._dyn_implicit_mat is None:
|
306 |
+
raise AttributeError("dyn_implicit_mat is not specified for "
|
307 |
+
"equations of motion form [1] or [2].")
|
308 |
+
else:
|
309 |
+
return self._dyn_implicit_mat
|
310 |
+
|
311 |
+
@property
|
312 |
+
def dyn_implicit_rhs(self):
|
313 |
+
"""Returns the column matrix, F, corresponding to the dynamic equations
|
314 |
+
in implicit form, M x' = F, where the kinematical equations are not
|
315 |
+
included"""
|
316 |
+
if self._dyn_implicit_rhs is None:
|
317 |
+
raise AttributeError("dyn_implicit_rhs is not specified for "
|
318 |
+
"equations of motion form [1] or [2].")
|
319 |
+
else:
|
320 |
+
return self._dyn_implicit_rhs
|
321 |
+
|
322 |
+
@property
|
323 |
+
def comb_implicit_mat(self):
|
324 |
+
"""Returns the matrix, M, corresponding to the equations of motion in
|
325 |
+
implicit form (form [2]), M x' = F, where the kinematical equations are
|
326 |
+
included"""
|
327 |
+
if self._comb_implicit_mat is None:
|
328 |
+
if self._dyn_implicit_mat is not None:
|
329 |
+
num_kin_eqns = len(self._kin_explicit_rhs)
|
330 |
+
num_dyn_eqns = len(self._dyn_implicit_rhs)
|
331 |
+
zeros1 = zeros(num_kin_eqns, num_dyn_eqns)
|
332 |
+
zeros2 = zeros(num_dyn_eqns, num_kin_eqns)
|
333 |
+
inter1 = eye(num_kin_eqns).row_join(zeros1)
|
334 |
+
inter2 = zeros2.row_join(self._dyn_implicit_mat)
|
335 |
+
self._comb_implicit_mat = inter1.col_join(inter2)
|
336 |
+
return self._comb_implicit_mat
|
337 |
+
else:
|
338 |
+
raise AttributeError("comb_implicit_mat is not specified for "
|
339 |
+
"equations of motion form [1].")
|
340 |
+
else:
|
341 |
+
return self._comb_implicit_mat
|
342 |
+
|
343 |
+
@property
|
344 |
+
def comb_implicit_rhs(self):
|
345 |
+
"""Returns the column matrix, F, corresponding to the equations of
|
346 |
+
motion in implicit form (form [2]), M x' = F, where the kinematical
|
347 |
+
equations are included"""
|
348 |
+
if self._comb_implicit_rhs is None:
|
349 |
+
if self._dyn_implicit_rhs is not None:
|
350 |
+
kin_inter = self._kin_explicit_rhs
|
351 |
+
dyn_inter = self._dyn_implicit_rhs
|
352 |
+
self._comb_implicit_rhs = kin_inter.col_join(dyn_inter)
|
353 |
+
return self._comb_implicit_rhs
|
354 |
+
else:
|
355 |
+
raise AttributeError("comb_implicit_mat is not specified for "
|
356 |
+
"equations of motion in form [1].")
|
357 |
+
else:
|
358 |
+
return self._comb_implicit_rhs
|
359 |
+
|
360 |
+
def compute_explicit_form(self):
|
361 |
+
"""If the explicit right hand side of the combined equations of motion
|
362 |
+
is to provided upon initialization, this method will calculate it. This
|
363 |
+
calculation can potentially take awhile to compute."""
|
364 |
+
if self._comb_explicit_rhs is not None:
|
365 |
+
raise AttributeError("comb_explicit_rhs is already formed.")
|
366 |
+
|
367 |
+
inter1 = getattr(self, 'kin_explicit_rhs', None)
|
368 |
+
if inter1 is not None:
|
369 |
+
inter2 = self._dyn_implicit_mat.LUsolve(self._dyn_implicit_rhs)
|
370 |
+
out = inter1.col_join(inter2)
|
371 |
+
else:
|
372 |
+
out = self._comb_implicit_mat.LUsolve(self._comb_implicit_rhs)
|
373 |
+
|
374 |
+
self._comb_explicit_rhs = out
|
375 |
+
|
376 |
+
@property
|
377 |
+
def comb_explicit_rhs(self):
|
378 |
+
"""Returns the right hand side of the equations of motion in explicit
|
379 |
+
form, x' = F, where the kinematical equations are included"""
|
380 |
+
if self._comb_explicit_rhs is None:
|
381 |
+
raise AttributeError("Please run .combute_explicit_form before "
|
382 |
+
"attempting to access comb_explicit_rhs.")
|
383 |
+
else:
|
384 |
+
return self._comb_explicit_rhs
|
385 |
+
|
386 |
+
@property
|
387 |
+
def kin_explicit_rhs(self):
|
388 |
+
"""Returns the right hand side of the kinematical equations in explicit
|
389 |
+
form, q' = G"""
|
390 |
+
if self._kin_explicit_rhs is None:
|
391 |
+
raise AttributeError("kin_explicit_rhs is not specified for "
|
392 |
+
"equations of motion form [1] or [2].")
|
393 |
+
else:
|
394 |
+
return self._kin_explicit_rhs
|
395 |
+
|
396 |
+
def dynamic_symbols(self):
|
397 |
+
"""Returns a column matrix containing all of the symbols in the system
|
398 |
+
that depend on time"""
|
399 |
+
# Create a list of all of the expressions in the equations of motion
|
400 |
+
if self._comb_explicit_rhs is None:
|
401 |
+
eom_expressions = (self.comb_implicit_mat[:] +
|
402 |
+
self.comb_implicit_rhs[:])
|
403 |
+
else:
|
404 |
+
eom_expressions = (self._comb_explicit_rhs[:])
|
405 |
+
|
406 |
+
functions_of_time = set()
|
407 |
+
for expr in eom_expressions:
|
408 |
+
functions_of_time = functions_of_time.union(
|
409 |
+
find_dynamicsymbols(expr))
|
410 |
+
functions_of_time = functions_of_time.union(self._states)
|
411 |
+
|
412 |
+
return tuple(functions_of_time)
|
413 |
+
|
414 |
+
def constant_symbols(self):
|
415 |
+
"""Returns a column matrix containing all of the symbols in the system
|
416 |
+
that do not depend on time"""
|
417 |
+
# Create a list of all of the expressions in the equations of motion
|
418 |
+
if self._comb_explicit_rhs is None:
|
419 |
+
eom_expressions = (self.comb_implicit_mat[:] +
|
420 |
+
self.comb_implicit_rhs[:])
|
421 |
+
else:
|
422 |
+
eom_expressions = (self._comb_explicit_rhs[:])
|
423 |
+
|
424 |
+
constants = set()
|
425 |
+
for expr in eom_expressions:
|
426 |
+
constants = constants.union(expr.free_symbols)
|
427 |
+
constants.remove(dynamicsymbols._t)
|
428 |
+
|
429 |
+
return tuple(constants)
|
430 |
+
|
431 |
+
@property
|
432 |
+
def bodies(self):
|
433 |
+
"""Returns the bodies in the system"""
|
434 |
+
if self._bodies is None:
|
435 |
+
raise AttributeError("bodies were not specified for the system.")
|
436 |
+
else:
|
437 |
+
return self._bodies
|
438 |
+
|
439 |
+
@property
|
440 |
+
def loads(self):
|
441 |
+
"""Returns the loads in the system"""
|
442 |
+
if self._loads is None:
|
443 |
+
raise AttributeError("loads were not specified for the system.")
|
444 |
+
else:
|
445 |
+
return self._loads
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/__pycache__/test_joint.cpython-310.pyc
ADDED
Binary file (39.5 kB). View file
|
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/__pycache__/test_lagrange2.cpython-310.pyc
ADDED
Binary file (1.21 kB). View file
|
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/__pycache__/test_models.cpython-310.pyc
ADDED
Binary file (4.25 kB). View file
|
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/__pycache__/test_particle.cpython-310.pyc
ADDED
Binary file (2.54 kB). View file
|
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/__pycache__/test_system.cpython-310.pyc
ADDED
Binary file (5.96 kB). View file
|
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_joint.py
ADDED
@@ -0,0 +1,1144 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.core.function import expand_mul
|
2 |
+
from sympy.core.numbers import pi
|
3 |
+
from sympy.core.singleton import S
|
4 |
+
from sympy.functions.elementary.miscellaneous import sqrt
|
5 |
+
from sympy.functions.elementary.trigonometric import (cos, sin)
|
6 |
+
from sympy.core.backend import Matrix, _simplify_matrix, eye, zeros
|
7 |
+
from sympy.core.symbol import symbols
|
8 |
+
from sympy.physics.mechanics import (dynamicsymbols, Body, JointsMethod,
|
9 |
+
PinJoint, PrismaticJoint, CylindricalJoint,
|
10 |
+
PlanarJoint, SphericalJoint, WeldJoint)
|
11 |
+
from sympy.physics.mechanics.joint import Joint
|
12 |
+
from sympy.physics.vector import Vector, ReferenceFrame, Point
|
13 |
+
from sympy.testing.pytest import raises, warns_deprecated_sympy
|
14 |
+
|
15 |
+
|
16 |
+
Vector.simp = True
|
17 |
+
t = dynamicsymbols._t # type: ignore
|
18 |
+
|
19 |
+
|
20 |
+
def _generate_body(interframe=False):
|
21 |
+
N = ReferenceFrame('N')
|
22 |
+
A = ReferenceFrame('A')
|
23 |
+
P = Body('P', frame=N)
|
24 |
+
C = Body('C', frame=A)
|
25 |
+
if interframe:
|
26 |
+
Pint, Cint = ReferenceFrame('P_int'), ReferenceFrame('C_int')
|
27 |
+
Pint.orient_axis(N, N.x, pi)
|
28 |
+
Cint.orient_axis(A, A.y, -pi / 2)
|
29 |
+
return N, A, P, C, Pint, Cint
|
30 |
+
return N, A, P, C
|
31 |
+
|
32 |
+
|
33 |
+
def test_Joint():
|
34 |
+
parent = Body('parent')
|
35 |
+
child = Body('child')
|
36 |
+
raises(TypeError, lambda: Joint('J', parent, child))
|
37 |
+
|
38 |
+
|
39 |
+
def test_coordinate_generation():
|
40 |
+
q, u, qj, uj = dynamicsymbols('q u q_J u_J')
|
41 |
+
q0j, q1j, q2j, q3j, u0j, u1j, u2j, u3j = dynamicsymbols('q0:4_J u0:4_J')
|
42 |
+
q0, q1, q2, q3, u0, u1, u2, u3 = dynamicsymbols('q0:4 u0:4')
|
43 |
+
_, _, P, C = _generate_body()
|
44 |
+
# Using PinJoint to access Joint's coordinate generation method
|
45 |
+
J = PinJoint('J', P, C)
|
46 |
+
# Test single given
|
47 |
+
assert J._fill_coordinate_list(q, 1) == Matrix([q])
|
48 |
+
assert J._fill_coordinate_list([u], 1) == Matrix([u])
|
49 |
+
assert J._fill_coordinate_list([u], 1, offset=2) == Matrix([u])
|
50 |
+
# Test None
|
51 |
+
assert J._fill_coordinate_list(None, 1) == Matrix([qj])
|
52 |
+
assert J._fill_coordinate_list([None], 1) == Matrix([qj])
|
53 |
+
assert J._fill_coordinate_list([q0, None, None], 3) == Matrix(
|
54 |
+
[q0, q1j, q2j])
|
55 |
+
# Test autofill
|
56 |
+
assert J._fill_coordinate_list(None, 3) == Matrix([q0j, q1j, q2j])
|
57 |
+
assert J._fill_coordinate_list([], 3) == Matrix([q0j, q1j, q2j])
|
58 |
+
# Test offset
|
59 |
+
assert J._fill_coordinate_list([], 3, offset=1) == Matrix([q1j, q2j, q3j])
|
60 |
+
assert J._fill_coordinate_list([q1, None, q3], 3, offset=1) == Matrix(
|
61 |
+
[q1, q2j, q3])
|
62 |
+
assert J._fill_coordinate_list(None, 2, offset=2) == Matrix([q2j, q3j])
|
63 |
+
# Test label
|
64 |
+
assert J._fill_coordinate_list(None, 1, 'u') == Matrix([uj])
|
65 |
+
assert J._fill_coordinate_list([], 3, 'u') == Matrix([u0j, u1j, u2j])
|
66 |
+
# Test single numbering
|
67 |
+
assert J._fill_coordinate_list(None, 1, number_single=True) == Matrix([q0j])
|
68 |
+
assert J._fill_coordinate_list([], 1, 'u', 2, True) == Matrix([u2j])
|
69 |
+
assert J._fill_coordinate_list([], 3, 'q') == Matrix([q0j, q1j, q2j])
|
70 |
+
# Test invalid number of coordinates supplied
|
71 |
+
raises(ValueError, lambda: J._fill_coordinate_list([q0, q1], 1))
|
72 |
+
raises(ValueError, lambda: J._fill_coordinate_list([u0, u1, None], 2, 'u'))
|
73 |
+
raises(ValueError, lambda: J._fill_coordinate_list([q0, q1], 3))
|
74 |
+
# Test incorrect coordinate type
|
75 |
+
raises(TypeError, lambda: J._fill_coordinate_list([q0, symbols('q1')], 2))
|
76 |
+
raises(TypeError, lambda: J._fill_coordinate_list([q0 + q1, q1], 2))
|
77 |
+
# Test if derivative as generalized speed is allowed
|
78 |
+
_, _, P, C = _generate_body()
|
79 |
+
PinJoint('J', P, C, q1, q1.diff(t))
|
80 |
+
# Test duplicate coordinates
|
81 |
+
_, _, P, C = _generate_body()
|
82 |
+
raises(ValueError, lambda: SphericalJoint('J', P, C, [q1j, None, None]))
|
83 |
+
raises(ValueError, lambda: SphericalJoint('J', P, C, speeds=[u0, u0, u1]))
|
84 |
+
|
85 |
+
|
86 |
+
def test_pin_joint():
|
87 |
+
P = Body('P')
|
88 |
+
C = Body('C')
|
89 |
+
l, m = symbols('l m')
|
90 |
+
q, u = dynamicsymbols('q_J, u_J')
|
91 |
+
Pj = PinJoint('J', P, C)
|
92 |
+
assert Pj.name == 'J'
|
93 |
+
assert Pj.parent == P
|
94 |
+
assert Pj.child == C
|
95 |
+
assert Pj.coordinates == Matrix([q])
|
96 |
+
assert Pj.speeds == Matrix([u])
|
97 |
+
assert Pj.kdes == Matrix([u - q.diff(t)])
|
98 |
+
assert Pj.joint_axis == P.frame.x
|
99 |
+
assert Pj.child_point.pos_from(C.masscenter) == Vector(0)
|
100 |
+
assert Pj.parent_point.pos_from(P.masscenter) == Vector(0)
|
101 |
+
assert Pj.parent_point.pos_from(Pj._child_point) == Vector(0)
|
102 |
+
assert C.masscenter.pos_from(P.masscenter) == Vector(0)
|
103 |
+
assert Pj.parent_interframe == P.frame
|
104 |
+
assert Pj.child_interframe == C.frame
|
105 |
+
assert Pj.__str__() == 'PinJoint: J parent: P child: C'
|
106 |
+
|
107 |
+
P1 = Body('P1')
|
108 |
+
C1 = Body('C1')
|
109 |
+
Pint = ReferenceFrame('P_int')
|
110 |
+
Pint.orient_axis(P1.frame, P1.y, pi / 2)
|
111 |
+
J1 = PinJoint('J1', P1, C1, parent_point=l*P1.frame.x,
|
112 |
+
child_point=m*C1.frame.y, joint_axis=P1.frame.z,
|
113 |
+
parent_interframe=Pint)
|
114 |
+
assert J1._joint_axis == P1.frame.z
|
115 |
+
assert J1._child_point.pos_from(C1.masscenter) == m * C1.frame.y
|
116 |
+
assert J1._parent_point.pos_from(P1.masscenter) == l * P1.frame.x
|
117 |
+
assert J1._parent_point.pos_from(J1._child_point) == Vector(0)
|
118 |
+
assert (P1.masscenter.pos_from(C1.masscenter) ==
|
119 |
+
-l*P1.frame.x + m*C1.frame.y)
|
120 |
+
assert J1.parent_interframe == Pint
|
121 |
+
assert J1.child_interframe == C1.frame
|
122 |
+
|
123 |
+
q, u = dynamicsymbols('q, u')
|
124 |
+
N, A, P, C, Pint, Cint = _generate_body(True)
|
125 |
+
parent_point = P.masscenter.locatenew('parent_point', N.x + N.y)
|
126 |
+
child_point = C.masscenter.locatenew('child_point', C.y + C.z)
|
127 |
+
J = PinJoint('J', P, C, q, u, parent_point=parent_point,
|
128 |
+
child_point=child_point, parent_interframe=Pint,
|
129 |
+
child_interframe=Cint, joint_axis=N.z)
|
130 |
+
assert J.joint_axis == N.z
|
131 |
+
assert J.parent_point.vel(N) == 0
|
132 |
+
assert J.parent_point == parent_point
|
133 |
+
assert J.child_point == child_point
|
134 |
+
assert J.child_point.pos_from(P.masscenter) == N.x + N.y
|
135 |
+
assert J.parent_point.pos_from(C.masscenter) == C.y + C.z
|
136 |
+
assert C.masscenter.pos_from(P.masscenter) == N.x + N.y - C.y - C.z
|
137 |
+
assert C.masscenter.vel(N).express(N) == (u * sin(q) - u * cos(q)) * N.x + (
|
138 |
+
-u * sin(q) - u * cos(q)) * N.y
|
139 |
+
assert J.parent_interframe == Pint
|
140 |
+
assert J.child_interframe == Cint
|
141 |
+
|
142 |
+
|
143 |
+
def test_pin_joint_double_pendulum():
|
144 |
+
q1, q2 = dynamicsymbols('q1 q2')
|
145 |
+
u1, u2 = dynamicsymbols('u1 u2')
|
146 |
+
m, l = symbols('m l')
|
147 |
+
N = ReferenceFrame('N')
|
148 |
+
A = ReferenceFrame('A')
|
149 |
+
B = ReferenceFrame('B')
|
150 |
+
C = Body('C', frame=N) # ceiling
|
151 |
+
PartP = Body('P', frame=A, mass=m)
|
152 |
+
PartR = Body('R', frame=B, mass=m)
|
153 |
+
|
154 |
+
J1 = PinJoint('J1', C, PartP, speeds=u1, coordinates=q1,
|
155 |
+
child_point=-l*A.x, joint_axis=C.frame.z)
|
156 |
+
J2 = PinJoint('J2', PartP, PartR, speeds=u2, coordinates=q2,
|
157 |
+
child_point=-l*B.x, joint_axis=PartP.frame.z)
|
158 |
+
|
159 |
+
# Check orientation
|
160 |
+
assert N.dcm(A) == Matrix([[cos(q1), -sin(q1), 0],
|
161 |
+
[sin(q1), cos(q1), 0], [0, 0, 1]])
|
162 |
+
assert A.dcm(B) == Matrix([[cos(q2), -sin(q2), 0],
|
163 |
+
[sin(q2), cos(q2), 0], [0, 0, 1]])
|
164 |
+
assert _simplify_matrix(N.dcm(B)) == Matrix([[cos(q1 + q2), -sin(q1 + q2), 0],
|
165 |
+
[sin(q1 + q2), cos(q1 + q2), 0],
|
166 |
+
[0, 0, 1]])
|
167 |
+
|
168 |
+
# Check Angular Velocity
|
169 |
+
assert A.ang_vel_in(N) == u1 * N.z
|
170 |
+
assert B.ang_vel_in(A) == u2 * A.z
|
171 |
+
assert B.ang_vel_in(N) == u1 * N.z + u2 * A.z
|
172 |
+
|
173 |
+
# Check kde
|
174 |
+
assert J1.kdes == Matrix([u1 - q1.diff(t)])
|
175 |
+
assert J2.kdes == Matrix([u2 - q2.diff(t)])
|
176 |
+
|
177 |
+
# Check Linear Velocity
|
178 |
+
assert PartP.masscenter.vel(N) == l*u1*A.y
|
179 |
+
assert PartR.masscenter.vel(A) == l*u2*B.y
|
180 |
+
assert PartR.masscenter.vel(N) == l*u1*A.y + l*(u1 + u2)*B.y
|
181 |
+
|
182 |
+
|
183 |
+
def test_pin_joint_chaos_pendulum():
|
184 |
+
mA, mB, lA, lB, h = symbols('mA, mB, lA, lB, h')
|
185 |
+
theta, phi, omega, alpha = dynamicsymbols('theta phi omega alpha')
|
186 |
+
N = ReferenceFrame('N')
|
187 |
+
A = ReferenceFrame('A')
|
188 |
+
B = ReferenceFrame('B')
|
189 |
+
lA = (lB - h / 2) / 2
|
190 |
+
lC = (lB/2 + h/4)
|
191 |
+
rod = Body('rod', frame=A, mass=mA)
|
192 |
+
plate = Body('plate', mass=mB, frame=B)
|
193 |
+
C = Body('C', frame=N)
|
194 |
+
J1 = PinJoint('J1', C, rod, coordinates=theta, speeds=omega,
|
195 |
+
child_point=lA*A.z, joint_axis=N.y)
|
196 |
+
J2 = PinJoint('J2', rod, plate, coordinates=phi, speeds=alpha,
|
197 |
+
parent_point=lC*A.z, joint_axis=A.z)
|
198 |
+
|
199 |
+
# Check orientation
|
200 |
+
assert A.dcm(N) == Matrix([[cos(theta), 0, -sin(theta)],
|
201 |
+
[0, 1, 0],
|
202 |
+
[sin(theta), 0, cos(theta)]])
|
203 |
+
assert A.dcm(B) == Matrix([[cos(phi), -sin(phi), 0],
|
204 |
+
[sin(phi), cos(phi), 0],
|
205 |
+
[0, 0, 1]])
|
206 |
+
assert B.dcm(N) == Matrix([
|
207 |
+
[cos(phi)*cos(theta), sin(phi), -sin(theta)*cos(phi)],
|
208 |
+
[-sin(phi)*cos(theta), cos(phi), sin(phi)*sin(theta)],
|
209 |
+
[sin(theta), 0, cos(theta)]])
|
210 |
+
|
211 |
+
# Check Angular Velocity
|
212 |
+
assert A.ang_vel_in(N) == omega*N.y
|
213 |
+
assert A.ang_vel_in(B) == -alpha*A.z
|
214 |
+
assert N.ang_vel_in(B) == -omega*N.y - alpha*A.z
|
215 |
+
|
216 |
+
# Check kde
|
217 |
+
assert J1.kdes == Matrix([omega - theta.diff(t)])
|
218 |
+
assert J2.kdes == Matrix([alpha - phi.diff(t)])
|
219 |
+
|
220 |
+
# Check pos of masscenters
|
221 |
+
assert C.masscenter.pos_from(rod.masscenter) == lA*A.z
|
222 |
+
assert rod.masscenter.pos_from(plate.masscenter) == - lC * A.z
|
223 |
+
|
224 |
+
# Check Linear Velocities
|
225 |
+
assert rod.masscenter.vel(N) == (h/4 - lB/2)*omega*A.x
|
226 |
+
assert plate.masscenter.vel(N) == ((h/4 - lB/2)*omega +
|
227 |
+
(h/4 + lB/2)*omega)*A.x
|
228 |
+
|
229 |
+
|
230 |
+
def test_pin_joint_interframe():
|
231 |
+
q, u = dynamicsymbols('q, u')
|
232 |
+
# Check not connected
|
233 |
+
N, A, P, C = _generate_body()
|
234 |
+
Pint, Cint = ReferenceFrame('Pint'), ReferenceFrame('Cint')
|
235 |
+
raises(ValueError, lambda: PinJoint('J', P, C, parent_interframe=Pint))
|
236 |
+
raises(ValueError, lambda: PinJoint('J', P, C, child_interframe=Cint))
|
237 |
+
# Check not fixed interframe
|
238 |
+
Pint.orient_axis(N, N.z, q)
|
239 |
+
Cint.orient_axis(A, A.z, q)
|
240 |
+
raises(ValueError, lambda: PinJoint('J', P, C, parent_interframe=Pint))
|
241 |
+
raises(ValueError, lambda: PinJoint('J', P, C, child_interframe=Cint))
|
242 |
+
# Check only parent_interframe
|
243 |
+
N, A, P, C = _generate_body()
|
244 |
+
Pint = ReferenceFrame('Pint')
|
245 |
+
Pint.orient_body_fixed(N, (pi / 4, pi, pi / 3), 'xyz')
|
246 |
+
PinJoint('J', P, C, q, u, parent_point=N.x, child_point=-C.y,
|
247 |
+
parent_interframe=Pint, joint_axis=Pint.x)
|
248 |
+
assert _simplify_matrix(N.dcm(A)) - Matrix([
|
249 |
+
[-1 / 2, sqrt(3) * cos(q) / 2, -sqrt(3) * sin(q) / 2],
|
250 |
+
[sqrt(6) / 4, sqrt(2) * (2 * sin(q) + cos(q)) / 4,
|
251 |
+
sqrt(2) * (-sin(q) + 2 * cos(q)) / 4],
|
252 |
+
[sqrt(6) / 4, sqrt(2) * (-2 * sin(q) + cos(q)) / 4,
|
253 |
+
-sqrt(2) * (sin(q) + 2 * cos(q)) / 4]]) == zeros(3)
|
254 |
+
assert A.ang_vel_in(N) == u * Pint.x
|
255 |
+
assert C.masscenter.pos_from(P.masscenter) == N.x + A.y
|
256 |
+
assert C.masscenter.vel(N) == u * A.z
|
257 |
+
assert P.masscenter.vel(Pint) == Vector(0)
|
258 |
+
assert C.masscenter.vel(Pint) == u * A.z
|
259 |
+
# Check only child_interframe
|
260 |
+
N, A, P, C = _generate_body()
|
261 |
+
Cint = ReferenceFrame('Cint')
|
262 |
+
Cint.orient_body_fixed(A, (2 * pi / 3, -pi, pi / 2), 'xyz')
|
263 |
+
PinJoint('J', P, C, q, u, parent_point=-N.z, child_point=C.x,
|
264 |
+
child_interframe=Cint, joint_axis=P.x + P.z)
|
265 |
+
assert _simplify_matrix(N.dcm(A)) == Matrix([
|
266 |
+
[-sqrt(2) * sin(q) / 2,
|
267 |
+
-sqrt(3) * (cos(q) - 1) / 4 - cos(q) / 4 - S(1) / 4,
|
268 |
+
sqrt(3) * (cos(q) + 1) / 4 - cos(q) / 4 + S(1) / 4],
|
269 |
+
[cos(q), (sqrt(2) + sqrt(6)) * -sin(q) / 4,
|
270 |
+
(-sqrt(2) + sqrt(6)) * sin(q) / 4],
|
271 |
+
[sqrt(2) * sin(q) / 2,
|
272 |
+
sqrt(3) * (cos(q) + 1) / 4 + cos(q) / 4 - S(1) / 4,
|
273 |
+
sqrt(3) * (1 - cos(q)) / 4 + cos(q) / 4 + S(1) / 4]])
|
274 |
+
assert A.ang_vel_in(N) == sqrt(2) * u / 2 * N.x + sqrt(2) * u / 2 * N.z
|
275 |
+
assert C.masscenter.pos_from(P.masscenter) == - N.z - A.x
|
276 |
+
assert C.masscenter.vel(N).simplify() == (
|
277 |
+
-sqrt(6) - sqrt(2)) * u / 4 * A.y + (
|
278 |
+
-sqrt(2) + sqrt(6)) * u / 4 * A.z
|
279 |
+
assert C.masscenter.vel(Cint) == Vector(0)
|
280 |
+
# Check combination
|
281 |
+
N, A, P, C = _generate_body()
|
282 |
+
Pint, Cint = ReferenceFrame('Pint'), ReferenceFrame('Cint')
|
283 |
+
Pint.orient_body_fixed(N, (-pi / 2, pi, pi / 2), 'xyz')
|
284 |
+
Cint.orient_body_fixed(A, (2 * pi / 3, -pi, pi / 2), 'xyz')
|
285 |
+
PinJoint('J', P, C, q, u, parent_point=N.x - N.y, child_point=-C.z,
|
286 |
+
parent_interframe=Pint, child_interframe=Cint,
|
287 |
+
joint_axis=Pint.x + Pint.z)
|
288 |
+
assert _simplify_matrix(N.dcm(A)) == Matrix([
|
289 |
+
[cos(q), (sqrt(2) + sqrt(6)) * -sin(q) / 4,
|
290 |
+
(-sqrt(2) + sqrt(6)) * sin(q) / 4],
|
291 |
+
[-sqrt(2) * sin(q) / 2,
|
292 |
+
-sqrt(3) * (cos(q) + 1) / 4 - cos(q) / 4 + S(1) / 4,
|
293 |
+
sqrt(3) * (cos(q) - 1) / 4 - cos(q) / 4 - S(1) / 4],
|
294 |
+
[sqrt(2) * sin(q) / 2,
|
295 |
+
sqrt(3) * (cos(q) - 1) / 4 + cos(q) / 4 + S(1) / 4,
|
296 |
+
-sqrt(3) * (cos(q) + 1) / 4 + cos(q) / 4 - S(1) / 4]])
|
297 |
+
assert A.ang_vel_in(N) == sqrt(2) * u / 2 * Pint.x + sqrt(
|
298 |
+
2) * u / 2 * Pint.z
|
299 |
+
assert C.masscenter.pos_from(P.masscenter) == N.x - N.y + A.z
|
300 |
+
N_v_C = (-sqrt(2) + sqrt(6)) * u / 4 * A.x
|
301 |
+
assert C.masscenter.vel(N).simplify() == N_v_C
|
302 |
+
assert C.masscenter.vel(Pint).simplify() == N_v_C
|
303 |
+
assert C.masscenter.vel(Cint) == Vector(0)
|
304 |
+
|
305 |
+
|
306 |
+
def test_pin_joint_joint_axis():
|
307 |
+
q, u = dynamicsymbols('q, u')
|
308 |
+
# Check parent as reference
|
309 |
+
N, A, P, C, Pint, Cint = _generate_body(True)
|
310 |
+
pin = PinJoint('J', P, C, q, u, parent_interframe=Pint,
|
311 |
+
child_interframe=Cint, joint_axis=P.y)
|
312 |
+
assert pin.joint_axis == P.y
|
313 |
+
assert N.dcm(A) == Matrix([[sin(q), 0, cos(q)], [0, -1, 0],
|
314 |
+
[cos(q), 0, -sin(q)]])
|
315 |
+
# Check parent_interframe as reference
|
316 |
+
N, A, P, C, Pint, Cint = _generate_body(True)
|
317 |
+
pin = PinJoint('J', P, C, q, u, parent_interframe=Pint,
|
318 |
+
child_interframe=Cint, joint_axis=Pint.y)
|
319 |
+
assert pin.joint_axis == Pint.y
|
320 |
+
assert N.dcm(A) == Matrix([[-sin(q), 0, cos(q)], [0, -1, 0],
|
321 |
+
[cos(q), 0, sin(q)]])
|
322 |
+
# Check combination of joint_axis with interframes supplied as vectors (2x)
|
323 |
+
N, A, P, C = _generate_body()
|
324 |
+
pin = PinJoint('J', P, C, q, u, parent_interframe=N.z,
|
325 |
+
child_interframe=-C.z, joint_axis=N.z)
|
326 |
+
assert pin.joint_axis == N.z
|
327 |
+
assert N.dcm(A) == Matrix([[-cos(q), -sin(q), 0], [-sin(q), cos(q), 0],
|
328 |
+
[0, 0, -1]])
|
329 |
+
N, A, P, C = _generate_body()
|
330 |
+
pin = PinJoint('J', P, C, q, u, parent_interframe=N.z,
|
331 |
+
child_interframe=-C.z, joint_axis=N.x)
|
332 |
+
assert pin.joint_axis == N.x
|
333 |
+
assert N.dcm(A) == Matrix([[-1, 0, 0], [0, cos(q), sin(q)],
|
334 |
+
[0, sin(q), -cos(q)]])
|
335 |
+
# Check time varying axis
|
336 |
+
N, A, P, C, Pint, Cint = _generate_body(True)
|
337 |
+
raises(ValueError, lambda: PinJoint('J', P, C,
|
338 |
+
joint_axis=cos(q) * N.x + sin(q) * N.y))
|
339 |
+
# Check joint_axis provided in child frame
|
340 |
+
raises(ValueError, lambda: PinJoint('J', P, C, joint_axis=C.x))
|
341 |
+
# Check some invalid combinations
|
342 |
+
raises(ValueError, lambda: PinJoint('J', P, C, joint_axis=P.x + C.y))
|
343 |
+
raises(ValueError, lambda: PinJoint(
|
344 |
+
'J', P, C, parent_interframe=Pint, child_interframe=Cint,
|
345 |
+
joint_axis=Pint.x + C.y))
|
346 |
+
raises(ValueError, lambda: PinJoint(
|
347 |
+
'J', P, C, parent_interframe=Pint, child_interframe=Cint,
|
348 |
+
joint_axis=P.x + Cint.y))
|
349 |
+
# Check valid special combination
|
350 |
+
N, A, P, C, Pint, Cint = _generate_body(True)
|
351 |
+
PinJoint('J', P, C, parent_interframe=Pint, child_interframe=Cint,
|
352 |
+
joint_axis=Pint.x + P.y)
|
353 |
+
# Check invalid zero vector
|
354 |
+
raises(Exception, lambda: PinJoint(
|
355 |
+
'J', P, C, parent_interframe=Pint, child_interframe=Cint,
|
356 |
+
joint_axis=Vector(0)))
|
357 |
+
raises(Exception, lambda: PinJoint(
|
358 |
+
'J', P, C, parent_interframe=Pint, child_interframe=Cint,
|
359 |
+
joint_axis=P.y + Pint.y))
|
360 |
+
|
361 |
+
|
362 |
+
def test_pin_joint_arbitrary_axis():
|
363 |
+
q, u = dynamicsymbols('q_J, u_J')
|
364 |
+
|
365 |
+
# When the bodies are attached though masscenters but axes are opposite.
|
366 |
+
N, A, P, C = _generate_body()
|
367 |
+
PinJoint('J', P, C, child_interframe=-A.x)
|
368 |
+
|
369 |
+
assert (-A.x).angle_between(N.x) == 0
|
370 |
+
assert -A.x.express(N) == N.x
|
371 |
+
assert A.dcm(N) == Matrix([[-1, 0, 0],
|
372 |
+
[0, -cos(q), -sin(q)],
|
373 |
+
[0, -sin(q), cos(q)]])
|
374 |
+
assert A.ang_vel_in(N) == u*N.x
|
375 |
+
assert A.ang_vel_in(N).magnitude() == sqrt(u**2)
|
376 |
+
assert C.masscenter.pos_from(P.masscenter) == 0
|
377 |
+
assert C.masscenter.pos_from(P.masscenter).express(N).simplify() == 0
|
378 |
+
assert C.masscenter.vel(N) == 0
|
379 |
+
|
380 |
+
# When axes are different and parent joint is at masscenter but child joint
|
381 |
+
# is at a unit vector from child masscenter.
|
382 |
+
N, A, P, C = _generate_body()
|
383 |
+
PinJoint('J', P, C, child_interframe=A.y, child_point=A.x)
|
384 |
+
|
385 |
+
assert A.y.angle_between(N.x) == 0 # Axis are aligned
|
386 |
+
assert A.y.express(N) == N.x
|
387 |
+
assert A.dcm(N) == Matrix([[0, -cos(q), -sin(q)],
|
388 |
+
[1, 0, 0],
|
389 |
+
[0, -sin(q), cos(q)]])
|
390 |
+
assert A.ang_vel_in(N) == u*N.x
|
391 |
+
assert A.ang_vel_in(N).express(A) == u * A.y
|
392 |
+
assert A.ang_vel_in(N).magnitude() == sqrt(u**2)
|
393 |
+
assert A.ang_vel_in(N).cross(A.y) == 0
|
394 |
+
assert C.masscenter.vel(N) == u*A.z
|
395 |
+
assert C.masscenter.pos_from(P.masscenter) == -A.x
|
396 |
+
assert (C.masscenter.pos_from(P.masscenter).express(N).simplify() ==
|
397 |
+
cos(q)*N.y + sin(q)*N.z)
|
398 |
+
assert C.masscenter.vel(N).angle_between(A.x) == pi/2
|
399 |
+
|
400 |
+
# Similar to previous case but wrt parent body
|
401 |
+
N, A, P, C = _generate_body()
|
402 |
+
PinJoint('J', P, C, parent_interframe=N.y, parent_point=N.x)
|
403 |
+
|
404 |
+
assert N.y.angle_between(A.x) == 0 # Axis are aligned
|
405 |
+
assert N.y.express(A) == A.x
|
406 |
+
assert A.dcm(N) == Matrix([[0, 1, 0],
|
407 |
+
[-cos(q), 0, sin(q)],
|
408 |
+
[sin(q), 0, cos(q)]])
|
409 |
+
assert A.ang_vel_in(N) == u*N.y
|
410 |
+
assert A.ang_vel_in(N).express(A) == u*A.x
|
411 |
+
assert A.ang_vel_in(N).magnitude() == sqrt(u**2)
|
412 |
+
angle = A.ang_vel_in(N).angle_between(A.x)
|
413 |
+
assert angle.xreplace({u: 1}) == 0
|
414 |
+
assert C.masscenter.vel(N) == 0
|
415 |
+
assert C.masscenter.pos_from(P.masscenter) == N.x
|
416 |
+
|
417 |
+
# Both joint pos id defined but different axes
|
418 |
+
N, A, P, C = _generate_body()
|
419 |
+
PinJoint('J', P, C, parent_point=N.x, child_point=A.x,
|
420 |
+
child_interframe=A.x + A.y)
|
421 |
+
assert expand_mul(N.x.angle_between(A.x + A.y)) == 0 # Axis are aligned
|
422 |
+
assert (A.x + A.y).express(N).simplify() == sqrt(2)*N.x
|
423 |
+
assert _simplify_matrix(A.dcm(N)) == Matrix([
|
424 |
+
[sqrt(2)/2, -sqrt(2)*cos(q)/2, -sqrt(2)*sin(q)/2],
|
425 |
+
[sqrt(2)/2, sqrt(2)*cos(q)/2, sqrt(2)*sin(q)/2],
|
426 |
+
[0, -sin(q), cos(q)]])
|
427 |
+
assert A.ang_vel_in(N) == u*N.x
|
428 |
+
assert (A.ang_vel_in(N).express(A).simplify() ==
|
429 |
+
(u*A.x + u*A.y)/sqrt(2))
|
430 |
+
assert A.ang_vel_in(N).magnitude() == sqrt(u**2)
|
431 |
+
angle = A.ang_vel_in(N).angle_between(A.x + A.y)
|
432 |
+
assert angle.xreplace({u: 1}) == 0
|
433 |
+
assert C.masscenter.vel(N).simplify() == (u * A.z)/sqrt(2)
|
434 |
+
assert C.masscenter.pos_from(P.masscenter) == N.x - A.x
|
435 |
+
assert (C.masscenter.pos_from(P.masscenter).express(N).simplify() ==
|
436 |
+
(1 - sqrt(2)/2)*N.x + sqrt(2)*cos(q)/2*N.y +
|
437 |
+
sqrt(2)*sin(q)/2*N.z)
|
438 |
+
assert (C.masscenter.vel(N).express(N).simplify() ==
|
439 |
+
-sqrt(2)*u*sin(q)/2*N.y + sqrt(2)*u*cos(q)/2*N.z)
|
440 |
+
assert C.masscenter.vel(N).angle_between(A.x) == pi/2
|
441 |
+
|
442 |
+
N, A, P, C = _generate_body()
|
443 |
+
PinJoint('J', P, C, parent_point=N.x, child_point=A.x,
|
444 |
+
child_interframe=A.x + A.y - A.z)
|
445 |
+
assert expand_mul(N.x.angle_between(A.x + A.y - A.z)) == 0 # Axis aligned
|
446 |
+
assert (A.x + A.y - A.z).express(N).simplify() == sqrt(3)*N.x
|
447 |
+
assert _simplify_matrix(A.dcm(N)) == Matrix([
|
448 |
+
[sqrt(3)/3, -sqrt(6)*sin(q + pi/4)/3,
|
449 |
+
sqrt(6)*cos(q + pi/4)/3],
|
450 |
+
[sqrt(3)/3, sqrt(6)*cos(q + pi/12)/3,
|
451 |
+
sqrt(6)*sin(q + pi/12)/3],
|
452 |
+
[-sqrt(3)/3, sqrt(6)*cos(q + 5*pi/12)/3,
|
453 |
+
sqrt(6)*sin(q + 5*pi/12)/3]])
|
454 |
+
assert A.ang_vel_in(N) == u*N.x
|
455 |
+
assert A.ang_vel_in(N).express(A).simplify() == (u*A.x + u*A.y -
|
456 |
+
u*A.z)/sqrt(3)
|
457 |
+
assert A.ang_vel_in(N).magnitude() == sqrt(u**2)
|
458 |
+
angle = A.ang_vel_in(N).angle_between(A.x + A.y-A.z)
|
459 |
+
assert angle.xreplace({u: 1}) == 0
|
460 |
+
assert C.masscenter.vel(N).simplify() == (u*A.y + u*A.z)/sqrt(3)
|
461 |
+
assert C.masscenter.pos_from(P.masscenter) == N.x - A.x
|
462 |
+
assert (C.masscenter.pos_from(P.masscenter).express(N).simplify() ==
|
463 |
+
(1 - sqrt(3)/3)*N.x + sqrt(6)*sin(q + pi/4)/3*N.y -
|
464 |
+
sqrt(6)*cos(q + pi/4)/3*N.z)
|
465 |
+
assert (C.masscenter.vel(N).express(N).simplify() ==
|
466 |
+
sqrt(6)*u*cos(q + pi/4)/3*N.y +
|
467 |
+
sqrt(6)*u*sin(q + pi/4)/3*N.z)
|
468 |
+
assert C.masscenter.vel(N).angle_between(A.x) == pi/2
|
469 |
+
|
470 |
+
N, A, P, C = _generate_body()
|
471 |
+
m, n = symbols('m n')
|
472 |
+
PinJoint('J', P, C, parent_point=m * N.x, child_point=n * A.x,
|
473 |
+
child_interframe=A.x + A.y - A.z,
|
474 |
+
parent_interframe=N.x - N.y + N.z)
|
475 |
+
angle = (N.x - N.y + N.z).angle_between(A.x + A.y - A.z)
|
476 |
+
assert expand_mul(angle) == 0 # Axis are aligned
|
477 |
+
assert ((A.x-A.y+A.z).express(N).simplify() ==
|
478 |
+
(-4*cos(q)/3 - S(1)/3)*N.x + (S(1)/3 - 4*sin(q + pi/6)/3)*N.y +
|
479 |
+
(4*cos(q + pi/3)/3 - S(1)/3)*N.z)
|
480 |
+
assert _simplify_matrix(A.dcm(N)) == Matrix([
|
481 |
+
[S(1)/3 - 2*cos(q)/3, -2*sin(q + pi/6)/3 - S(1)/3,
|
482 |
+
2*cos(q + pi/3)/3 + S(1)/3],
|
483 |
+
[2*cos(q + pi/3)/3 + S(1)/3, 2*cos(q)/3 - S(1)/3,
|
484 |
+
2*sin(q + pi/6)/3 + S(1)/3],
|
485 |
+
[-2*sin(q + pi/6)/3 - S(1)/3, 2*cos(q + pi/3)/3 + S(1)/3,
|
486 |
+
2*cos(q)/3 - S(1)/3]])
|
487 |
+
assert A.ang_vel_in(N) == (u*N.x - u*N.y + u*N.z)/sqrt(3)
|
488 |
+
assert A.ang_vel_in(N).express(A).simplify() == (u*A.x + u*A.y -
|
489 |
+
u*A.z)/sqrt(3)
|
490 |
+
assert A.ang_vel_in(N).magnitude() == sqrt(u**2)
|
491 |
+
angle = A.ang_vel_in(N).angle_between(A.x+A.y-A.z)
|
492 |
+
assert angle.xreplace({u: 1}) == 0
|
493 |
+
assert (C.masscenter.vel(N).simplify() ==
|
494 |
+
sqrt(3)*n*u/3*A.y + sqrt(3)*n*u/3*A.z)
|
495 |
+
assert C.masscenter.pos_from(P.masscenter) == m*N.x - n*A.x
|
496 |
+
assert (C.masscenter.pos_from(P.masscenter).express(N).simplify() ==
|
497 |
+
(m + n*(2*cos(q) - 1)/3)*N.x + n*(2*sin(q + pi/6) +
|
498 |
+
1)/3*N.y - n*(2*cos(q + pi/3) + 1)/3*N.z)
|
499 |
+
assert (C.masscenter.vel(N).express(N).simplify() ==
|
500 |
+
- 2*n*u*sin(q)/3*N.x + 2*n*u*cos(q + pi/6)/3*N.y +
|
501 |
+
2*n*u*sin(q + pi/3)/3*N.z)
|
502 |
+
assert C.masscenter.vel(N).dot(N.x - N.y + N.z).simplify() == 0
|
503 |
+
|
504 |
+
|
505 |
+
def test_create_aligned_frame_pi():
|
506 |
+
N, A, P, C = _generate_body()
|
507 |
+
f = Joint._create_aligned_interframe(P, -P.x, P.x)
|
508 |
+
assert f.z == P.z
|
509 |
+
f = Joint._create_aligned_interframe(P, -P.y, P.y)
|
510 |
+
assert f.x == P.x
|
511 |
+
f = Joint._create_aligned_interframe(P, -P.z, P.z)
|
512 |
+
assert f.y == P.y
|
513 |
+
f = Joint._create_aligned_interframe(P, -P.x - P.y, P.x + P.y)
|
514 |
+
assert f.z == P.z
|
515 |
+
f = Joint._create_aligned_interframe(P, -P.y - P.z, P.y + P.z)
|
516 |
+
assert f.x == P.x
|
517 |
+
f = Joint._create_aligned_interframe(P, -P.x - P.z, P.x + P.z)
|
518 |
+
assert f.y == P.y
|
519 |
+
f = Joint._create_aligned_interframe(P, -P.x - P.y - P.z, P.x + P.y + P.z)
|
520 |
+
assert f.y - f.z == P.y - P.z
|
521 |
+
|
522 |
+
|
523 |
+
def test_pin_joint_axis():
|
524 |
+
q, u = dynamicsymbols('q u')
|
525 |
+
# Test default joint axis
|
526 |
+
N, A, P, C, Pint, Cint = _generate_body(True)
|
527 |
+
J = PinJoint('J', P, C, q, u, parent_interframe=Pint, child_interframe=Cint)
|
528 |
+
assert J.joint_axis == Pint.x
|
529 |
+
# Test for the same joint axis expressed in different frames
|
530 |
+
N_R_A = Matrix([[0, sin(q), cos(q)],
|
531 |
+
[0, -cos(q), sin(q)],
|
532 |
+
[1, 0, 0]])
|
533 |
+
N, A, P, C, Pint, Cint = _generate_body(True)
|
534 |
+
PinJoint('J', P, C, q, u, parent_interframe=Pint, child_interframe=Cint,
|
535 |
+
joint_axis=N.z)
|
536 |
+
assert N.dcm(A) == N_R_A
|
537 |
+
N, A, P, C, Pint, Cint = _generate_body(True)
|
538 |
+
PinJoint('J', P, C, q, u, parent_interframe=Pint, child_interframe=Cint,
|
539 |
+
joint_axis=-Pint.z)
|
540 |
+
assert N.dcm(A) == N_R_A
|
541 |
+
# Test time varying joint axis
|
542 |
+
N, A, P, C, Pint, Cint = _generate_body(True)
|
543 |
+
raises(ValueError, lambda: PinJoint('J', P, C, joint_axis=q * N.z))
|
544 |
+
|
545 |
+
|
546 |
+
def test_locate_joint_pos():
|
547 |
+
# Test Vector and default
|
548 |
+
N, A, P, C = _generate_body()
|
549 |
+
joint = PinJoint('J', P, C, parent_point=N.y + N.z)
|
550 |
+
assert joint.parent_point.name == 'J_P_joint'
|
551 |
+
assert joint.parent_point.pos_from(P.masscenter) == N.y + N.z
|
552 |
+
assert joint.child_point == C.masscenter
|
553 |
+
# Test Point objects
|
554 |
+
N, A, P, C = _generate_body()
|
555 |
+
parent_point = P.masscenter.locatenew('p', N.y + N.z)
|
556 |
+
joint = PinJoint('J', P, C, parent_point=parent_point,
|
557 |
+
child_point=C.masscenter)
|
558 |
+
assert joint.parent_point == parent_point
|
559 |
+
assert joint.child_point == C.masscenter
|
560 |
+
# Check invalid type
|
561 |
+
N, A, P, C = _generate_body()
|
562 |
+
raises(TypeError,
|
563 |
+
lambda: PinJoint('J', P, C, parent_point=N.x.to_matrix(N)))
|
564 |
+
# Test time varying positions
|
565 |
+
q = dynamicsymbols('q')
|
566 |
+
N, A, P, C = _generate_body()
|
567 |
+
raises(ValueError, lambda: PinJoint('J', P, C, parent_point=q * N.x))
|
568 |
+
N, A, P, C = _generate_body()
|
569 |
+
child_point = C.masscenter.locatenew('p', q * A.y)
|
570 |
+
raises(ValueError, lambda: PinJoint('J', P, C, child_point=child_point))
|
571 |
+
# Test undefined position
|
572 |
+
child_point = Point('p')
|
573 |
+
raises(ValueError, lambda: PinJoint('J', P, C, child_point=child_point))
|
574 |
+
|
575 |
+
|
576 |
+
def test_locate_joint_frame():
|
577 |
+
# Test rotated frame and default
|
578 |
+
N, A, P, C = _generate_body()
|
579 |
+
parent_interframe = ReferenceFrame('int_frame')
|
580 |
+
parent_interframe.orient_axis(N, N.z, 1)
|
581 |
+
joint = PinJoint('J', P, C, parent_interframe=parent_interframe)
|
582 |
+
assert joint.parent_interframe == parent_interframe
|
583 |
+
assert joint.parent_interframe.ang_vel_in(N) == 0
|
584 |
+
assert joint.child_interframe == A
|
585 |
+
# Test time varying orientations
|
586 |
+
q = dynamicsymbols('q')
|
587 |
+
N, A, P, C = _generate_body()
|
588 |
+
parent_interframe = ReferenceFrame('int_frame')
|
589 |
+
parent_interframe.orient_axis(N, N.z, q)
|
590 |
+
raises(ValueError,
|
591 |
+
lambda: PinJoint('J', P, C, parent_interframe=parent_interframe))
|
592 |
+
# Test undefined frame
|
593 |
+
N, A, P, C = _generate_body()
|
594 |
+
child_interframe = ReferenceFrame('int_frame')
|
595 |
+
child_interframe.orient_axis(N, N.z, 1) # Defined with respect to parent
|
596 |
+
raises(ValueError,
|
597 |
+
lambda: PinJoint('J', P, C, child_interframe=child_interframe))
|
598 |
+
|
599 |
+
|
600 |
+
def test_sliding_joint():
|
601 |
+
_, _, P, C = _generate_body()
|
602 |
+
q, u = dynamicsymbols('q_S, u_S')
|
603 |
+
S = PrismaticJoint('S', P, C)
|
604 |
+
assert S.name == 'S'
|
605 |
+
assert S.parent == P
|
606 |
+
assert S.child == C
|
607 |
+
assert S.coordinates == Matrix([q])
|
608 |
+
assert S.speeds == Matrix([u])
|
609 |
+
assert S.kdes == Matrix([u - q.diff(t)])
|
610 |
+
assert S.joint_axis == P.frame.x
|
611 |
+
assert S.child_point.pos_from(C.masscenter) == Vector(0)
|
612 |
+
assert S.parent_point.pos_from(P.masscenter) == Vector(0)
|
613 |
+
assert S.parent_point.pos_from(S.child_point) == - q * P.frame.x
|
614 |
+
assert P.masscenter.pos_from(C.masscenter) == - q * P.frame.x
|
615 |
+
assert C.masscenter.vel(P.frame) == u * P.frame.x
|
616 |
+
assert P.ang_vel_in(C) == 0
|
617 |
+
assert C.ang_vel_in(P) == 0
|
618 |
+
assert S.__str__() == 'PrismaticJoint: S parent: P child: C'
|
619 |
+
|
620 |
+
N, A, P, C = _generate_body()
|
621 |
+
l, m = symbols('l m')
|
622 |
+
Pint = ReferenceFrame('P_int')
|
623 |
+
Pint.orient_axis(P.frame, P.y, pi / 2)
|
624 |
+
S = PrismaticJoint('S', P, C, parent_point=l * P.frame.x,
|
625 |
+
child_point=m * C.frame.y, joint_axis=P.frame.z,
|
626 |
+
parent_interframe=Pint)
|
627 |
+
|
628 |
+
assert S.joint_axis == P.frame.z
|
629 |
+
assert S.child_point.pos_from(C.masscenter) == m * C.frame.y
|
630 |
+
assert S.parent_point.pos_from(P.masscenter) == l * P.frame.x
|
631 |
+
assert S.parent_point.pos_from(S.child_point) == - q * P.frame.z
|
632 |
+
assert P.masscenter.pos_from(C.masscenter) == - l*N.x - q*N.z + m*A.y
|
633 |
+
assert C.masscenter.vel(P.frame) == u * P.frame.z
|
634 |
+
assert P.masscenter.vel(Pint) == Vector(0)
|
635 |
+
assert C.ang_vel_in(P) == 0
|
636 |
+
assert P.ang_vel_in(C) == 0
|
637 |
+
|
638 |
+
_, _, P, C = _generate_body()
|
639 |
+
Pint = ReferenceFrame('P_int')
|
640 |
+
Pint.orient_axis(P.frame, P.y, pi / 2)
|
641 |
+
S = PrismaticJoint('S', P, C, parent_point=l * P.frame.z,
|
642 |
+
child_point=m * C.frame.x, joint_axis=P.frame.z,
|
643 |
+
parent_interframe=Pint)
|
644 |
+
assert S.joint_axis == P.frame.z
|
645 |
+
assert S.child_point.pos_from(C.masscenter) == m * C.frame.x
|
646 |
+
assert S.parent_point.pos_from(P.masscenter) == l * P.frame.z
|
647 |
+
assert S.parent_point.pos_from(S.child_point) == - q * P.frame.z
|
648 |
+
assert P.masscenter.pos_from(C.masscenter) == (-l - q)*P.frame.z + m*C.frame.x
|
649 |
+
assert C.masscenter.vel(P.frame) == u * P.frame.z
|
650 |
+
assert C.ang_vel_in(P) == 0
|
651 |
+
assert P.ang_vel_in(C) == 0
|
652 |
+
|
653 |
+
|
654 |
+
def test_sliding_joint_arbitrary_axis():
|
655 |
+
q, u = dynamicsymbols('q_S, u_S')
|
656 |
+
|
657 |
+
N, A, P, C = _generate_body()
|
658 |
+
PrismaticJoint('S', P, C, child_interframe=-A.x)
|
659 |
+
|
660 |
+
assert (-A.x).angle_between(N.x) == 0
|
661 |
+
assert -A.x.express(N) == N.x
|
662 |
+
assert A.dcm(N) == Matrix([[-1, 0, 0], [0, -1, 0], [0, 0, 1]])
|
663 |
+
assert C.masscenter.pos_from(P.masscenter) == q * N.x
|
664 |
+
assert C.masscenter.pos_from(P.masscenter).express(A).simplify() == -q * A.x
|
665 |
+
assert C.masscenter.vel(N) == u * N.x
|
666 |
+
assert C.masscenter.vel(N).express(A) == -u * A.x
|
667 |
+
assert A.ang_vel_in(N) == 0
|
668 |
+
assert N.ang_vel_in(A) == 0
|
669 |
+
|
670 |
+
#When axes are different and parent joint is at masscenter but child joint is at a unit vector from
|
671 |
+
#child masscenter.
|
672 |
+
N, A, P, C = _generate_body()
|
673 |
+
PrismaticJoint('S', P, C, child_interframe=A.y, child_point=A.x)
|
674 |
+
|
675 |
+
assert A.y.angle_between(N.x) == 0 #Axis are aligned
|
676 |
+
assert A.y.express(N) == N.x
|
677 |
+
assert A.dcm(N) == Matrix([[0, -1, 0], [1, 0, 0], [0, 0, 1]])
|
678 |
+
assert C.masscenter.vel(N) == u * N.x
|
679 |
+
assert C.masscenter.vel(N).express(A) == u * A.y
|
680 |
+
assert C.masscenter.pos_from(P.masscenter) == q*N.x - A.x
|
681 |
+
assert C.masscenter.pos_from(P.masscenter).express(N).simplify() == q*N.x + N.y
|
682 |
+
assert A.ang_vel_in(N) == 0
|
683 |
+
assert N.ang_vel_in(A) == 0
|
684 |
+
|
685 |
+
#Similar to previous case but wrt parent body
|
686 |
+
N, A, P, C = _generate_body()
|
687 |
+
PrismaticJoint('S', P, C, parent_interframe=N.y, parent_point=N.x)
|
688 |
+
|
689 |
+
assert N.y.angle_between(A.x) == 0 #Axis are aligned
|
690 |
+
assert N.y.express(A) == A.x
|
691 |
+
assert A.dcm(N) == Matrix([[0, 1, 0], [-1, 0, 0], [0, 0, 1]])
|
692 |
+
assert C.masscenter.vel(N) == u * N.y
|
693 |
+
assert C.masscenter.vel(N).express(A) == u * A.x
|
694 |
+
assert C.masscenter.pos_from(P.masscenter) == N.x + q*N.y
|
695 |
+
assert A.ang_vel_in(N) == 0
|
696 |
+
assert N.ang_vel_in(A) == 0
|
697 |
+
|
698 |
+
#Both joint pos is defined but different axes
|
699 |
+
N, A, P, C = _generate_body()
|
700 |
+
PrismaticJoint('S', P, C, parent_point=N.x, child_point=A.x,
|
701 |
+
child_interframe=A.x + A.y)
|
702 |
+
assert N.x.angle_between(A.x + A.y) == 0 #Axis are aligned
|
703 |
+
assert (A.x + A.y).express(N) == sqrt(2)*N.x
|
704 |
+
assert A.dcm(N) == Matrix([[sqrt(2)/2, -sqrt(2)/2, 0], [sqrt(2)/2, sqrt(2)/2, 0], [0, 0, 1]])
|
705 |
+
assert C.masscenter.pos_from(P.masscenter) == (q + 1)*N.x - A.x
|
706 |
+
assert C.masscenter.pos_from(P.masscenter).express(N) == (q - sqrt(2)/2 + 1)*N.x + sqrt(2)/2*N.y
|
707 |
+
assert C.masscenter.vel(N).express(A) == u * (A.x + A.y)/sqrt(2)
|
708 |
+
assert C.masscenter.vel(N) == u*N.x
|
709 |
+
assert A.ang_vel_in(N) == 0
|
710 |
+
assert N.ang_vel_in(A) == 0
|
711 |
+
|
712 |
+
N, A, P, C = _generate_body()
|
713 |
+
PrismaticJoint('S', P, C, parent_point=N.x, child_point=A.x,
|
714 |
+
child_interframe=A.x + A.y - A.z)
|
715 |
+
assert N.x.angle_between(A.x + A.y - A.z) == 0 #Axis are aligned
|
716 |
+
assert (A.x + A.y - A.z).express(N) == sqrt(3)*N.x
|
717 |
+
assert _simplify_matrix(A.dcm(N)) == Matrix([[sqrt(3)/3, -sqrt(3)/3, sqrt(3)/3],
|
718 |
+
[sqrt(3)/3, sqrt(3)/6 + S(1)/2, S(1)/2 - sqrt(3)/6],
|
719 |
+
[-sqrt(3)/3, S(1)/2 - sqrt(3)/6, sqrt(3)/6 + S(1)/2]])
|
720 |
+
assert C.masscenter.pos_from(P.masscenter) == (q + 1)*N.x - A.x
|
721 |
+
assert C.masscenter.pos_from(P.masscenter).express(N) == \
|
722 |
+
(q - sqrt(3)/3 + 1)*N.x + sqrt(3)/3*N.y - sqrt(3)/3*N.z
|
723 |
+
assert C.masscenter.vel(N) == u*N.x
|
724 |
+
assert C.masscenter.vel(N).express(A) == sqrt(3)*u/3*A.x + sqrt(3)*u/3*A.y - sqrt(3)*u/3*A.z
|
725 |
+
assert A.ang_vel_in(N) == 0
|
726 |
+
assert N.ang_vel_in(A) == 0
|
727 |
+
|
728 |
+
N, A, P, C = _generate_body()
|
729 |
+
m, n = symbols('m n')
|
730 |
+
PrismaticJoint('S', P, C, parent_point=m*N.x, child_point=n*A.x,
|
731 |
+
child_interframe=A.x + A.y - A.z,
|
732 |
+
parent_interframe=N.x - N.y + N.z)
|
733 |
+
# 0 angle means that the axis are aligned
|
734 |
+
assert (N.x-N.y+N.z).angle_between(A.x+A.y-A.z).simplify() == 0
|
735 |
+
assert (A.x+A.y-A.z).express(N) == N.x - N.y + N.z
|
736 |
+
assert _simplify_matrix(A.dcm(N)) == Matrix([[-S(1)/3, -S(2)/3, S(2)/3],
|
737 |
+
[S(2)/3, S(1)/3, S(2)/3],
|
738 |
+
[-S(2)/3, S(2)/3, S(1)/3]])
|
739 |
+
assert C.masscenter.pos_from(P.masscenter) == \
|
740 |
+
(m + sqrt(3)*q/3)*N.x - sqrt(3)*q/3*N.y + sqrt(3)*q/3*N.z - n*A.x
|
741 |
+
assert C.masscenter.pos_from(P.masscenter).express(N) == \
|
742 |
+
(m + n/3 + sqrt(3)*q/3)*N.x + (2*n/3 - sqrt(3)*q/3)*N.y + (-2*n/3 + sqrt(3)*q/3)*N.z
|
743 |
+
assert C.masscenter.vel(N) == sqrt(3)*u/3*N.x - sqrt(3)*u/3*N.y + sqrt(3)*u/3*N.z
|
744 |
+
assert C.masscenter.vel(N).express(A) == sqrt(3)*u/3*A.x + sqrt(3)*u/3*A.y - sqrt(3)*u/3*A.z
|
745 |
+
assert A.ang_vel_in(N) == 0
|
746 |
+
assert N.ang_vel_in(A) == 0
|
747 |
+
|
748 |
+
|
749 |
+
def test_cylindrical_joint():
|
750 |
+
N, A, P, C = _generate_body()
|
751 |
+
q0_def, q1_def, u0_def, u1_def = dynamicsymbols('q0:2_J, u0:2_J')
|
752 |
+
Cj = CylindricalJoint('J', P, C)
|
753 |
+
assert Cj.name == 'J'
|
754 |
+
assert Cj.parent == P
|
755 |
+
assert Cj.child == C
|
756 |
+
assert Cj.coordinates == Matrix([q0_def, q1_def])
|
757 |
+
assert Cj.speeds == Matrix([u0_def, u1_def])
|
758 |
+
assert Cj.rotation_coordinate == q0_def
|
759 |
+
assert Cj.translation_coordinate == q1_def
|
760 |
+
assert Cj.rotation_speed == u0_def
|
761 |
+
assert Cj.translation_speed == u1_def
|
762 |
+
assert Cj.kdes == Matrix([u0_def - q0_def.diff(t), u1_def - q1_def.diff(t)])
|
763 |
+
assert Cj.joint_axis == N.x
|
764 |
+
assert Cj.child_point.pos_from(C.masscenter) == Vector(0)
|
765 |
+
assert Cj.parent_point.pos_from(P.masscenter) == Vector(0)
|
766 |
+
assert Cj.parent_point.pos_from(Cj._child_point) == -q1_def * N.x
|
767 |
+
assert C.masscenter.pos_from(P.masscenter) == q1_def * N.x
|
768 |
+
assert Cj.child_point.vel(N) == u1_def * N.x
|
769 |
+
assert A.ang_vel_in(N) == u0_def * N.x
|
770 |
+
assert Cj.parent_interframe == N
|
771 |
+
assert Cj.child_interframe == A
|
772 |
+
assert Cj.__str__() == 'CylindricalJoint: J parent: P child: C'
|
773 |
+
|
774 |
+
q0, q1, u0, u1 = dynamicsymbols('q0:2, u0:2')
|
775 |
+
l, m = symbols('l, m')
|
776 |
+
N, A, P, C, Pint, Cint = _generate_body(True)
|
777 |
+
Cj = CylindricalJoint('J', P, C, rotation_coordinate=q0, rotation_speed=u0,
|
778 |
+
translation_speed=u1, parent_point=m * N.x,
|
779 |
+
child_point=l * A.y, parent_interframe=Pint,
|
780 |
+
child_interframe=Cint, joint_axis=2 * N.z)
|
781 |
+
assert Cj.coordinates == Matrix([q0, q1_def])
|
782 |
+
assert Cj.speeds == Matrix([u0, u1])
|
783 |
+
assert Cj.rotation_coordinate == q0
|
784 |
+
assert Cj.translation_coordinate == q1_def
|
785 |
+
assert Cj.rotation_speed == u0
|
786 |
+
assert Cj.translation_speed == u1
|
787 |
+
assert Cj.kdes == Matrix([u0 - q0.diff(t), u1 - q1_def.diff(t)])
|
788 |
+
assert Cj.joint_axis == 2 * N.z
|
789 |
+
assert Cj.child_point.pos_from(C.masscenter) == l * A.y
|
790 |
+
assert Cj.parent_point.pos_from(P.masscenter) == m * N.x
|
791 |
+
assert Cj.parent_point.pos_from(Cj._child_point) == -q1_def * N.z
|
792 |
+
assert C.masscenter.pos_from(
|
793 |
+
P.masscenter) == m * N.x + q1_def * N.z - l * A.y
|
794 |
+
assert C.masscenter.vel(N) == u1 * N.z - u0 * l * A.z
|
795 |
+
assert A.ang_vel_in(N) == u0 * N.z
|
796 |
+
|
797 |
+
|
798 |
+
def test_planar_joint():
|
799 |
+
N, A, P, C = _generate_body()
|
800 |
+
q0_def, q1_def, q2_def = dynamicsymbols('q0:3_J')
|
801 |
+
u0_def, u1_def, u2_def = dynamicsymbols('u0:3_J')
|
802 |
+
Cj = PlanarJoint('J', P, C)
|
803 |
+
assert Cj.name == 'J'
|
804 |
+
assert Cj.parent == P
|
805 |
+
assert Cj.child == C
|
806 |
+
assert Cj.coordinates == Matrix([q0_def, q1_def, q2_def])
|
807 |
+
assert Cj.speeds == Matrix([u0_def, u1_def, u2_def])
|
808 |
+
assert Cj.rotation_coordinate == q0_def
|
809 |
+
assert Cj.planar_coordinates == Matrix([q1_def, q2_def])
|
810 |
+
assert Cj.rotation_speed == u0_def
|
811 |
+
assert Cj.planar_speeds == Matrix([u1_def, u2_def])
|
812 |
+
assert Cj.kdes == Matrix([u0_def - q0_def.diff(t), u1_def - q1_def.diff(t),
|
813 |
+
u2_def - q2_def.diff(t)])
|
814 |
+
assert Cj.rotation_axis == N.x
|
815 |
+
assert Cj.planar_vectors == [N.y, N.z]
|
816 |
+
assert Cj.child_point.pos_from(C.masscenter) == Vector(0)
|
817 |
+
assert Cj.parent_point.pos_from(P.masscenter) == Vector(0)
|
818 |
+
r_P_C = q1_def * N.y + q2_def * N.z
|
819 |
+
assert Cj.parent_point.pos_from(Cj.child_point) == -r_P_C
|
820 |
+
assert C.masscenter.pos_from(P.masscenter) == r_P_C
|
821 |
+
assert Cj.child_point.vel(N) == u1_def * N.y + u2_def * N.z
|
822 |
+
assert A.ang_vel_in(N) == u0_def * N.x
|
823 |
+
assert Cj.parent_interframe == N
|
824 |
+
assert Cj.child_interframe == A
|
825 |
+
assert Cj.__str__() == 'PlanarJoint: J parent: P child: C'
|
826 |
+
|
827 |
+
q0, q1, q2, u0, u1, u2 = dynamicsymbols('q0:3, u0:3')
|
828 |
+
l, m = symbols('l, m')
|
829 |
+
N, A, P, C, Pint, Cint = _generate_body(True)
|
830 |
+
Cj = PlanarJoint('J', P, C, rotation_coordinate=q0,
|
831 |
+
planar_coordinates=[q1, q2], planar_speeds=[u1, u2],
|
832 |
+
parent_point=m * N.x, child_point=l * A.y,
|
833 |
+
parent_interframe=Pint, child_interframe=Cint)
|
834 |
+
assert Cj.coordinates == Matrix([q0, q1, q2])
|
835 |
+
assert Cj.speeds == Matrix([u0_def, u1, u2])
|
836 |
+
assert Cj.rotation_coordinate == q0
|
837 |
+
assert Cj.planar_coordinates == Matrix([q1, q2])
|
838 |
+
assert Cj.rotation_speed == u0_def
|
839 |
+
assert Cj.planar_speeds == Matrix([u1, u2])
|
840 |
+
assert Cj.kdes == Matrix([u0_def - q0.diff(t), u1 - q1.diff(t),
|
841 |
+
u2 - q2.diff(t)])
|
842 |
+
assert Cj.rotation_axis == Pint.x
|
843 |
+
assert Cj.planar_vectors == [Pint.y, Pint.z]
|
844 |
+
assert Cj.child_point.pos_from(C.masscenter) == l * A.y
|
845 |
+
assert Cj.parent_point.pos_from(P.masscenter) == m * N.x
|
846 |
+
assert Cj.parent_point.pos_from(Cj.child_point) == q1 * N.y + q2 * N.z
|
847 |
+
assert C.masscenter.pos_from(
|
848 |
+
P.masscenter) == m * N.x - q1 * N.y - q2 * N.z - l * A.y
|
849 |
+
assert C.masscenter.vel(N) == -u1 * N.y - u2 * N.z + u0_def * l * A.x
|
850 |
+
assert A.ang_vel_in(N) == u0_def * N.x
|
851 |
+
|
852 |
+
|
853 |
+
def test_planar_joint_advanced():
|
854 |
+
# Tests whether someone is able to just specify two normals, which will form
|
855 |
+
# the rotation axis seen from the parent and child body.
|
856 |
+
# This specific example is a block on a slope, which has that same slope of
|
857 |
+
# 30 degrees, so in the zero configuration the frames of the parent and
|
858 |
+
# child are actually aligned.
|
859 |
+
q0, q1, q2, u0, u1, u2 = dynamicsymbols('q0:3, u0:3')
|
860 |
+
l1, l2 = symbols('l1:3')
|
861 |
+
N, A, P, C = _generate_body()
|
862 |
+
J = PlanarJoint('J', P, C, q0, [q1, q2], u0, [u1, u2],
|
863 |
+
parent_point=l1 * N.z,
|
864 |
+
child_point=-l2 * C.z,
|
865 |
+
parent_interframe=N.z + N.y / sqrt(3),
|
866 |
+
child_interframe=A.z + A.y / sqrt(3))
|
867 |
+
assert J.rotation_axis.express(N) == (N.z + N.y / sqrt(3)).normalize()
|
868 |
+
assert J.rotation_axis.express(A) == (A.z + A.y / sqrt(3)).normalize()
|
869 |
+
assert J.rotation_axis.angle_between(N.z) == pi / 6
|
870 |
+
assert N.dcm(A).xreplace({q0: 0, q1: 0, q2: 0}) == eye(3)
|
871 |
+
N_R_A = Matrix([
|
872 |
+
[cos(q0), -sqrt(3) * sin(q0) / 2, sin(q0) / 2],
|
873 |
+
[sqrt(3) * sin(q0) / 2, 3 * cos(q0) / 4 + 1 / 4,
|
874 |
+
sqrt(3) * (1 - cos(q0)) / 4],
|
875 |
+
[-sin(q0) / 2, sqrt(3) * (1 - cos(q0)) / 4, cos(q0) / 4 + 3 / 4]])
|
876 |
+
# N.dcm(A) == N_R_A did not work
|
877 |
+
assert _simplify_matrix(N.dcm(A) - N_R_A) == zeros(3)
|
878 |
+
|
879 |
+
|
880 |
+
def test_spherical_joint():
|
881 |
+
N, A, P, C = _generate_body()
|
882 |
+
q0, q1, q2, u0, u1, u2 = dynamicsymbols('q0:3_S, u0:3_S')
|
883 |
+
S = SphericalJoint('S', P, C)
|
884 |
+
assert S.name == 'S'
|
885 |
+
assert S.parent == P
|
886 |
+
assert S.child == C
|
887 |
+
assert S.coordinates == Matrix([q0, q1, q2])
|
888 |
+
assert S.speeds == Matrix([u0, u1, u2])
|
889 |
+
assert S.kdes == Matrix([u0 - q0.diff(t), u1 - q1.diff(t), u2 - q2.diff(t)])
|
890 |
+
assert S.child_point.pos_from(C.masscenter) == Vector(0)
|
891 |
+
assert S.parent_point.pos_from(P.masscenter) == Vector(0)
|
892 |
+
assert S.parent_point.pos_from(S.child_point) == Vector(0)
|
893 |
+
assert P.masscenter.pos_from(C.masscenter) == Vector(0)
|
894 |
+
assert C.masscenter.vel(N) == Vector(0)
|
895 |
+
assert P.ang_vel_in(C) == (-u0 * cos(q1) * cos(q2) - u1 * sin(q2)) * A.x + (
|
896 |
+
u0 * sin(q2) * cos(q1) - u1 * cos(q2)) * A.y + (
|
897 |
+
-u0 * sin(q1) - u2) * A.z
|
898 |
+
assert C.ang_vel_in(P) == (u0 * cos(q1) * cos(q2) + u1 * sin(q2)) * A.x + (
|
899 |
+
-u0 * sin(q2) * cos(q1) + u1 * cos(q2)) * A.y + (
|
900 |
+
u0 * sin(q1) + u2) * A.z
|
901 |
+
assert S.__str__() == 'SphericalJoint: S parent: P child: C'
|
902 |
+
assert S._rot_type == 'BODY'
|
903 |
+
assert S._rot_order == 123
|
904 |
+
assert S._amounts is None
|
905 |
+
|
906 |
+
|
907 |
+
def test_spherical_joint_speeds_as_derivative_terms():
|
908 |
+
# This tests checks whether the system remains valid if the user chooses to
|
909 |
+
# pass the derivative of the generalized coordinates as generalized speeds
|
910 |
+
q0, q1, q2 = dynamicsymbols('q0:3')
|
911 |
+
u0, u1, u2 = dynamicsymbols('q0:3', 1)
|
912 |
+
N, A, P, C = _generate_body()
|
913 |
+
S = SphericalJoint('S', P, C, coordinates=[q0, q1, q2], speeds=[u0, u1, u2])
|
914 |
+
assert S.coordinates == Matrix([q0, q1, q2])
|
915 |
+
assert S.speeds == Matrix([u0, u1, u2])
|
916 |
+
assert S.kdes == Matrix([0, 0, 0])
|
917 |
+
assert P.ang_vel_in(C) == (-u0 * cos(q1) * cos(q2) - u1 * sin(q2)) * A.x + (
|
918 |
+
u0 * sin(q2) * cos(q1) - u1 * cos(q2)) * A.y + (
|
919 |
+
-u0 * sin(q1) - u2) * A.z
|
920 |
+
|
921 |
+
|
922 |
+
def test_spherical_joint_coords():
|
923 |
+
q0s, q1s, q2s, u0s, u1s, u2s = dynamicsymbols('q0:3_S, u0:3_S')
|
924 |
+
q0, q1, q2, q3, u0, u1, u2, u4 = dynamicsymbols('q0:4, u0:4')
|
925 |
+
# Test coordinates as list
|
926 |
+
N, A, P, C = _generate_body()
|
927 |
+
S = SphericalJoint('S', P, C, [q0, q1, q2], [u0, u1, u2])
|
928 |
+
assert S.coordinates == Matrix([q0, q1, q2])
|
929 |
+
assert S.speeds == Matrix([u0, u1, u2])
|
930 |
+
# Test coordinates as Matrix
|
931 |
+
N, A, P, C = _generate_body()
|
932 |
+
S = SphericalJoint('S', P, C, Matrix([q0, q1, q2]),
|
933 |
+
Matrix([u0, u1, u2]))
|
934 |
+
assert S.coordinates == Matrix([q0, q1, q2])
|
935 |
+
assert S.speeds == Matrix([u0, u1, u2])
|
936 |
+
# Test too few generalized coordinates
|
937 |
+
N, A, P, C = _generate_body()
|
938 |
+
raises(ValueError,
|
939 |
+
lambda: SphericalJoint('S', P, C, Matrix([q0, q1]), Matrix([u0])))
|
940 |
+
# Test too many generalized coordinates
|
941 |
+
raises(ValueError, lambda: SphericalJoint(
|
942 |
+
'S', P, C, Matrix([q0, q1, q2, q3]), Matrix([u0, u1, u2])))
|
943 |
+
raises(ValueError, lambda: SphericalJoint(
|
944 |
+
'S', P, C, Matrix([q0, q1, q2]), Matrix([u0, u1, u2, u4])))
|
945 |
+
|
946 |
+
|
947 |
+
def test_spherical_joint_orient_body():
|
948 |
+
q0, q1, q2, u0, u1, u2 = dynamicsymbols('q0:3, u0:3')
|
949 |
+
N_R_A = Matrix([
|
950 |
+
[-sin(q1), -sin(q2) * cos(q1), cos(q1) * cos(q2)],
|
951 |
+
[-sin(q0) * cos(q1), sin(q0) * sin(q1) * sin(q2) - cos(q0) * cos(q2),
|
952 |
+
-sin(q0) * sin(q1) * cos(q2) - sin(q2) * cos(q0)],
|
953 |
+
[cos(q0) * cos(q1), -sin(q0) * cos(q2) - sin(q1) * sin(q2) * cos(q0),
|
954 |
+
-sin(q0) * sin(q2) + sin(q1) * cos(q0) * cos(q2)]])
|
955 |
+
N_w_A = Matrix([[-u0 * sin(q1) - u2],
|
956 |
+
[-u0 * sin(q2) * cos(q1) + u1 * cos(q2)],
|
957 |
+
[u0 * cos(q1) * cos(q2) + u1 * sin(q2)]])
|
958 |
+
N_v_Co = Matrix([
|
959 |
+
[-sqrt(2) * (u0 * cos(q2 + pi / 4) * cos(q1) + u1 * sin(q2 + pi / 4))],
|
960 |
+
[-u0 * sin(q1) - u2], [-u0 * sin(q1) - u2]])
|
961 |
+
# Test default rot_type='BODY', rot_order=123
|
962 |
+
N, A, P, C, Pint, Cint = _generate_body(True)
|
963 |
+
S = SphericalJoint('S', P, C, coordinates=[q0, q1, q2], speeds=[u0, u1, u2],
|
964 |
+
parent_point=N.x + N.y, child_point=-A.y + A.z,
|
965 |
+
parent_interframe=Pint, child_interframe=Cint,
|
966 |
+
rot_type='body', rot_order=123)
|
967 |
+
assert S._rot_type.upper() == 'BODY'
|
968 |
+
assert S._rot_order == 123
|
969 |
+
assert _simplify_matrix(N.dcm(A) - N_R_A) == zeros(3)
|
970 |
+
assert A.ang_vel_in(N).to_matrix(A) == N_w_A
|
971 |
+
assert C.masscenter.vel(N).to_matrix(A) == N_v_Co
|
972 |
+
# Test change of amounts
|
973 |
+
N, A, P, C, Pint, Cint = _generate_body(True)
|
974 |
+
S = SphericalJoint('S', P, C, coordinates=[q0, q1, q2], speeds=[u0, u1, u2],
|
975 |
+
parent_point=N.x + N.y, child_point=-A.y + A.z,
|
976 |
+
parent_interframe=Pint, child_interframe=Cint,
|
977 |
+
rot_type='BODY', amounts=(q1, q0, q2), rot_order=123)
|
978 |
+
switch_order = lambda expr: expr.xreplace(
|
979 |
+
{q0: q1, q1: q0, q2: q2, u0: u1, u1: u0, u2: u2})
|
980 |
+
assert S._rot_type.upper() == 'BODY'
|
981 |
+
assert S._rot_order == 123
|
982 |
+
assert _simplify_matrix(N.dcm(A) - switch_order(N_R_A)) == zeros(3)
|
983 |
+
assert A.ang_vel_in(N).to_matrix(A) == switch_order(N_w_A)
|
984 |
+
assert C.masscenter.vel(N).to_matrix(A) == switch_order(N_v_Co)
|
985 |
+
# Test different rot_order
|
986 |
+
N, A, P, C, Pint, Cint = _generate_body(True)
|
987 |
+
S = SphericalJoint('S', P, C, coordinates=[q0, q1, q2], speeds=[u0, u1, u2],
|
988 |
+
parent_point=N.x + N.y, child_point=-A.y + A.z,
|
989 |
+
parent_interframe=Pint, child_interframe=Cint,
|
990 |
+
rot_type='BodY', rot_order='yxz')
|
991 |
+
assert S._rot_type.upper() == 'BODY'
|
992 |
+
assert S._rot_order == 'yxz'
|
993 |
+
assert _simplify_matrix(N.dcm(A) - Matrix([
|
994 |
+
[-sin(q0) * cos(q1), sin(q0) * sin(q1) * cos(q2) - sin(q2) * cos(q0),
|
995 |
+
sin(q0) * sin(q1) * sin(q2) + cos(q0) * cos(q2)],
|
996 |
+
[-sin(q1), -cos(q1) * cos(q2), -sin(q2) * cos(q1)],
|
997 |
+
[cos(q0) * cos(q1), -sin(q0) * sin(q2) - sin(q1) * cos(q0) * cos(q2),
|
998 |
+
sin(q0) * cos(q2) - sin(q1) * sin(q2) * cos(q0)]])) == zeros(3)
|
999 |
+
assert A.ang_vel_in(N).to_matrix(A) == Matrix([
|
1000 |
+
[u0 * sin(q1) - u2], [u0 * cos(q1) * cos(q2) - u1 * sin(q2)],
|
1001 |
+
[u0 * sin(q2) * cos(q1) + u1 * cos(q2)]])
|
1002 |
+
assert C.masscenter.vel(N).to_matrix(A) == Matrix([
|
1003 |
+
[-sqrt(2) * (u0 * sin(q2 + pi / 4) * cos(q1) + u1 * cos(q2 + pi / 4))],
|
1004 |
+
[u0 * sin(q1) - u2], [u0 * sin(q1) - u2]])
|
1005 |
+
|
1006 |
+
|
1007 |
+
def test_spherical_joint_orient_space():
|
1008 |
+
q0, q1, q2, u0, u1, u2 = dynamicsymbols('q0:3, u0:3')
|
1009 |
+
N_R_A = Matrix([
|
1010 |
+
[-sin(q0) * sin(q2) - sin(q1) * cos(q0) * cos(q2),
|
1011 |
+
sin(q0) * sin(q1) * cos(q2) - sin(q2) * cos(q0), cos(q1) * cos(q2)],
|
1012 |
+
[-sin(q0) * cos(q2) + sin(q1) * sin(q2) * cos(q0),
|
1013 |
+
-sin(q0) * sin(q1) * sin(q2) - cos(q0) * cos(q2), -sin(q2) * cos(q1)],
|
1014 |
+
[cos(q0) * cos(q1), -sin(q0) * cos(q1), sin(q1)]])
|
1015 |
+
N_w_A = Matrix([
|
1016 |
+
[u1 * sin(q0) - u2 * cos(q0) * cos(q1)],
|
1017 |
+
[u1 * cos(q0) + u2 * sin(q0) * cos(q1)], [u0 - u2 * sin(q1)]])
|
1018 |
+
N_v_Co = Matrix([
|
1019 |
+
[u0 - u2 * sin(q1)], [u0 - u2 * sin(q1)],
|
1020 |
+
[sqrt(2) * (-u1 * sin(q0 + pi / 4) + u2 * cos(q0 + pi / 4) * cos(q1))]])
|
1021 |
+
# Test default rot_type='BODY', rot_order=123
|
1022 |
+
N, A, P, C, Pint, Cint = _generate_body(True)
|
1023 |
+
S = SphericalJoint('S', P, C, coordinates=[q0, q1, q2], speeds=[u0, u1, u2],
|
1024 |
+
parent_point=N.x + N.z, child_point=-A.x + A.y,
|
1025 |
+
parent_interframe=Pint, child_interframe=Cint,
|
1026 |
+
rot_type='space', rot_order=123)
|
1027 |
+
assert S._rot_type.upper() == 'SPACE'
|
1028 |
+
assert S._rot_order == 123
|
1029 |
+
assert _simplify_matrix(N.dcm(A) - N_R_A) == zeros(3)
|
1030 |
+
assert _simplify_matrix(A.ang_vel_in(N).to_matrix(A)) == N_w_A
|
1031 |
+
assert _simplify_matrix(C.masscenter.vel(N).to_matrix(A)) == N_v_Co
|
1032 |
+
# Test change of amounts
|
1033 |
+
switch_order = lambda expr: expr.xreplace(
|
1034 |
+
{q0: q1, q1: q0, q2: q2, u0: u1, u1: u0, u2: u2})
|
1035 |
+
N, A, P, C, Pint, Cint = _generate_body(True)
|
1036 |
+
S = SphericalJoint('S', P, C, coordinates=[q0, q1, q2], speeds=[u0, u1, u2],
|
1037 |
+
parent_point=N.x + N.z, child_point=-A.x + A.y,
|
1038 |
+
parent_interframe=Pint, child_interframe=Cint,
|
1039 |
+
rot_type='SPACE', amounts=(q1, q0, q2), rot_order=123)
|
1040 |
+
assert S._rot_type.upper() == 'SPACE'
|
1041 |
+
assert S._rot_order == 123
|
1042 |
+
assert _simplify_matrix(N.dcm(A) - switch_order(N_R_A)) == zeros(3)
|
1043 |
+
assert _simplify_matrix(A.ang_vel_in(N).to_matrix(A)) == switch_order(N_w_A)
|
1044 |
+
assert _simplify_matrix(C.masscenter.vel(N).to_matrix(A)) == switch_order(N_v_Co)
|
1045 |
+
# Test different rot_order
|
1046 |
+
N, A, P, C, Pint, Cint = _generate_body(True)
|
1047 |
+
S = SphericalJoint('S', P, C, coordinates=[q0, q1, q2], speeds=[u0, u1, u2],
|
1048 |
+
parent_point=N.x + N.z, child_point=-A.x + A.y,
|
1049 |
+
parent_interframe=Pint, child_interframe=Cint,
|
1050 |
+
rot_type='SPaCe', rot_order='zxy')
|
1051 |
+
assert S._rot_type.upper() == 'SPACE'
|
1052 |
+
assert S._rot_order == 'zxy'
|
1053 |
+
assert _simplify_matrix(N.dcm(A) - Matrix([
|
1054 |
+
[-sin(q2) * cos(q1), -sin(q0) * cos(q2) + sin(q1) * sin(q2) * cos(q0),
|
1055 |
+
sin(q0) * sin(q1) * sin(q2) + cos(q0) * cos(q2)],
|
1056 |
+
[-sin(q1), -cos(q0) * cos(q1), -sin(q0) * cos(q1)],
|
1057 |
+
[cos(q1) * cos(q2), -sin(q0) * sin(q2) - sin(q1) * cos(q0) * cos(q2),
|
1058 |
+
-sin(q0) * sin(q1) * cos(q2) + sin(q2) * cos(q0)]]))
|
1059 |
+
assert _simplify_matrix(A.ang_vel_in(N).to_matrix(A) - Matrix([
|
1060 |
+
[-u0 + u2 * sin(q1)], [-u1 * sin(q0) + u2 * cos(q0) * cos(q1)],
|
1061 |
+
[u1 * cos(q0) + u2 * sin(q0) * cos(q1)]])) == zeros(3, 1)
|
1062 |
+
assert _simplify_matrix(C.masscenter.vel(N).to_matrix(A) - Matrix([
|
1063 |
+
[u1 * cos(q0) + u2 * sin(q0) * cos(q1)],
|
1064 |
+
[u1 * cos(q0) + u2 * sin(q0) * cos(q1)],
|
1065 |
+
[u0 + u1 * sin(q0) - u2 * sin(q1) -
|
1066 |
+
u2 * cos(q0) * cos(q1)]])) == zeros(3, 1)
|
1067 |
+
|
1068 |
+
|
1069 |
+
def test_weld_joint():
|
1070 |
+
_, _, P, C = _generate_body()
|
1071 |
+
W = WeldJoint('W', P, C)
|
1072 |
+
assert W.name == 'W'
|
1073 |
+
assert W.parent == P
|
1074 |
+
assert W.child == C
|
1075 |
+
assert W.coordinates == Matrix()
|
1076 |
+
assert W.speeds == Matrix()
|
1077 |
+
assert W.kdes == Matrix(1, 0, []).T
|
1078 |
+
assert P.dcm(C) == eye(3)
|
1079 |
+
assert W.child_point.pos_from(C.masscenter) == Vector(0)
|
1080 |
+
assert W.parent_point.pos_from(P.masscenter) == Vector(0)
|
1081 |
+
assert W.parent_point.pos_from(W.child_point) == Vector(0)
|
1082 |
+
assert P.masscenter.pos_from(C.masscenter) == Vector(0)
|
1083 |
+
assert C.masscenter.vel(P.frame) == Vector(0)
|
1084 |
+
assert P.ang_vel_in(C) == 0
|
1085 |
+
assert C.ang_vel_in(P) == 0
|
1086 |
+
assert W.__str__() == 'WeldJoint: W parent: P child: C'
|
1087 |
+
|
1088 |
+
N, A, P, C = _generate_body()
|
1089 |
+
l, m = symbols('l m')
|
1090 |
+
Pint = ReferenceFrame('P_int')
|
1091 |
+
Pint.orient_axis(P.frame, P.y, pi / 2)
|
1092 |
+
W = WeldJoint('W', P, C, parent_point=l * P.frame.x,
|
1093 |
+
child_point=m * C.frame.y, parent_interframe=Pint)
|
1094 |
+
|
1095 |
+
assert W.child_point.pos_from(C.masscenter) == m * C.frame.y
|
1096 |
+
assert W.parent_point.pos_from(P.masscenter) == l * P.frame.x
|
1097 |
+
assert W.parent_point.pos_from(W.child_point) == Vector(0)
|
1098 |
+
assert P.masscenter.pos_from(C.masscenter) == - l * N.x + m * A.y
|
1099 |
+
assert C.masscenter.vel(P.frame) == Vector(0)
|
1100 |
+
assert P.masscenter.vel(Pint) == Vector(0)
|
1101 |
+
assert C.ang_vel_in(P) == 0
|
1102 |
+
assert P.ang_vel_in(C) == 0
|
1103 |
+
assert P.x == A.z
|
1104 |
+
|
1105 |
+
JointsMethod(P, W) # Tests #10770
|
1106 |
+
|
1107 |
+
|
1108 |
+
def test_deprecated_parent_child_axis():
|
1109 |
+
q, u = dynamicsymbols('q_J, u_J')
|
1110 |
+
N, A, P, C = _generate_body()
|
1111 |
+
with warns_deprecated_sympy():
|
1112 |
+
PinJoint('J', P, C, child_axis=-A.x)
|
1113 |
+
assert (-A.x).angle_between(N.x) == 0
|
1114 |
+
assert -A.x.express(N) == N.x
|
1115 |
+
assert A.dcm(N) == Matrix([[-1, 0, 0],
|
1116 |
+
[0, -cos(q), -sin(q)],
|
1117 |
+
[0, -sin(q), cos(q)]])
|
1118 |
+
assert A.ang_vel_in(N) == u * N.x
|
1119 |
+
assert A.ang_vel_in(N).magnitude() == sqrt(u ** 2)
|
1120 |
+
|
1121 |
+
N, A, P, C = _generate_body()
|
1122 |
+
with warns_deprecated_sympy():
|
1123 |
+
PrismaticJoint('J', P, C, parent_axis=P.x + P.y)
|
1124 |
+
assert (A.x).angle_between(N.x + N.y) == 0
|
1125 |
+
assert A.x.express(N) == (N.x + N.y) / sqrt(2)
|
1126 |
+
assert A.dcm(N) == Matrix([[sqrt(2) / 2, sqrt(2) / 2, 0],
|
1127 |
+
[-sqrt(2) / 2, sqrt(2) / 2, 0], [0, 0, 1]])
|
1128 |
+
assert A.ang_vel_in(N) == Vector(0)
|
1129 |
+
|
1130 |
+
|
1131 |
+
def test_deprecated_joint_pos():
|
1132 |
+
N, A, P, C = _generate_body()
|
1133 |
+
with warns_deprecated_sympy():
|
1134 |
+
pin = PinJoint('J', P, C, parent_joint_pos=N.x + N.y,
|
1135 |
+
child_joint_pos=C.y - C.z)
|
1136 |
+
assert pin.parent_point.pos_from(P.masscenter) == N.x + N.y
|
1137 |
+
assert pin.child_point.pos_from(C.masscenter) == C.y - C.z
|
1138 |
+
|
1139 |
+
N, A, P, C = _generate_body()
|
1140 |
+
with warns_deprecated_sympy():
|
1141 |
+
slider = PrismaticJoint('J', P, C, parent_joint_pos=N.z + N.y,
|
1142 |
+
child_joint_pos=C.y - C.x)
|
1143 |
+
assert slider.parent_point.pos_from(P.masscenter) == N.z + N.y
|
1144 |
+
assert slider.child_point.pos_from(C.masscenter) == C.y - C.x
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_jointsmethod.py
ADDED
@@ -0,0 +1,212 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.core.function import expand
|
2 |
+
from sympy.core.symbol import symbols
|
3 |
+
from sympy.functions.elementary.trigonometric import (cos, sin)
|
4 |
+
from sympy.matrices.dense import Matrix
|
5 |
+
from sympy.simplify.trigsimp import trigsimp
|
6 |
+
from sympy.physics.mechanics import (PinJoint, JointsMethod, Body, KanesMethod,
|
7 |
+
PrismaticJoint, LagrangesMethod, inertia)
|
8 |
+
from sympy.physics.vector import dynamicsymbols, ReferenceFrame
|
9 |
+
from sympy.testing.pytest import raises
|
10 |
+
from sympy.core.backend import zeros
|
11 |
+
from sympy.utilities.lambdify import lambdify
|
12 |
+
from sympy.solvers.solvers import solve
|
13 |
+
|
14 |
+
|
15 |
+
t = dynamicsymbols._t # type: ignore
|
16 |
+
|
17 |
+
|
18 |
+
def test_jointsmethod():
|
19 |
+
P = Body('P')
|
20 |
+
C = Body('C')
|
21 |
+
Pin = PinJoint('P1', P, C)
|
22 |
+
C_ixx, g = symbols('C_ixx g')
|
23 |
+
q, u = dynamicsymbols('q_P1, u_P1')
|
24 |
+
P.apply_force(g*P.y)
|
25 |
+
method = JointsMethod(P, Pin)
|
26 |
+
assert method.frame == P.frame
|
27 |
+
assert method.bodies == [C, P]
|
28 |
+
assert method.loads == [(P.masscenter, g*P.frame.y)]
|
29 |
+
assert method.q == Matrix([q])
|
30 |
+
assert method.u == Matrix([u])
|
31 |
+
assert method.kdes == Matrix([u - q.diff()])
|
32 |
+
soln = method.form_eoms()
|
33 |
+
assert soln == Matrix([[-C_ixx*u.diff()]])
|
34 |
+
assert method.forcing_full == Matrix([[u], [0]])
|
35 |
+
assert method.mass_matrix_full == Matrix([[1, 0], [0, C_ixx]])
|
36 |
+
assert isinstance(method.method, KanesMethod)
|
37 |
+
|
38 |
+
def test_jointmethod_duplicate_coordinates_speeds():
|
39 |
+
P = Body('P')
|
40 |
+
C = Body('C')
|
41 |
+
T = Body('T')
|
42 |
+
q, u = dynamicsymbols('q u')
|
43 |
+
P1 = PinJoint('P1', P, C, q)
|
44 |
+
P2 = PrismaticJoint('P2', C, T, q)
|
45 |
+
raises(ValueError, lambda: JointsMethod(P, P1, P2))
|
46 |
+
|
47 |
+
P1 = PinJoint('P1', P, C, speeds=u)
|
48 |
+
P2 = PrismaticJoint('P2', C, T, speeds=u)
|
49 |
+
raises(ValueError, lambda: JointsMethod(P, P1, P2))
|
50 |
+
|
51 |
+
P1 = PinJoint('P1', P, C, q, u)
|
52 |
+
P2 = PrismaticJoint('P2', C, T, q, u)
|
53 |
+
raises(ValueError, lambda: JointsMethod(P, P1, P2))
|
54 |
+
|
55 |
+
def test_complete_simple_double_pendulum():
|
56 |
+
q1, q2 = dynamicsymbols('q1 q2')
|
57 |
+
u1, u2 = dynamicsymbols('u1 u2')
|
58 |
+
m, l, g = symbols('m l g')
|
59 |
+
C = Body('C') # ceiling
|
60 |
+
PartP = Body('P', mass=m)
|
61 |
+
PartR = Body('R', mass=m)
|
62 |
+
J1 = PinJoint('J1', C, PartP, speeds=u1, coordinates=q1,
|
63 |
+
child_point=-l*PartP.x, joint_axis=C.z)
|
64 |
+
J2 = PinJoint('J2', PartP, PartR, speeds=u2, coordinates=q2,
|
65 |
+
child_point=-l*PartR.x, joint_axis=PartP.z)
|
66 |
+
|
67 |
+
PartP.apply_force(m*g*C.x)
|
68 |
+
PartR.apply_force(m*g*C.x)
|
69 |
+
|
70 |
+
method = JointsMethod(C, J1, J2)
|
71 |
+
method.form_eoms()
|
72 |
+
|
73 |
+
assert expand(method.mass_matrix_full) == Matrix([[1, 0, 0, 0],
|
74 |
+
[0, 1, 0, 0],
|
75 |
+
[0, 0, 2*l**2*m*cos(q2) + 3*l**2*m, l**2*m*cos(q2) + l**2*m],
|
76 |
+
[0, 0, l**2*m*cos(q2) + l**2*m, l**2*m]])
|
77 |
+
assert trigsimp(method.forcing_full) == trigsimp(Matrix([[u1], [u2], [-g*l*m*(sin(q1 + q2) + sin(q1)) -
|
78 |
+
g*l*m*sin(q1) + l**2*m*(2*u1 + u2)*u2*sin(q2)],
|
79 |
+
[-g*l*m*sin(q1 + q2) - l**2*m*u1**2*sin(q2)]]))
|
80 |
+
|
81 |
+
def test_two_dof_joints():
|
82 |
+
q1, q2, u1, u2 = dynamicsymbols('q1 q2 u1 u2')
|
83 |
+
m, c1, c2, k1, k2 = symbols('m c1 c2 k1 k2')
|
84 |
+
W = Body('W')
|
85 |
+
B1 = Body('B1', mass=m)
|
86 |
+
B2 = Body('B2', mass=m)
|
87 |
+
J1 = PrismaticJoint('J1', W, B1, coordinates=q1, speeds=u1)
|
88 |
+
J2 = PrismaticJoint('J2', B1, B2, coordinates=q2, speeds=u2)
|
89 |
+
W.apply_force(k1*q1*W.x, reaction_body=B1)
|
90 |
+
W.apply_force(c1*u1*W.x, reaction_body=B1)
|
91 |
+
B1.apply_force(k2*q2*W.x, reaction_body=B2)
|
92 |
+
B1.apply_force(c2*u2*W.x, reaction_body=B2)
|
93 |
+
method = JointsMethod(W, J1, J2)
|
94 |
+
method.form_eoms()
|
95 |
+
MM = method.mass_matrix
|
96 |
+
forcing = method.forcing
|
97 |
+
rhs = MM.LUsolve(forcing)
|
98 |
+
assert expand(rhs[0]) == expand((-k1 * q1 - c1 * u1 + k2 * q2 + c2 * u2)/m)
|
99 |
+
assert expand(rhs[1]) == expand((k1 * q1 + c1 * u1 - 2 * k2 * q2 - 2 *
|
100 |
+
c2 * u2) / m)
|
101 |
+
|
102 |
+
def test_simple_pedulum():
|
103 |
+
l, m, g = symbols('l m g')
|
104 |
+
C = Body('C')
|
105 |
+
b = Body('b', mass=m)
|
106 |
+
q = dynamicsymbols('q')
|
107 |
+
P = PinJoint('P', C, b, speeds=q.diff(t), coordinates=q,
|
108 |
+
child_point=-l * b.x, joint_axis=C.z)
|
109 |
+
b.potential_energy = - m * g * l * cos(q)
|
110 |
+
method = JointsMethod(C, P)
|
111 |
+
method.form_eoms(LagrangesMethod)
|
112 |
+
rhs = method.rhs()
|
113 |
+
assert rhs[1] == -g*sin(q)/l
|
114 |
+
|
115 |
+
def test_chaos_pendulum():
|
116 |
+
#https://www.pydy.org/examples/chaos_pendulum.html
|
117 |
+
mA, mB, lA, lB, IAxx, IBxx, IByy, IBzz, g = symbols('mA, mB, lA, lB, IAxx, IBxx, IByy, IBzz, g')
|
118 |
+
theta, phi, omega, alpha = dynamicsymbols('theta phi omega alpha')
|
119 |
+
|
120 |
+
A = ReferenceFrame('A')
|
121 |
+
B = ReferenceFrame('B')
|
122 |
+
|
123 |
+
rod = Body('rod', mass=mA, frame=A, central_inertia=inertia(A, IAxx, IAxx, 0))
|
124 |
+
plate = Body('plate', mass=mB, frame=B, central_inertia=inertia(B, IBxx, IByy, IBzz))
|
125 |
+
C = Body('C')
|
126 |
+
J1 = PinJoint('J1', C, rod, coordinates=theta, speeds=omega,
|
127 |
+
child_point=-lA * rod.z, joint_axis=C.y)
|
128 |
+
J2 = PinJoint('J2', rod, plate, coordinates=phi, speeds=alpha,
|
129 |
+
parent_point=(lB - lA) * rod.z, joint_axis=rod.z)
|
130 |
+
|
131 |
+
rod.apply_force(mA*g*C.z)
|
132 |
+
plate.apply_force(mB*g*C.z)
|
133 |
+
|
134 |
+
method = JointsMethod(C, J1, J2)
|
135 |
+
method.form_eoms()
|
136 |
+
|
137 |
+
MM = method.mass_matrix
|
138 |
+
forcing = method.forcing
|
139 |
+
rhs = MM.LUsolve(forcing)
|
140 |
+
xd = (-2 * IBxx * alpha * omega * sin(phi) * cos(phi) + 2 * IByy * alpha * omega * sin(phi) *
|
141 |
+
cos(phi) - g * lA * mA * sin(theta) - g * lB * mB * sin(theta)) / (IAxx + IBxx *
|
142 |
+
sin(phi)**2 + IByy * cos(phi)**2 + lA**2 * mA + lB**2 * mB)
|
143 |
+
assert (rhs[0] - xd).simplify() == 0
|
144 |
+
xd = (IBxx - IByy) * omega**2 * sin(phi) * cos(phi) / IBzz
|
145 |
+
assert (rhs[1] - xd).simplify() == 0
|
146 |
+
|
147 |
+
def test_four_bar_linkage_with_manual_constraints():
|
148 |
+
q1, q2, q3, u1, u2, u3 = dynamicsymbols('q1:4, u1:4')
|
149 |
+
l1, l2, l3, l4, rho = symbols('l1:5, rho')
|
150 |
+
|
151 |
+
N = ReferenceFrame('N')
|
152 |
+
inertias = [inertia(N, 0, 0, rho * l ** 3 / 12) for l in (l1, l2, l3, l4)]
|
153 |
+
link1 = Body('Link1', frame=N, mass=rho * l1, central_inertia=inertias[0])
|
154 |
+
link2 = Body('Link2', mass=rho * l2, central_inertia=inertias[1])
|
155 |
+
link3 = Body('Link3', mass=rho * l3, central_inertia=inertias[2])
|
156 |
+
link4 = Body('Link4', mass=rho * l4, central_inertia=inertias[3])
|
157 |
+
|
158 |
+
joint1 = PinJoint(
|
159 |
+
'J1', link1, link2, coordinates=q1, speeds=u1, joint_axis=link1.z,
|
160 |
+
parent_point=l1 / 2 * link1.x, child_point=-l2 / 2 * link2.x)
|
161 |
+
joint2 = PinJoint(
|
162 |
+
'J2', link2, link3, coordinates=q2, speeds=u2, joint_axis=link2.z,
|
163 |
+
parent_point=l2 / 2 * link2.x, child_point=-l3 / 2 * link3.x)
|
164 |
+
joint3 = PinJoint(
|
165 |
+
'J3', link3, link4, coordinates=q3, speeds=u3, joint_axis=link3.z,
|
166 |
+
parent_point=l3 / 2 * link3.x, child_point=-l4 / 2 * link4.x)
|
167 |
+
|
168 |
+
loop = link4.masscenter.pos_from(link1.masscenter) \
|
169 |
+
+ l1 / 2 * link1.x + l4 / 2 * link4.x
|
170 |
+
|
171 |
+
fh = Matrix([loop.dot(link1.x), loop.dot(link1.y)])
|
172 |
+
|
173 |
+
method = JointsMethod(link1, joint1, joint2, joint3)
|
174 |
+
|
175 |
+
t = dynamicsymbols._t
|
176 |
+
qdots = solve(method.kdes, [q1.diff(t), q2.diff(t), q3.diff(t)])
|
177 |
+
fhd = fh.diff(t).subs(qdots)
|
178 |
+
|
179 |
+
kane = KanesMethod(method.frame, q_ind=[q1], u_ind=[u1],
|
180 |
+
q_dependent=[q2, q3], u_dependent=[u2, u3],
|
181 |
+
kd_eqs=method.kdes, configuration_constraints=fh,
|
182 |
+
velocity_constraints=fhd, forcelist=method.loads,
|
183 |
+
bodies=method.bodies)
|
184 |
+
fr, frs = kane.kanes_equations()
|
185 |
+
assert fr == zeros(1)
|
186 |
+
|
187 |
+
# Numerically check the mass- and forcing-matrix
|
188 |
+
p = Matrix([l1, l2, l3, l4, rho])
|
189 |
+
q = Matrix([q1, q2, q3])
|
190 |
+
u = Matrix([u1, u2, u3])
|
191 |
+
eval_m = lambdify((q, p), kane.mass_matrix)
|
192 |
+
eval_f = lambdify((q, u, p), kane.forcing)
|
193 |
+
eval_fhd = lambdify((q, u, p), fhd)
|
194 |
+
|
195 |
+
p_vals = [0.13, 0.24, 0.21, 0.34, 997]
|
196 |
+
q_vals = [2.1, 0.6655470375077588, 2.527408138024188] # Satisfies fh
|
197 |
+
u_vals = [0.2, -0.17963733938852067, 0.1309060540601612] # Satisfies fhd
|
198 |
+
mass_check = Matrix([[3.452709815256506e+01, 7.003948798374735e+00,
|
199 |
+
-4.939690970641498e+00],
|
200 |
+
[-2.203792703880936e-14, 2.071702479957077e-01,
|
201 |
+
2.842917573033711e-01],
|
202 |
+
[-1.300000000000123e-01, -8.836934896046506e-03,
|
203 |
+
1.864891330060847e-01]])
|
204 |
+
forcing_check = Matrix([[-0.031211821321648],
|
205 |
+
[-0.00066022608181],
|
206 |
+
[0.001813559741243]])
|
207 |
+
eps = 1e-10
|
208 |
+
assert all(abs(x) < eps for x in eval_fhd(q_vals, u_vals, p_vals))
|
209 |
+
assert all(abs(x) < eps for x in
|
210 |
+
(Matrix(eval_m(q_vals, p_vals)) - mass_check))
|
211 |
+
assert all(abs(x) < eps for x in
|
212 |
+
(Matrix(eval_f(q_vals, u_vals, p_vals)) - forcing_check))
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_kane4.py
ADDED
@@ -0,0 +1,115 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.core.backend import (cos, sin, Matrix, symbols)
|
2 |
+
from sympy.physics.mechanics import (dynamicsymbols, ReferenceFrame, Point,
|
3 |
+
KanesMethod, Particle)
|
4 |
+
|
5 |
+
def test_replace_qdots_in_force():
|
6 |
+
# Test PR 16700 "Replaces qdots with us in force-list in kanes.py"
|
7 |
+
# The new functionality allows one to specify forces in qdots which will
|
8 |
+
# automatically be replaced with u:s which are defined by the kde supplied
|
9 |
+
# to KanesMethod. The test case is the double pendulum with interacting
|
10 |
+
# forces in the example of chapter 4.7 "CONTRIBUTING INTERACTION FORCES"
|
11 |
+
# in Ref. [1]. Reference list at end test function.
|
12 |
+
|
13 |
+
q1, q2 = dynamicsymbols('q1, q2')
|
14 |
+
qd1, qd2 = dynamicsymbols('q1, q2', level=1)
|
15 |
+
u1, u2 = dynamicsymbols('u1, u2')
|
16 |
+
|
17 |
+
l, m = symbols('l, m')
|
18 |
+
|
19 |
+
N = ReferenceFrame('N') # Inertial frame
|
20 |
+
A = N.orientnew('A', 'Axis', (q1, N.z)) # Rod A frame
|
21 |
+
B = A.orientnew('B', 'Axis', (q2, N.z)) # Rod B frame
|
22 |
+
|
23 |
+
O = Point('O') # Origo
|
24 |
+
O.set_vel(N, 0)
|
25 |
+
|
26 |
+
P = O.locatenew('P', ( l * A.x )) # Point @ end of rod A
|
27 |
+
P.v2pt_theory(O, N, A)
|
28 |
+
|
29 |
+
Q = P.locatenew('Q', ( l * B.x )) # Point @ end of rod B
|
30 |
+
Q.v2pt_theory(P, N, B)
|
31 |
+
|
32 |
+
Ap = Particle('Ap', P, m)
|
33 |
+
Bp = Particle('Bp', Q, m)
|
34 |
+
|
35 |
+
# The forces are specified below. sigma is the torsional spring stiffness
|
36 |
+
# and delta is the viscous damping coefficient acting between the two
|
37 |
+
# bodies. Here, we specify the viscous damper as function of qdots prior
|
38 |
+
# forming the kde. In more complex systems it not might be obvious which
|
39 |
+
# kde is most efficient, why it is convenient to specify viscous forces in
|
40 |
+
# qdots independently of the kde.
|
41 |
+
sig, delta = symbols('sigma, delta')
|
42 |
+
Ta = (sig * q2 + delta * qd2) * N.z
|
43 |
+
forces = [(A, Ta), (B, -Ta)]
|
44 |
+
|
45 |
+
# Try different kdes.
|
46 |
+
kde1 = [u1 - qd1, u2 - qd2]
|
47 |
+
kde2 = [u1 - qd1, u2 - (qd1 + qd2)]
|
48 |
+
|
49 |
+
KM1 = KanesMethod(N, [q1, q2], [u1, u2], kd_eqs=kde1)
|
50 |
+
fr1, fstar1 = KM1.kanes_equations([Ap, Bp], forces)
|
51 |
+
|
52 |
+
KM2 = KanesMethod(N, [q1, q2], [u1, u2], kd_eqs=kde2)
|
53 |
+
fr2, fstar2 = KM2.kanes_equations([Ap, Bp], forces)
|
54 |
+
|
55 |
+
# Check EOM for KM2:
|
56 |
+
# Mass and force matrix from p.6 in Ref. [2] with added forces from
|
57 |
+
# example of chapter 4.7 in [1] and without gravity.
|
58 |
+
forcing_matrix_expected = Matrix( [ [ m * l**2 * sin(q2) * u2**2 + sig * q2
|
59 |
+
+ delta * (u2 - u1)],
|
60 |
+
[ m * l**2 * sin(q2) * -u1**2 - sig * q2
|
61 |
+
- delta * (u2 - u1)] ] )
|
62 |
+
mass_matrix_expected = Matrix( [ [ 2 * m * l**2, m * l**2 * cos(q2) ],
|
63 |
+
[ m * l**2 * cos(q2), m * l**2 ] ] )
|
64 |
+
|
65 |
+
assert (KM2.mass_matrix.expand() == mass_matrix_expected.expand())
|
66 |
+
assert (KM2.forcing.expand() == forcing_matrix_expected.expand())
|
67 |
+
|
68 |
+
# Check fr1 with reference fr_expected from [1] with u:s instead of qdots.
|
69 |
+
fr1_expected = Matrix([ 0, -(sig*q2 + delta * u2) ])
|
70 |
+
assert fr1.expand() == fr1_expected.expand()
|
71 |
+
|
72 |
+
# Check fr2
|
73 |
+
fr2_expected = Matrix([sig * q2 + delta * (u2 - u1),
|
74 |
+
- sig * q2 - delta * (u2 - u1)])
|
75 |
+
assert fr2.expand() == fr2_expected.expand()
|
76 |
+
|
77 |
+
# Specifying forces in u:s should stay the same:
|
78 |
+
Ta = (sig * q2 + delta * u2) * N.z
|
79 |
+
forces = [(A, Ta), (B, -Ta)]
|
80 |
+
KM1 = KanesMethod(N, [q1, q2], [u1, u2], kd_eqs=kde1)
|
81 |
+
fr1, fstar1 = KM1.kanes_equations([Ap, Bp], forces)
|
82 |
+
|
83 |
+
assert fr1.expand() == fr1_expected.expand()
|
84 |
+
|
85 |
+
Ta = (sig * q2 + delta * (u2-u1)) * N.z
|
86 |
+
forces = [(A, Ta), (B, -Ta)]
|
87 |
+
KM2 = KanesMethod(N, [q1, q2], [u1, u2], kd_eqs=kde2)
|
88 |
+
fr2, fstar2 = KM2.kanes_equations([Ap, Bp], forces)
|
89 |
+
|
90 |
+
assert fr2.expand() == fr2_expected.expand()
|
91 |
+
|
92 |
+
# Test if we have a qubic qdot force:
|
93 |
+
Ta = (sig * q2 + delta * qd2**3) * N.z
|
94 |
+
forces = [(A, Ta), (B, -Ta)]
|
95 |
+
|
96 |
+
KM1 = KanesMethod(N, [q1, q2], [u1, u2], kd_eqs=kde1)
|
97 |
+
fr1, fstar1 = KM1.kanes_equations([Ap, Bp], forces)
|
98 |
+
|
99 |
+
fr1_cubic_expected = Matrix([ 0, -(sig*q2 + delta * u2**3) ])
|
100 |
+
|
101 |
+
assert fr1.expand() == fr1_cubic_expected.expand()
|
102 |
+
|
103 |
+
KM2 = KanesMethod(N, [q1, q2], [u1, u2], kd_eqs=kde2)
|
104 |
+
fr2, fstar2 = KM2.kanes_equations([Ap, Bp], forces)
|
105 |
+
|
106 |
+
fr2_cubic_expected = Matrix([sig * q2 + delta * (u2 - u1)**3,
|
107 |
+
- sig * q2 - delta * (u2 - u1)**3])
|
108 |
+
|
109 |
+
assert fr2.expand() == fr2_cubic_expected.expand()
|
110 |
+
|
111 |
+
# References:
|
112 |
+
# [1] T.R. Kane, D. a Levinson, Dynamics Theory and Applications, 2005.
|
113 |
+
# [2] Arun K Banerjee, Flexible Multibody Dynamics:Efficient Formulations
|
114 |
+
# and Applications, John Wiley and Sons, Ltd, 2016.
|
115 |
+
# doi:http://dx.doi.org/10.1002/9781119015635.
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_lagrange2.py
ADDED
@@ -0,0 +1,46 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.core.backend import symbols
|
2 |
+
from sympy.physics.mechanics import dynamicsymbols
|
3 |
+
from sympy.physics.mechanics import ReferenceFrame, Point, Particle
|
4 |
+
from sympy.physics.mechanics import LagrangesMethod, Lagrangian
|
5 |
+
|
6 |
+
### This test asserts that a system with more than one external forces
|
7 |
+
### is acurately formed with Lagrange method (see issue #8626)
|
8 |
+
|
9 |
+
def test_lagrange_2forces():
|
10 |
+
### Equations for two damped springs in serie with two forces
|
11 |
+
|
12 |
+
### generalized coordinates
|
13 |
+
q1, q2 = dynamicsymbols('q1, q2')
|
14 |
+
### generalized speeds
|
15 |
+
q1d, q2d = dynamicsymbols('q1, q2', 1)
|
16 |
+
|
17 |
+
### Mass, spring strength, friction coefficient
|
18 |
+
m, k, nu = symbols('m, k, nu')
|
19 |
+
|
20 |
+
N = ReferenceFrame('N')
|
21 |
+
O = Point('O')
|
22 |
+
|
23 |
+
### Two points
|
24 |
+
P1 = O.locatenew('P1', q1 * N.x)
|
25 |
+
P1.set_vel(N, q1d * N.x)
|
26 |
+
P2 = O.locatenew('P1', q2 * N.x)
|
27 |
+
P2.set_vel(N, q2d * N.x)
|
28 |
+
|
29 |
+
pP1 = Particle('pP1', P1, m)
|
30 |
+
pP1.potential_energy = k * q1**2 / 2
|
31 |
+
|
32 |
+
pP2 = Particle('pP2', P2, m)
|
33 |
+
pP2.potential_energy = k * (q1 - q2)**2 / 2
|
34 |
+
|
35 |
+
#### Friction forces
|
36 |
+
forcelist = [(P1, - nu * q1d * N.x),
|
37 |
+
(P2, - nu * q2d * N.x)]
|
38 |
+
lag = Lagrangian(N, pP1, pP2)
|
39 |
+
|
40 |
+
l_method = LagrangesMethod(lag, (q1, q2), forcelist=forcelist, frame=N)
|
41 |
+
l_method.form_lagranges_equations()
|
42 |
+
|
43 |
+
eq1 = l_method.eom[0]
|
44 |
+
assert eq1.diff(q1d) == nu
|
45 |
+
eq2 = l_method.eom[1]
|
46 |
+
assert eq2.diff(q2d) == nu
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_method.py
ADDED
@@ -0,0 +1,5 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.physics.mechanics.method import _Methods
|
2 |
+
from sympy.testing.pytest import raises
|
3 |
+
|
4 |
+
def test_method():
|
5 |
+
raises(TypeError, lambda: _Methods())
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_models.py
ADDED
@@ -0,0 +1,117 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
import sympy.physics.mechanics.models as models
|
2 |
+
from sympy.core.backend import (cos, sin, Matrix, symbols, zeros)
|
3 |
+
from sympy.simplify.simplify import simplify
|
4 |
+
from sympy.physics.mechanics import (dynamicsymbols)
|
5 |
+
|
6 |
+
|
7 |
+
def test_multi_mass_spring_damper_inputs():
|
8 |
+
|
9 |
+
c0, k0, m0 = symbols("c0 k0 m0")
|
10 |
+
g = symbols("g")
|
11 |
+
v0, x0, f0 = dynamicsymbols("v0 x0 f0")
|
12 |
+
|
13 |
+
kane1 = models.multi_mass_spring_damper(1)
|
14 |
+
massmatrix1 = Matrix([[m0]])
|
15 |
+
forcing1 = Matrix([[-c0*v0 - k0*x0]])
|
16 |
+
assert simplify(massmatrix1 - kane1.mass_matrix) == Matrix([0])
|
17 |
+
assert simplify(forcing1 - kane1.forcing) == Matrix([0])
|
18 |
+
|
19 |
+
kane2 = models.multi_mass_spring_damper(1, True)
|
20 |
+
massmatrix2 = Matrix([[m0]])
|
21 |
+
forcing2 = Matrix([[-c0*v0 + g*m0 - k0*x0]])
|
22 |
+
assert simplify(massmatrix2 - kane2.mass_matrix) == Matrix([0])
|
23 |
+
assert simplify(forcing2 - kane2.forcing) == Matrix([0])
|
24 |
+
|
25 |
+
kane3 = models.multi_mass_spring_damper(1, True, True)
|
26 |
+
massmatrix3 = Matrix([[m0]])
|
27 |
+
forcing3 = Matrix([[-c0*v0 + g*m0 - k0*x0 + f0]])
|
28 |
+
assert simplify(massmatrix3 - kane3.mass_matrix) == Matrix([0])
|
29 |
+
assert simplify(forcing3 - kane3.forcing) == Matrix([0])
|
30 |
+
|
31 |
+
kane4 = models.multi_mass_spring_damper(1, False, True)
|
32 |
+
massmatrix4 = Matrix([[m0]])
|
33 |
+
forcing4 = Matrix([[-c0*v0 - k0*x0 + f0]])
|
34 |
+
assert simplify(massmatrix4 - kane4.mass_matrix) == Matrix([0])
|
35 |
+
assert simplify(forcing4 - kane4.forcing) == Matrix([0])
|
36 |
+
|
37 |
+
|
38 |
+
def test_multi_mass_spring_damper_higher_order():
|
39 |
+
c0, k0, m0 = symbols("c0 k0 m0")
|
40 |
+
c1, k1, m1 = symbols("c1 k1 m1")
|
41 |
+
c2, k2, m2 = symbols("c2 k2 m2")
|
42 |
+
v0, x0 = dynamicsymbols("v0 x0")
|
43 |
+
v1, x1 = dynamicsymbols("v1 x1")
|
44 |
+
v2, x2 = dynamicsymbols("v2 x2")
|
45 |
+
|
46 |
+
kane1 = models.multi_mass_spring_damper(3)
|
47 |
+
massmatrix1 = Matrix([[m0 + m1 + m2, m1 + m2, m2],
|
48 |
+
[m1 + m2, m1 + m2, m2],
|
49 |
+
[m2, m2, m2]])
|
50 |
+
forcing1 = Matrix([[-c0*v0 - k0*x0],
|
51 |
+
[-c1*v1 - k1*x1],
|
52 |
+
[-c2*v2 - k2*x2]])
|
53 |
+
assert simplify(massmatrix1 - kane1.mass_matrix) == zeros(3)
|
54 |
+
assert simplify(forcing1 - kane1.forcing) == Matrix([0, 0, 0])
|
55 |
+
|
56 |
+
|
57 |
+
def test_n_link_pendulum_on_cart_inputs():
|
58 |
+
l0, m0 = symbols("l0 m0")
|
59 |
+
m1 = symbols("m1")
|
60 |
+
g = symbols("g")
|
61 |
+
q0, q1, F, T1 = dynamicsymbols("q0 q1 F T1")
|
62 |
+
u0, u1 = dynamicsymbols("u0 u1")
|
63 |
+
|
64 |
+
kane1 = models.n_link_pendulum_on_cart(1)
|
65 |
+
massmatrix1 = Matrix([[m0 + m1, -l0*m1*cos(q1)],
|
66 |
+
[-l0*m1*cos(q1), l0**2*m1]])
|
67 |
+
forcing1 = Matrix([[-l0*m1*u1**2*sin(q1) + F], [g*l0*m1*sin(q1)]])
|
68 |
+
assert simplify(massmatrix1 - kane1.mass_matrix) == zeros(2)
|
69 |
+
assert simplify(forcing1 - kane1.forcing) == Matrix([0, 0])
|
70 |
+
|
71 |
+
kane2 = models.n_link_pendulum_on_cart(1, False)
|
72 |
+
massmatrix2 = Matrix([[m0 + m1, -l0*m1*cos(q1)],
|
73 |
+
[-l0*m1*cos(q1), l0**2*m1]])
|
74 |
+
forcing2 = Matrix([[-l0*m1*u1**2*sin(q1)], [g*l0*m1*sin(q1)]])
|
75 |
+
assert simplify(massmatrix2 - kane2.mass_matrix) == zeros(2)
|
76 |
+
assert simplify(forcing2 - kane2.forcing) == Matrix([0, 0])
|
77 |
+
|
78 |
+
kane3 = models.n_link_pendulum_on_cart(1, False, True)
|
79 |
+
massmatrix3 = Matrix([[m0 + m1, -l0*m1*cos(q1)],
|
80 |
+
[-l0*m1*cos(q1), l0**2*m1]])
|
81 |
+
forcing3 = Matrix([[-l0*m1*u1**2*sin(q1)], [g*l0*m1*sin(q1) + T1]])
|
82 |
+
assert simplify(massmatrix3 - kane3.mass_matrix) == zeros(2)
|
83 |
+
assert simplify(forcing3 - kane3.forcing) == Matrix([0, 0])
|
84 |
+
|
85 |
+
kane4 = models.n_link_pendulum_on_cart(1, True, False)
|
86 |
+
massmatrix4 = Matrix([[m0 + m1, -l0*m1*cos(q1)],
|
87 |
+
[-l0*m1*cos(q1), l0**2*m1]])
|
88 |
+
forcing4 = Matrix([[-l0*m1*u1**2*sin(q1) + F], [g*l0*m1*sin(q1)]])
|
89 |
+
assert simplify(massmatrix4 - kane4.mass_matrix) == zeros(2)
|
90 |
+
assert simplify(forcing4 - kane4.forcing) == Matrix([0, 0])
|
91 |
+
|
92 |
+
|
93 |
+
def test_n_link_pendulum_on_cart_higher_order():
|
94 |
+
l0, m0 = symbols("l0 m0")
|
95 |
+
l1, m1 = symbols("l1 m1")
|
96 |
+
m2 = symbols("m2")
|
97 |
+
g = symbols("g")
|
98 |
+
q0, q1, q2 = dynamicsymbols("q0 q1 q2")
|
99 |
+
u0, u1, u2 = dynamicsymbols("u0 u1 u2")
|
100 |
+
F, T1 = dynamicsymbols("F T1")
|
101 |
+
|
102 |
+
kane1 = models.n_link_pendulum_on_cart(2)
|
103 |
+
massmatrix1 = Matrix([[m0 + m1 + m2, -l0*m1*cos(q1) - l0*m2*cos(q1),
|
104 |
+
-l1*m2*cos(q2)],
|
105 |
+
[-l0*m1*cos(q1) - l0*m2*cos(q1), l0**2*m1 + l0**2*m2,
|
106 |
+
l0*l1*m2*(sin(q1)*sin(q2) + cos(q1)*cos(q2))],
|
107 |
+
[-l1*m2*cos(q2),
|
108 |
+
l0*l1*m2*(sin(q1)*sin(q2) + cos(q1)*cos(q2)),
|
109 |
+
l1**2*m2]])
|
110 |
+
forcing1 = Matrix([[-l0*m1*u1**2*sin(q1) - l0*m2*u1**2*sin(q1) -
|
111 |
+
l1*m2*u2**2*sin(q2) + F],
|
112 |
+
[g*l0*m1*sin(q1) + g*l0*m2*sin(q1) -
|
113 |
+
l0*l1*m2*(sin(q1)*cos(q2) - sin(q2)*cos(q1))*u2**2],
|
114 |
+
[g*l1*m2*sin(q2) - l0*l1*m2*(-sin(q1)*cos(q2) +
|
115 |
+
sin(q2)*cos(q1))*u1**2]])
|
116 |
+
assert simplify(massmatrix1 - kane1.mass_matrix) == zeros(3)
|
117 |
+
assert simplify(forcing1 - kane1.forcing) == Matrix([0, 0, 0])
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/mechanics/tests/test_system.py
ADDED
@@ -0,0 +1,245 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.core.backend import symbols, Matrix, atan, zeros
|
2 |
+
from sympy.simplify.simplify import simplify
|
3 |
+
from sympy.physics.mechanics import (dynamicsymbols, Particle, Point,
|
4 |
+
ReferenceFrame, SymbolicSystem)
|
5 |
+
from sympy.testing.pytest import raises
|
6 |
+
|
7 |
+
# This class is going to be tested using a simple pendulum set up in x and y
|
8 |
+
# coordinates
|
9 |
+
x, y, u, v, lam = dynamicsymbols('x y u v lambda')
|
10 |
+
m, l, g = symbols('m l g')
|
11 |
+
|
12 |
+
# Set up the different forms the equations can take
|
13 |
+
# [1] Explicit form where the kinematics and dynamics are combined
|
14 |
+
# x' = F(x, t, r, p)
|
15 |
+
#
|
16 |
+
# [2] Implicit form where the kinematics and dynamics are combined
|
17 |
+
# M(x, p) x' = F(x, t, r, p)
|
18 |
+
#
|
19 |
+
# [3] Implicit form where the kinematics and dynamics are separate
|
20 |
+
# M(q, p) u' = F(q, u, t, r, p)
|
21 |
+
# q' = G(q, u, t, r, p)
|
22 |
+
dyn_implicit_mat = Matrix([[1, 0, -x/m],
|
23 |
+
[0, 1, -y/m],
|
24 |
+
[0, 0, l**2/m]])
|
25 |
+
|
26 |
+
dyn_implicit_rhs = Matrix([0, 0, u**2 + v**2 - g*y])
|
27 |
+
|
28 |
+
comb_implicit_mat = Matrix([[1, 0, 0, 0, 0],
|
29 |
+
[0, 1, 0, 0, 0],
|
30 |
+
[0, 0, 1, 0, -x/m],
|
31 |
+
[0, 0, 0, 1, -y/m],
|
32 |
+
[0, 0, 0, 0, l**2/m]])
|
33 |
+
|
34 |
+
comb_implicit_rhs = Matrix([u, v, 0, 0, u**2 + v**2 - g*y])
|
35 |
+
|
36 |
+
kin_explicit_rhs = Matrix([u, v])
|
37 |
+
|
38 |
+
comb_explicit_rhs = comb_implicit_mat.LUsolve(comb_implicit_rhs)
|
39 |
+
|
40 |
+
# Set up a body and load to pass into the system
|
41 |
+
theta = atan(x/y)
|
42 |
+
N = ReferenceFrame('N')
|
43 |
+
A = N.orientnew('A', 'Axis', [theta, N.z])
|
44 |
+
O = Point('O')
|
45 |
+
P = O.locatenew('P', l * A.x)
|
46 |
+
|
47 |
+
Pa = Particle('Pa', P, m)
|
48 |
+
|
49 |
+
bodies = [Pa]
|
50 |
+
loads = [(P, g * m * N.x)]
|
51 |
+
|
52 |
+
# Set up some output equations to be given to SymbolicSystem
|
53 |
+
# Change to make these fit the pendulum
|
54 |
+
PE = symbols("PE")
|
55 |
+
out_eqns = {PE: m*g*(l+y)}
|
56 |
+
|
57 |
+
# Set up remaining arguments that can be passed to SymbolicSystem
|
58 |
+
alg_con = [2]
|
59 |
+
alg_con_full = [4]
|
60 |
+
coordinates = (x, y, lam)
|
61 |
+
speeds = (u, v)
|
62 |
+
states = (x, y, u, v, lam)
|
63 |
+
coord_idxs = (0, 1)
|
64 |
+
speed_idxs = (2, 3)
|
65 |
+
|
66 |
+
|
67 |
+
def test_form_1():
|
68 |
+
symsystem1 = SymbolicSystem(states, comb_explicit_rhs,
|
69 |
+
alg_con=alg_con_full, output_eqns=out_eqns,
|
70 |
+
coord_idxs=coord_idxs, speed_idxs=speed_idxs,
|
71 |
+
bodies=bodies, loads=loads)
|
72 |
+
|
73 |
+
assert symsystem1.coordinates == Matrix([x, y])
|
74 |
+
assert symsystem1.speeds == Matrix([u, v])
|
75 |
+
assert symsystem1.states == Matrix([x, y, u, v, lam])
|
76 |
+
|
77 |
+
assert symsystem1.alg_con == [4]
|
78 |
+
|
79 |
+
inter = comb_explicit_rhs
|
80 |
+
assert simplify(symsystem1.comb_explicit_rhs - inter) == zeros(5, 1)
|
81 |
+
|
82 |
+
assert set(symsystem1.dynamic_symbols()) == {y, v, lam, u, x}
|
83 |
+
assert type(symsystem1.dynamic_symbols()) == tuple
|
84 |
+
assert set(symsystem1.constant_symbols()) == {l, g, m}
|
85 |
+
assert type(symsystem1.constant_symbols()) == tuple
|
86 |
+
|
87 |
+
assert symsystem1.output_eqns == out_eqns
|
88 |
+
|
89 |
+
assert symsystem1.bodies == (Pa,)
|
90 |
+
assert symsystem1.loads == ((P, g * m * N.x),)
|
91 |
+
|
92 |
+
|
93 |
+
def test_form_2():
|
94 |
+
symsystem2 = SymbolicSystem(coordinates, comb_implicit_rhs, speeds=speeds,
|
95 |
+
mass_matrix=comb_implicit_mat,
|
96 |
+
alg_con=alg_con_full, output_eqns=out_eqns,
|
97 |
+
bodies=bodies, loads=loads)
|
98 |
+
|
99 |
+
assert symsystem2.coordinates == Matrix([x, y, lam])
|
100 |
+
assert symsystem2.speeds == Matrix([u, v])
|
101 |
+
assert symsystem2.states == Matrix([x, y, lam, u, v])
|
102 |
+
|
103 |
+
assert symsystem2.alg_con == [4]
|
104 |
+
|
105 |
+
inter = comb_implicit_rhs
|
106 |
+
assert simplify(symsystem2.comb_implicit_rhs - inter) == zeros(5, 1)
|
107 |
+
assert simplify(symsystem2.comb_implicit_mat-comb_implicit_mat) == zeros(5)
|
108 |
+
|
109 |
+
assert set(symsystem2.dynamic_symbols()) == {y, v, lam, u, x}
|
110 |
+
assert type(symsystem2.dynamic_symbols()) == tuple
|
111 |
+
assert set(symsystem2.constant_symbols()) == {l, g, m}
|
112 |
+
assert type(symsystem2.constant_symbols()) == tuple
|
113 |
+
|
114 |
+
inter = comb_explicit_rhs
|
115 |
+
symsystem2.compute_explicit_form()
|
116 |
+
assert simplify(symsystem2.comb_explicit_rhs - inter) == zeros(5, 1)
|
117 |
+
|
118 |
+
|
119 |
+
assert symsystem2.output_eqns == out_eqns
|
120 |
+
|
121 |
+
assert symsystem2.bodies == (Pa,)
|
122 |
+
assert symsystem2.loads == ((P, g * m * N.x),)
|
123 |
+
|
124 |
+
|
125 |
+
def test_form_3():
|
126 |
+
symsystem3 = SymbolicSystem(states, dyn_implicit_rhs,
|
127 |
+
mass_matrix=dyn_implicit_mat,
|
128 |
+
coordinate_derivatives=kin_explicit_rhs,
|
129 |
+
alg_con=alg_con, coord_idxs=coord_idxs,
|
130 |
+
speed_idxs=speed_idxs, bodies=bodies,
|
131 |
+
loads=loads)
|
132 |
+
|
133 |
+
assert symsystem3.coordinates == Matrix([x, y])
|
134 |
+
assert symsystem3.speeds == Matrix([u, v])
|
135 |
+
assert symsystem3.states == Matrix([x, y, u, v, lam])
|
136 |
+
|
137 |
+
assert symsystem3.alg_con == [4]
|
138 |
+
|
139 |
+
inter1 = kin_explicit_rhs
|
140 |
+
inter2 = dyn_implicit_rhs
|
141 |
+
assert simplify(symsystem3.kin_explicit_rhs - inter1) == zeros(2, 1)
|
142 |
+
assert simplify(symsystem3.dyn_implicit_mat - dyn_implicit_mat) == zeros(3)
|
143 |
+
assert simplify(symsystem3.dyn_implicit_rhs - inter2) == zeros(3, 1)
|
144 |
+
|
145 |
+
inter = comb_implicit_rhs
|
146 |
+
assert simplify(symsystem3.comb_implicit_rhs - inter) == zeros(5, 1)
|
147 |
+
assert simplify(symsystem3.comb_implicit_mat-comb_implicit_mat) == zeros(5)
|
148 |
+
|
149 |
+
inter = comb_explicit_rhs
|
150 |
+
symsystem3.compute_explicit_form()
|
151 |
+
assert simplify(symsystem3.comb_explicit_rhs - inter) == zeros(5, 1)
|
152 |
+
|
153 |
+
assert set(symsystem3.dynamic_symbols()) == {y, v, lam, u, x}
|
154 |
+
assert type(symsystem3.dynamic_symbols()) == tuple
|
155 |
+
assert set(symsystem3.constant_symbols()) == {l, g, m}
|
156 |
+
assert type(symsystem3.constant_symbols()) == tuple
|
157 |
+
|
158 |
+
assert symsystem3.output_eqns == {}
|
159 |
+
|
160 |
+
assert symsystem3.bodies == (Pa,)
|
161 |
+
assert symsystem3.loads == ((P, g * m * N.x),)
|
162 |
+
|
163 |
+
|
164 |
+
def test_property_attributes():
|
165 |
+
symsystem = SymbolicSystem(states, comb_explicit_rhs,
|
166 |
+
alg_con=alg_con_full, output_eqns=out_eqns,
|
167 |
+
coord_idxs=coord_idxs, speed_idxs=speed_idxs,
|
168 |
+
bodies=bodies, loads=loads)
|
169 |
+
|
170 |
+
with raises(AttributeError):
|
171 |
+
symsystem.bodies = 42
|
172 |
+
with raises(AttributeError):
|
173 |
+
symsystem.coordinates = 42
|
174 |
+
with raises(AttributeError):
|
175 |
+
symsystem.dyn_implicit_rhs = 42
|
176 |
+
with raises(AttributeError):
|
177 |
+
symsystem.comb_implicit_rhs = 42
|
178 |
+
with raises(AttributeError):
|
179 |
+
symsystem.loads = 42
|
180 |
+
with raises(AttributeError):
|
181 |
+
symsystem.dyn_implicit_mat = 42
|
182 |
+
with raises(AttributeError):
|
183 |
+
symsystem.comb_implicit_mat = 42
|
184 |
+
with raises(AttributeError):
|
185 |
+
symsystem.kin_explicit_rhs = 42
|
186 |
+
with raises(AttributeError):
|
187 |
+
symsystem.comb_explicit_rhs = 42
|
188 |
+
with raises(AttributeError):
|
189 |
+
symsystem.speeds = 42
|
190 |
+
with raises(AttributeError):
|
191 |
+
symsystem.states = 42
|
192 |
+
with raises(AttributeError):
|
193 |
+
symsystem.alg_con = 42
|
194 |
+
|
195 |
+
|
196 |
+
def test_not_specified_errors():
|
197 |
+
"""This test will cover errors that arise from trying to access attributes
|
198 |
+
that were not specified upon object creation or were specified on creation
|
199 |
+
and the user tries to recalculate them."""
|
200 |
+
# Trying to access form 2 when form 1 given
|
201 |
+
# Trying to access form 3 when form 2 given
|
202 |
+
|
203 |
+
symsystem1 = SymbolicSystem(states, comb_explicit_rhs)
|
204 |
+
|
205 |
+
with raises(AttributeError):
|
206 |
+
symsystem1.comb_implicit_mat
|
207 |
+
with raises(AttributeError):
|
208 |
+
symsystem1.comb_implicit_rhs
|
209 |
+
with raises(AttributeError):
|
210 |
+
symsystem1.dyn_implicit_mat
|
211 |
+
with raises(AttributeError):
|
212 |
+
symsystem1.dyn_implicit_rhs
|
213 |
+
with raises(AttributeError):
|
214 |
+
symsystem1.kin_explicit_rhs
|
215 |
+
with raises(AttributeError):
|
216 |
+
symsystem1.compute_explicit_form()
|
217 |
+
|
218 |
+
symsystem2 = SymbolicSystem(coordinates, comb_implicit_rhs, speeds=speeds,
|
219 |
+
mass_matrix=comb_implicit_mat)
|
220 |
+
|
221 |
+
with raises(AttributeError):
|
222 |
+
symsystem2.dyn_implicit_mat
|
223 |
+
with raises(AttributeError):
|
224 |
+
symsystem2.dyn_implicit_rhs
|
225 |
+
with raises(AttributeError):
|
226 |
+
symsystem2.kin_explicit_rhs
|
227 |
+
|
228 |
+
# Attribute error when trying to access coordinates and speeds when only the
|
229 |
+
# states were given.
|
230 |
+
with raises(AttributeError):
|
231 |
+
symsystem1.coordinates
|
232 |
+
with raises(AttributeError):
|
233 |
+
symsystem1.speeds
|
234 |
+
|
235 |
+
# Attribute error when trying to access bodies and loads when they are not
|
236 |
+
# given
|
237 |
+
with raises(AttributeError):
|
238 |
+
symsystem1.bodies
|
239 |
+
with raises(AttributeError):
|
240 |
+
symsystem1.loads
|
241 |
+
|
242 |
+
# Attribute error when trying to access comb_explicit_rhs before it was
|
243 |
+
# calculated
|
244 |
+
with raises(AttributeError):
|
245 |
+
symsystem2.comb_explicit_rhs
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/sho.py
ADDED
@@ -0,0 +1,95 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.core import S, pi, Rational
|
2 |
+
from sympy.functions import assoc_laguerre, sqrt, exp, factorial, factorial2
|
3 |
+
|
4 |
+
|
5 |
+
def R_nl(n, l, nu, r):
|
6 |
+
"""
|
7 |
+
Returns the radial wavefunction R_{nl} for a 3d isotropic harmonic
|
8 |
+
oscillator.
|
9 |
+
|
10 |
+
Parameters
|
11 |
+
==========
|
12 |
+
|
13 |
+
n :
|
14 |
+
The "nodal" quantum number. Corresponds to the number of nodes in
|
15 |
+
the wavefunction. ``n >= 0``
|
16 |
+
l :
|
17 |
+
The quantum number for orbital angular momentum.
|
18 |
+
nu :
|
19 |
+
mass-scaled frequency: nu = m*omega/(2*hbar) where `m` is the mass
|
20 |
+
and `omega` the frequency of the oscillator.
|
21 |
+
(in atomic units ``nu == omega/2``)
|
22 |
+
r :
|
23 |
+
Radial coordinate.
|
24 |
+
|
25 |
+
Examples
|
26 |
+
========
|
27 |
+
|
28 |
+
>>> from sympy.physics.sho import R_nl
|
29 |
+
>>> from sympy.abc import r, nu, l
|
30 |
+
>>> R_nl(0, 0, 1, r)
|
31 |
+
2*2**(3/4)*exp(-r**2)/pi**(1/4)
|
32 |
+
>>> R_nl(1, 0, 1, r)
|
33 |
+
4*2**(1/4)*sqrt(3)*(3/2 - 2*r**2)*exp(-r**2)/(3*pi**(1/4))
|
34 |
+
|
35 |
+
l, nu and r may be symbolic:
|
36 |
+
|
37 |
+
>>> R_nl(0, 0, nu, r)
|
38 |
+
2*2**(3/4)*sqrt(nu**(3/2))*exp(-nu*r**2)/pi**(1/4)
|
39 |
+
>>> R_nl(0, l, 1, r)
|
40 |
+
r**l*sqrt(2**(l + 3/2)*2**(l + 2)/factorial2(2*l + 1))*exp(-r**2)/pi**(1/4)
|
41 |
+
|
42 |
+
The normalization of the radial wavefunction is:
|
43 |
+
|
44 |
+
>>> from sympy import Integral, oo
|
45 |
+
>>> Integral(R_nl(0, 0, 1, r)**2*r**2, (r, 0, oo)).n()
|
46 |
+
1.00000000000000
|
47 |
+
>>> Integral(R_nl(1, 0, 1, r)**2*r**2, (r, 0, oo)).n()
|
48 |
+
1.00000000000000
|
49 |
+
>>> Integral(R_nl(1, 1, 1, r)**2*r**2, (r, 0, oo)).n()
|
50 |
+
1.00000000000000
|
51 |
+
|
52 |
+
"""
|
53 |
+
n, l, nu, r = map(S, [n, l, nu, r])
|
54 |
+
|
55 |
+
# formula uses n >= 1 (instead of nodal n >= 0)
|
56 |
+
n = n + 1
|
57 |
+
C = sqrt(
|
58 |
+
((2*nu)**(l + Rational(3, 2))*2**(n + l + 1)*factorial(n - 1))/
|
59 |
+
(sqrt(pi)*(factorial2(2*n + 2*l - 1)))
|
60 |
+
)
|
61 |
+
return C*r**(l)*exp(-nu*r**2)*assoc_laguerre(n - 1, l + S.Half, 2*nu*r**2)
|
62 |
+
|
63 |
+
|
64 |
+
def E_nl(n, l, hw):
|
65 |
+
"""
|
66 |
+
Returns the Energy of an isotropic harmonic oscillator.
|
67 |
+
|
68 |
+
Parameters
|
69 |
+
==========
|
70 |
+
|
71 |
+
n :
|
72 |
+
The "nodal" quantum number.
|
73 |
+
l :
|
74 |
+
The orbital angular momentum.
|
75 |
+
hw :
|
76 |
+
The harmonic oscillator parameter.
|
77 |
+
|
78 |
+
Notes
|
79 |
+
=====
|
80 |
+
|
81 |
+
The unit of the returned value matches the unit of hw, since the energy is
|
82 |
+
calculated as:
|
83 |
+
|
84 |
+
E_nl = (2*n + l + 3/2)*hw
|
85 |
+
|
86 |
+
Examples
|
87 |
+
========
|
88 |
+
|
89 |
+
>>> from sympy.physics.sho import E_nl
|
90 |
+
>>> from sympy import symbols
|
91 |
+
>>> x, y, z = symbols('x, y, z')
|
92 |
+
>>> E_nl(x, y, z)
|
93 |
+
z*(2*x + y + 3/2)
|
94 |
+
"""
|
95 |
+
return (2*n + l + Rational(3, 2))*hw
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/__init__.py
ADDED
File without changes
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/__pycache__/__init__.cpython-310.pyc
ADDED
Binary file (192 Bytes). View file
|
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/__pycache__/test_clebsch_gordan.cpython-310.pyc
ADDED
Binary file (7.87 kB). View file
|
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/__pycache__/test_hydrogen.cpython-310.pyc
ADDED
Binary file (5.27 kB). View file
|
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/__pycache__/test_paulialgebra.cpython-310.pyc
ADDED
Binary file (1.63 kB). View file
|
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/__pycache__/test_physics_matrices.cpython-310.pyc
ADDED
Binary file (2.59 kB). View file
|
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/__pycache__/test_pring.cpython-310.pyc
ADDED
Binary file (1.75 kB). View file
|
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/__pycache__/test_qho_1d.cpython-310.pyc
ADDED
Binary file (2.27 kB). View file
|
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/__pycache__/test_secondquant.cpython-310.pyc
ADDED
Binary file (38 kB). View file
|
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/__pycache__/test_sho.cpython-310.pyc
ADDED
Binary file (1.08 kB). View file
|
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/test_clebsch_gordan.py
ADDED
@@ -0,0 +1,191 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.core.numbers import (I, pi, Rational)
|
2 |
+
from sympy.core.singleton import S
|
3 |
+
from sympy.core.symbol import symbols
|
4 |
+
from sympy.functions.elementary.exponential import exp
|
5 |
+
from sympy.functions.elementary.miscellaneous import sqrt
|
6 |
+
from sympy.functions.elementary.trigonometric import (cos, sin)
|
7 |
+
from sympy.functions.special.spherical_harmonics import Ynm
|
8 |
+
from sympy.matrices.dense import Matrix
|
9 |
+
from sympy.physics.wigner import (clebsch_gordan, wigner_9j, wigner_6j, gaunt,
|
10 |
+
real_gaunt, racah, dot_rot_grad_Ynm, wigner_3j, wigner_d_small, wigner_d)
|
11 |
+
from sympy.testing.pytest import raises
|
12 |
+
|
13 |
+
# for test cases, refer : https://en.wikipedia.org/wiki/Table_of_Clebsch%E2%80%93Gordan_coefficients
|
14 |
+
|
15 |
+
def test_clebsch_gordan_docs():
|
16 |
+
assert clebsch_gordan(Rational(3, 2), S.Half, 2, Rational(3, 2), S.Half, 2) == 1
|
17 |
+
assert clebsch_gordan(Rational(3, 2), S.Half, 1, Rational(3, 2), Rational(-1, 2), 1) == sqrt(3)/2
|
18 |
+
assert clebsch_gordan(Rational(3, 2), S.Half, 1, Rational(-1, 2), S.Half, 0) == -sqrt(2)/2
|
19 |
+
|
20 |
+
|
21 |
+
def test_clebsch_gordan():
|
22 |
+
# Argument order: (j_1, j_2, j, m_1, m_2, m)
|
23 |
+
|
24 |
+
h = S.One
|
25 |
+
k = S.Half
|
26 |
+
l = Rational(3, 2)
|
27 |
+
i = Rational(-1, 2)
|
28 |
+
n = Rational(7, 2)
|
29 |
+
p = Rational(5, 2)
|
30 |
+
assert clebsch_gordan(k, k, 1, k, k, 1) == 1
|
31 |
+
assert clebsch_gordan(k, k, 1, k, k, 0) == 0
|
32 |
+
assert clebsch_gordan(k, k, 1, i, i, -1) == 1
|
33 |
+
assert clebsch_gordan(k, k, 1, k, i, 0) == sqrt(2)/2
|
34 |
+
assert clebsch_gordan(k, k, 0, k, i, 0) == sqrt(2)/2
|
35 |
+
assert clebsch_gordan(k, k, 1, i, k, 0) == sqrt(2)/2
|
36 |
+
assert clebsch_gordan(k, k, 0, i, k, 0) == -sqrt(2)/2
|
37 |
+
assert clebsch_gordan(h, k, l, 1, k, l) == 1
|
38 |
+
assert clebsch_gordan(h, k, l, 1, i, k) == 1/sqrt(3)
|
39 |
+
assert clebsch_gordan(h, k, k, 1, i, k) == sqrt(2)/sqrt(3)
|
40 |
+
assert clebsch_gordan(h, k, k, 0, k, k) == -1/sqrt(3)
|
41 |
+
assert clebsch_gordan(h, k, l, 0, k, k) == sqrt(2)/sqrt(3)
|
42 |
+
assert clebsch_gordan(h, h, S(2), 1, 1, S(2)) == 1
|
43 |
+
assert clebsch_gordan(h, h, S(2), 1, 0, 1) == 1/sqrt(2)
|
44 |
+
assert clebsch_gordan(h, h, S(2), 0, 1, 1) == 1/sqrt(2)
|
45 |
+
assert clebsch_gordan(h, h, 1, 1, 0, 1) == 1/sqrt(2)
|
46 |
+
assert clebsch_gordan(h, h, 1, 0, 1, 1) == -1/sqrt(2)
|
47 |
+
assert clebsch_gordan(l, l, S(3), l, l, S(3)) == 1
|
48 |
+
assert clebsch_gordan(l, l, S(2), l, k, S(2)) == 1/sqrt(2)
|
49 |
+
assert clebsch_gordan(l, l, S(3), l, k, S(2)) == 1/sqrt(2)
|
50 |
+
assert clebsch_gordan(S(2), S(2), S(4), S(2), S(2), S(4)) == 1
|
51 |
+
assert clebsch_gordan(S(2), S(2), S(3), S(2), 1, S(3)) == 1/sqrt(2)
|
52 |
+
assert clebsch_gordan(S(2), S(2), S(3), 1, 1, S(2)) == 0
|
53 |
+
assert clebsch_gordan(p, h, n, p, 1, n) == 1
|
54 |
+
assert clebsch_gordan(p, h, p, p, 0, p) == sqrt(5)/sqrt(7)
|
55 |
+
assert clebsch_gordan(p, h, l, k, 1, l) == 1/sqrt(15)
|
56 |
+
|
57 |
+
|
58 |
+
def test_wigner():
|
59 |
+
def tn(a, b):
|
60 |
+
return (a - b).n(64) < S('1e-64')
|
61 |
+
assert tn(wigner_9j(1, 1, 1, 1, 1, 1, 1, 1, 0, prec=64), Rational(1, 18))
|
62 |
+
assert wigner_9j(3, 3, 2, 3, 3, 2, 3, 3, 2) == 3221*sqrt(
|
63 |
+
70)/(246960*sqrt(105)) - 365/(3528*sqrt(70)*sqrt(105))
|
64 |
+
assert wigner_6j(5, 5, 5, 5, 5, 5) == Rational(1, 52)
|
65 |
+
assert tn(wigner_6j(8, 8, 8, 8, 8, 8, prec=64), Rational(-12219, 965770))
|
66 |
+
# regression test for #8747
|
67 |
+
half = S.Half
|
68 |
+
assert wigner_9j(0, 0, 0, 0, half, half, 0, half, half) == half
|
69 |
+
assert (wigner_9j(3, 5, 4,
|
70 |
+
7 * half, 5 * half, 4,
|
71 |
+
9 * half, 9 * half, 0)
|
72 |
+
== -sqrt(Rational(361, 205821000)))
|
73 |
+
assert (wigner_9j(1, 4, 3,
|
74 |
+
5 * half, 4, 5 * half,
|
75 |
+
5 * half, 2, 7 * half)
|
76 |
+
== -sqrt(Rational(3971, 373403520)))
|
77 |
+
assert (wigner_9j(4, 9 * half, 5 * half,
|
78 |
+
2, 4, 4,
|
79 |
+
5, 7 * half, 7 * half)
|
80 |
+
== -sqrt(Rational(3481, 5042614500)))
|
81 |
+
|
82 |
+
|
83 |
+
def test_gaunt():
|
84 |
+
def tn(a, b):
|
85 |
+
return (a - b).n(64) < S('1e-64')
|
86 |
+
assert gaunt(1, 0, 1, 1, 0, -1) == -1/(2*sqrt(pi))
|
87 |
+
assert isinstance(gaunt(1, 1, 0, -1, 1, 0).args[0], Rational)
|
88 |
+
assert isinstance(gaunt(0, 1, 1, 0, -1, 1).args[0], Rational)
|
89 |
+
|
90 |
+
assert tn(gaunt(
|
91 |
+
10, 10, 12, 9, 3, -12, prec=64), (Rational(-98, 62031)) * sqrt(6279)/sqrt(pi))
|
92 |
+
def gaunt_ref(l1, l2, l3, m1, m2, m3):
|
93 |
+
return (
|
94 |
+
sqrt((2 * l1 + 1) * (2 * l2 + 1) * (2 * l3 + 1) / (4 * pi)) *
|
95 |
+
wigner_3j(l1, l2, l3, 0, 0, 0) *
|
96 |
+
wigner_3j(l1, l2, l3, m1, m2, m3)
|
97 |
+
)
|
98 |
+
threshold = 1e-10
|
99 |
+
l_max = 3
|
100 |
+
l3_max = 24
|
101 |
+
for l1 in range(l_max + 1):
|
102 |
+
for l2 in range(l_max + 1):
|
103 |
+
for l3 in range(l3_max + 1):
|
104 |
+
for m1 in range(-l1, l1 + 1):
|
105 |
+
for m2 in range(-l2, l2 + 1):
|
106 |
+
for m3 in range(-l3, l3 + 1):
|
107 |
+
args = l1, l2, l3, m1, m2, m3
|
108 |
+
g = gaunt(*args)
|
109 |
+
g0 = gaunt_ref(*args)
|
110 |
+
assert abs(g - g0) < threshold
|
111 |
+
if m1 + m2 + m3 != 0:
|
112 |
+
assert abs(g) < threshold
|
113 |
+
if (l1 + l2 + l3) % 2:
|
114 |
+
assert abs(g) < threshold
|
115 |
+
assert gaunt(1, 1, 0, 0, 2, -2) is S.Zero
|
116 |
+
|
117 |
+
|
118 |
+
def test_realgaunt():
|
119 |
+
# All non-zero values corresponding to l values from 0 to 2
|
120 |
+
for l in range(3):
|
121 |
+
for m in range(-l, l+1):
|
122 |
+
assert real_gaunt(0, l, l, 0, m, m) == 1/(2*sqrt(pi))
|
123 |
+
assert real_gaunt(1, 1, 2, 0, 0, 0) == sqrt(5)/(5*sqrt(pi))
|
124 |
+
assert real_gaunt(1, 1, 2, 1, 1, 0) == -sqrt(5)/(10*sqrt(pi))
|
125 |
+
assert real_gaunt(2, 2, 2, 0, 0, 0) == sqrt(5)/(7*sqrt(pi))
|
126 |
+
assert real_gaunt(2, 2, 2, 0, 2, 2) == -sqrt(5)/(7*sqrt(pi))
|
127 |
+
assert real_gaunt(2, 2, 2, -2, -2, 0) == -sqrt(5)/(7*sqrt(pi))
|
128 |
+
assert real_gaunt(1, 1, 2, -1, 0, -1) == sqrt(15)/(10*sqrt(pi))
|
129 |
+
assert real_gaunt(1, 1, 2, 0, 1, 1) == sqrt(15)/(10*sqrt(pi))
|
130 |
+
assert real_gaunt(1, 1, 2, 1, 1, 2) == sqrt(15)/(10*sqrt(pi))
|
131 |
+
assert real_gaunt(1, 1, 2, -1, 1, -2) == -sqrt(15)/(10*sqrt(pi))
|
132 |
+
assert real_gaunt(1, 1, 2, -1, -1, 2) == -sqrt(15)/(10*sqrt(pi))
|
133 |
+
assert real_gaunt(2, 2, 2, 0, 1, 1) == sqrt(5)/(14*sqrt(pi))
|
134 |
+
assert real_gaunt(2, 2, 2, 1, 1, 2) == sqrt(15)/(14*sqrt(pi))
|
135 |
+
assert real_gaunt(2, 2, 2, -1, -1, 2) == -sqrt(15)/(14*sqrt(pi))
|
136 |
+
|
137 |
+
assert real_gaunt(-2, -2, -2, -2, -2, 0) is S.Zero # m test
|
138 |
+
assert real_gaunt(-2, 1, 0, 1, 1, 1) is S.Zero # l test
|
139 |
+
assert real_gaunt(-2, -1, -2, -1, -1, 0) is S.Zero # m and l test
|
140 |
+
assert real_gaunt(-2, -2, -2, -2, -2, -2) is S.Zero # m and k test
|
141 |
+
assert real_gaunt(-2, -1, -2, -1, -1, -1) is S.Zero # m, l and k test
|
142 |
+
|
143 |
+
x = symbols('x', integer=True)
|
144 |
+
v = [0]*6
|
145 |
+
for i in range(len(v)):
|
146 |
+
v[i] = x # non literal ints fail
|
147 |
+
raises(ValueError, lambda: real_gaunt(*v))
|
148 |
+
v[i] = 0
|
149 |
+
|
150 |
+
|
151 |
+
def test_racah():
|
152 |
+
assert racah(3,3,3,3,3,3) == Rational(-1,14)
|
153 |
+
assert racah(2,2,2,2,2,2) == Rational(-3,70)
|
154 |
+
assert racah(7,8,7,1,7,7, prec=4).is_Float
|
155 |
+
assert racah(5.5,7.5,9.5,6.5,8,9) == -719*sqrt(598)/1158924
|
156 |
+
assert abs(racah(5.5,7.5,9.5,6.5,8,9, prec=4) - (-0.01517)) < S('1e-4')
|
157 |
+
|
158 |
+
|
159 |
+
def test_dot_rota_grad_SH():
|
160 |
+
theta, phi = symbols("theta phi")
|
161 |
+
assert dot_rot_grad_Ynm(1, 1, 1, 1, 1, 0) != \
|
162 |
+
sqrt(30)*Ynm(2, 2, 1, 0)/(10*sqrt(pi))
|
163 |
+
assert dot_rot_grad_Ynm(1, 1, 1, 1, 1, 0).doit() == \
|
164 |
+
sqrt(30)*Ynm(2, 2, 1, 0)/(10*sqrt(pi))
|
165 |
+
assert dot_rot_grad_Ynm(1, 5, 1, 1, 1, 2) != \
|
166 |
+
0
|
167 |
+
assert dot_rot_grad_Ynm(1, 5, 1, 1, 1, 2).doit() == \
|
168 |
+
0
|
169 |
+
assert dot_rot_grad_Ynm(3, 3, 3, 3, theta, phi).doit() == \
|
170 |
+
15*sqrt(3003)*Ynm(6, 6, theta, phi)/(143*sqrt(pi))
|
171 |
+
assert dot_rot_grad_Ynm(3, 3, 1, 1, theta, phi).doit() == \
|
172 |
+
sqrt(3)*Ynm(4, 4, theta, phi)/sqrt(pi)
|
173 |
+
assert dot_rot_grad_Ynm(3, 2, 2, 0, theta, phi).doit() == \
|
174 |
+
3*sqrt(55)*Ynm(5, 2, theta, phi)/(11*sqrt(pi))
|
175 |
+
assert dot_rot_grad_Ynm(3, 2, 3, 2, theta, phi).doit().expand() == \
|
176 |
+
-sqrt(70)*Ynm(4, 4, theta, phi)/(11*sqrt(pi)) + \
|
177 |
+
45*sqrt(182)*Ynm(6, 4, theta, phi)/(143*sqrt(pi))
|
178 |
+
|
179 |
+
|
180 |
+
def test_wigner_d():
|
181 |
+
half = S(1)/2
|
182 |
+
alpha, beta, gamma = symbols("alpha, beta, gamma", real=True)
|
183 |
+
d = wigner_d_small(half, beta).subs({beta: pi/2})
|
184 |
+
d_ = Matrix([[1, 1], [-1, 1]])/sqrt(2)
|
185 |
+
assert d == d_
|
186 |
+
|
187 |
+
D = wigner_d(half, alpha, beta, gamma)
|
188 |
+
assert D[0, 0] == exp(I*alpha/2)*exp(I*gamma/2)*cos(beta/2)
|
189 |
+
assert D[0, 1] == exp(I*alpha/2)*exp(-I*gamma/2)*sin(beta/2)
|
190 |
+
assert D[1, 0] == -exp(-I*alpha/2)*exp(I*gamma/2)*sin(beta/2)
|
191 |
+
assert D[1, 1] == exp(-I*alpha/2)*exp(-I*gamma/2)*cos(beta/2)
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/test_hydrogen.py
ADDED
@@ -0,0 +1,126 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.core.numbers import (I, Rational, oo, pi)
|
2 |
+
from sympy.core.singleton import S
|
3 |
+
from sympy.core.symbol import symbols
|
4 |
+
from sympy.functions.elementary.exponential import exp
|
5 |
+
from sympy.functions.elementary.miscellaneous import sqrt
|
6 |
+
from sympy.functions.elementary.trigonometric import (cos, sin)
|
7 |
+
from sympy.integrals.integrals import integrate
|
8 |
+
from sympy.simplify.simplify import simplify
|
9 |
+
from sympy.physics.hydrogen import R_nl, E_nl, E_nl_dirac, Psi_nlm
|
10 |
+
from sympy.testing.pytest import raises
|
11 |
+
|
12 |
+
n, r, Z = symbols('n r Z')
|
13 |
+
|
14 |
+
|
15 |
+
def feq(a, b, max_relative_error=1e-12, max_absolute_error=1e-12):
|
16 |
+
a = float(a)
|
17 |
+
b = float(b)
|
18 |
+
# if the numbers are close enough (absolutely), then they are equal
|
19 |
+
if abs(a - b) < max_absolute_error:
|
20 |
+
return True
|
21 |
+
# if not, they can still be equal if their relative error is small
|
22 |
+
if abs(b) > abs(a):
|
23 |
+
relative_error = abs((a - b)/b)
|
24 |
+
else:
|
25 |
+
relative_error = abs((a - b)/a)
|
26 |
+
return relative_error <= max_relative_error
|
27 |
+
|
28 |
+
|
29 |
+
def test_wavefunction():
|
30 |
+
a = 1/Z
|
31 |
+
R = {
|
32 |
+
(1, 0): 2*sqrt(1/a**3) * exp(-r/a),
|
33 |
+
(2, 0): sqrt(1/(2*a**3)) * exp(-r/(2*a)) * (1 - r/(2*a)),
|
34 |
+
(2, 1): S.Half * sqrt(1/(6*a**3)) * exp(-r/(2*a)) * r/a,
|
35 |
+
(3, 0): Rational(2, 3) * sqrt(1/(3*a**3)) * exp(-r/(3*a)) *
|
36 |
+
(1 - 2*r/(3*a) + Rational(2, 27) * (r/a)**2),
|
37 |
+
(3, 1): Rational(4, 27) * sqrt(2/(3*a**3)) * exp(-r/(3*a)) *
|
38 |
+
(1 - r/(6*a)) * r/a,
|
39 |
+
(3, 2): Rational(2, 81) * sqrt(2/(15*a**3)) * exp(-r/(3*a)) * (r/a)**2,
|
40 |
+
(4, 0): Rational(1, 4) * sqrt(1/a**3) * exp(-r/(4*a)) *
|
41 |
+
(1 - 3*r/(4*a) + Rational(1, 8) * (r/a)**2 - Rational(1, 192) * (r/a)**3),
|
42 |
+
(4, 1): Rational(1, 16) * sqrt(5/(3*a**3)) * exp(-r/(4*a)) *
|
43 |
+
(1 - r/(4*a) + Rational(1, 80) * (r/a)**2) * (r/a),
|
44 |
+
(4, 2): Rational(1, 64) * sqrt(1/(5*a**3)) * exp(-r/(4*a)) *
|
45 |
+
(1 - r/(12*a)) * (r/a)**2,
|
46 |
+
(4, 3): Rational(1, 768) * sqrt(1/(35*a**3)) * exp(-r/(4*a)) * (r/a)**3,
|
47 |
+
}
|
48 |
+
for n, l in R:
|
49 |
+
assert simplify(R_nl(n, l, r, Z) - R[(n, l)]) == 0
|
50 |
+
|
51 |
+
|
52 |
+
def test_norm():
|
53 |
+
# Maximum "n" which is tested:
|
54 |
+
n_max = 2 # it works, but is slow, for n_max > 2
|
55 |
+
for n in range(n_max + 1):
|
56 |
+
for l in range(n):
|
57 |
+
assert integrate(R_nl(n, l, r)**2 * r**2, (r, 0, oo)) == 1
|
58 |
+
|
59 |
+
def test_psi_nlm():
|
60 |
+
r=S('r')
|
61 |
+
phi=S('phi')
|
62 |
+
theta=S('theta')
|
63 |
+
assert (Psi_nlm(1, 0, 0, r, phi, theta) == exp(-r) / sqrt(pi))
|
64 |
+
assert (Psi_nlm(2, 1, -1, r, phi, theta)) == S.Half * exp(-r / (2)) * r \
|
65 |
+
* (sin(theta) * exp(-I * phi) / (4 * sqrt(pi)))
|
66 |
+
assert (Psi_nlm(3, 2, 1, r, phi, theta, 2) == -sqrt(2) * sin(theta) \
|
67 |
+
* exp(I * phi) * cos(theta) / (4 * sqrt(pi)) * S(2) / 81 \
|
68 |
+
* sqrt(2 * 2 ** 3) * exp(-2 * r / (3)) * (r * 2) ** 2)
|
69 |
+
|
70 |
+
def test_hydrogen_energies():
|
71 |
+
assert E_nl(n, Z) == -Z**2/(2*n**2)
|
72 |
+
assert E_nl(n) == -1/(2*n**2)
|
73 |
+
|
74 |
+
assert E_nl(1, 47) == -S(47)**2/(2*1**2)
|
75 |
+
assert E_nl(2, 47) == -S(47)**2/(2*2**2)
|
76 |
+
|
77 |
+
assert E_nl(1) == -S.One/(2*1**2)
|
78 |
+
assert E_nl(2) == -S.One/(2*2**2)
|
79 |
+
assert E_nl(3) == -S.One/(2*3**2)
|
80 |
+
assert E_nl(4) == -S.One/(2*4**2)
|
81 |
+
assert E_nl(100) == -S.One/(2*100**2)
|
82 |
+
|
83 |
+
raises(ValueError, lambda: E_nl(0))
|
84 |
+
|
85 |
+
|
86 |
+
def test_hydrogen_energies_relat():
|
87 |
+
# First test exact formulas for small "c" so that we get nice expressions:
|
88 |
+
assert E_nl_dirac(2, 0, Z=1, c=1) == 1/sqrt(2) - 1
|
89 |
+
assert simplify(E_nl_dirac(2, 0, Z=1, c=2) - ( (8*sqrt(3) + 16)
|
90 |
+
/ sqrt(16*sqrt(3) + 32) - 4)) == 0
|
91 |
+
assert simplify(E_nl_dirac(2, 0, Z=1, c=3) - ( (54*sqrt(2) + 81)
|
92 |
+
/ sqrt(108*sqrt(2) + 162) - 9)) == 0
|
93 |
+
|
94 |
+
# Now test for almost the correct speed of light, without floating point
|
95 |
+
# numbers:
|
96 |
+
assert simplify(E_nl_dirac(2, 0, Z=1, c=137) - ( (352275361 + 10285412 *
|
97 |
+
sqrt(1173)) / sqrt(704550722 + 20570824 * sqrt(1173)) - 18769)) == 0
|
98 |
+
assert simplify(E_nl_dirac(2, 0, Z=82, c=137) - ( (352275361 + 2571353 *
|
99 |
+
sqrt(12045)) / sqrt(704550722 + 5142706*sqrt(12045)) - 18769)) == 0
|
100 |
+
|
101 |
+
# Test using exact speed of light, and compare against the nonrelativistic
|
102 |
+
# energies:
|
103 |
+
for n in range(1, 5):
|
104 |
+
for l in range(n):
|
105 |
+
assert feq(E_nl_dirac(n, l), E_nl(n), 1e-5, 1e-5)
|
106 |
+
if l > 0:
|
107 |
+
assert feq(E_nl_dirac(n, l, False), E_nl(n), 1e-5, 1e-5)
|
108 |
+
|
109 |
+
Z = 2
|
110 |
+
for n in range(1, 5):
|
111 |
+
for l in range(n):
|
112 |
+
assert feq(E_nl_dirac(n, l, Z=Z), E_nl(n, Z), 1e-4, 1e-4)
|
113 |
+
if l > 0:
|
114 |
+
assert feq(E_nl_dirac(n, l, False, Z), E_nl(n, Z), 1e-4, 1e-4)
|
115 |
+
|
116 |
+
Z = 3
|
117 |
+
for n in range(1, 5):
|
118 |
+
for l in range(n):
|
119 |
+
assert feq(E_nl_dirac(n, l, Z=Z), E_nl(n, Z), 1e-3, 1e-3)
|
120 |
+
if l > 0:
|
121 |
+
assert feq(E_nl_dirac(n, l, False, Z), E_nl(n, Z), 1e-3, 1e-3)
|
122 |
+
|
123 |
+
# Test the exceptions:
|
124 |
+
raises(ValueError, lambda: E_nl_dirac(0, 0))
|
125 |
+
raises(ValueError, lambda: E_nl_dirac(1, -1))
|
126 |
+
raises(ValueError, lambda: E_nl_dirac(1, 0, False))
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/test_paulialgebra.py
ADDED
@@ -0,0 +1,57 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.core.numbers import I
|
2 |
+
from sympy.core.symbol import symbols
|
3 |
+
from sympy.physics.paulialgebra import Pauli
|
4 |
+
from sympy.testing.pytest import XFAIL
|
5 |
+
from sympy.physics.quantum import TensorProduct
|
6 |
+
|
7 |
+
sigma1 = Pauli(1)
|
8 |
+
sigma2 = Pauli(2)
|
9 |
+
sigma3 = Pauli(3)
|
10 |
+
|
11 |
+
tau1 = symbols("tau1", commutative = False)
|
12 |
+
|
13 |
+
|
14 |
+
def test_Pauli():
|
15 |
+
|
16 |
+
assert sigma1 == sigma1
|
17 |
+
assert sigma1 != sigma2
|
18 |
+
|
19 |
+
assert sigma1*sigma2 == I*sigma3
|
20 |
+
assert sigma3*sigma1 == I*sigma2
|
21 |
+
assert sigma2*sigma3 == I*sigma1
|
22 |
+
|
23 |
+
assert sigma1*sigma1 == 1
|
24 |
+
assert sigma2*sigma2 == 1
|
25 |
+
assert sigma3*sigma3 == 1
|
26 |
+
|
27 |
+
assert sigma1**0 == 1
|
28 |
+
assert sigma1**1 == sigma1
|
29 |
+
assert sigma1**2 == 1
|
30 |
+
assert sigma1**3 == sigma1
|
31 |
+
assert sigma1**4 == 1
|
32 |
+
|
33 |
+
assert sigma3**2 == 1
|
34 |
+
|
35 |
+
assert sigma1*2*sigma1 == 2
|
36 |
+
|
37 |
+
|
38 |
+
def test_evaluate_pauli_product():
|
39 |
+
from sympy.physics.paulialgebra import evaluate_pauli_product
|
40 |
+
|
41 |
+
assert evaluate_pauli_product(I*sigma2*sigma3) == -sigma1
|
42 |
+
|
43 |
+
# Check issue 6471
|
44 |
+
assert evaluate_pauli_product(-I*4*sigma1*sigma2) == 4*sigma3
|
45 |
+
|
46 |
+
assert evaluate_pauli_product(
|
47 |
+
1 + I*sigma1*sigma2*sigma1*sigma2 + \
|
48 |
+
I*sigma1*sigma2*tau1*sigma1*sigma3 + \
|
49 |
+
((tau1**2).subs(tau1, I*sigma1)) + \
|
50 |
+
sigma3*((tau1**2).subs(tau1, I*sigma1)) + \
|
51 |
+
TensorProduct(I*sigma1*sigma2*sigma1*sigma2, 1)
|
52 |
+
) == 1 -I + I*sigma3*tau1*sigma2 - 1 - sigma3 - I*TensorProduct(1,1)
|
53 |
+
|
54 |
+
|
55 |
+
@XFAIL
|
56 |
+
def test_Pauli_should_work():
|
57 |
+
assert sigma1*sigma3*sigma1 == -sigma3
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/test_physics_matrices.py
ADDED
@@ -0,0 +1,84 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.physics.matrices import msigma, mgamma, minkowski_tensor, pat_matrix, mdft
|
2 |
+
from sympy.core.numbers import (I, Rational)
|
3 |
+
from sympy.core.singleton import S
|
4 |
+
from sympy.functions.elementary.miscellaneous import sqrt
|
5 |
+
from sympy.matrices.dense import (Matrix, eye, zeros)
|
6 |
+
from sympy.testing.pytest import warns_deprecated_sympy
|
7 |
+
|
8 |
+
|
9 |
+
def test_parallel_axis_theorem():
|
10 |
+
# This tests the parallel axis theorem matrix by comparing to test
|
11 |
+
# matrices.
|
12 |
+
|
13 |
+
# First case, 1 in all directions.
|
14 |
+
mat1 = Matrix(((2, -1, -1), (-1, 2, -1), (-1, -1, 2)))
|
15 |
+
assert pat_matrix(1, 1, 1, 1) == mat1
|
16 |
+
assert pat_matrix(2, 1, 1, 1) == 2*mat1
|
17 |
+
|
18 |
+
# Second case, 1 in x, 0 in all others
|
19 |
+
mat2 = Matrix(((0, 0, 0), (0, 1, 0), (0, 0, 1)))
|
20 |
+
assert pat_matrix(1, 1, 0, 0) == mat2
|
21 |
+
assert pat_matrix(2, 1, 0, 0) == 2*mat2
|
22 |
+
|
23 |
+
# Third case, 1 in y, 0 in all others
|
24 |
+
mat3 = Matrix(((1, 0, 0), (0, 0, 0), (0, 0, 1)))
|
25 |
+
assert pat_matrix(1, 0, 1, 0) == mat3
|
26 |
+
assert pat_matrix(2, 0, 1, 0) == 2*mat3
|
27 |
+
|
28 |
+
# Fourth case, 1 in z, 0 in all others
|
29 |
+
mat4 = Matrix(((1, 0, 0), (0, 1, 0), (0, 0, 0)))
|
30 |
+
assert pat_matrix(1, 0, 0, 1) == mat4
|
31 |
+
assert pat_matrix(2, 0, 0, 1) == 2*mat4
|
32 |
+
|
33 |
+
|
34 |
+
def test_Pauli():
|
35 |
+
#this and the following test are testing both Pauli and Dirac matrices
|
36 |
+
#and also that the general Matrix class works correctly in a real world
|
37 |
+
#situation
|
38 |
+
sigma1 = msigma(1)
|
39 |
+
sigma2 = msigma(2)
|
40 |
+
sigma3 = msigma(3)
|
41 |
+
|
42 |
+
assert sigma1 == sigma1
|
43 |
+
assert sigma1 != sigma2
|
44 |
+
|
45 |
+
# sigma*I -> I*sigma (see #354)
|
46 |
+
assert sigma1*sigma2 == sigma3*I
|
47 |
+
assert sigma3*sigma1 == sigma2*I
|
48 |
+
assert sigma2*sigma3 == sigma1*I
|
49 |
+
|
50 |
+
assert sigma1*sigma1 == eye(2)
|
51 |
+
assert sigma2*sigma2 == eye(2)
|
52 |
+
assert sigma3*sigma3 == eye(2)
|
53 |
+
|
54 |
+
assert sigma1*2*sigma1 == 2*eye(2)
|
55 |
+
assert sigma1*sigma3*sigma1 == -sigma3
|
56 |
+
|
57 |
+
|
58 |
+
def test_Dirac():
|
59 |
+
gamma0 = mgamma(0)
|
60 |
+
gamma1 = mgamma(1)
|
61 |
+
gamma2 = mgamma(2)
|
62 |
+
gamma3 = mgamma(3)
|
63 |
+
gamma5 = mgamma(5)
|
64 |
+
|
65 |
+
# gamma*I -> I*gamma (see #354)
|
66 |
+
assert gamma5 == gamma0 * gamma1 * gamma2 * gamma3 * I
|
67 |
+
assert gamma1 * gamma2 + gamma2 * gamma1 == zeros(4)
|
68 |
+
assert gamma0 * gamma0 == eye(4) * minkowski_tensor[0, 0]
|
69 |
+
assert gamma2 * gamma2 != eye(4) * minkowski_tensor[0, 0]
|
70 |
+
assert gamma2 * gamma2 == eye(4) * minkowski_tensor[2, 2]
|
71 |
+
|
72 |
+
assert mgamma(5, True) == \
|
73 |
+
mgamma(0, True)*mgamma(1, True)*mgamma(2, True)*mgamma(3, True)*I
|
74 |
+
|
75 |
+
def test_mdft():
|
76 |
+
with warns_deprecated_sympy():
|
77 |
+
assert mdft(1) == Matrix([[1]])
|
78 |
+
with warns_deprecated_sympy():
|
79 |
+
assert mdft(2) == 1/sqrt(2)*Matrix([[1,1],[1,-1]])
|
80 |
+
with warns_deprecated_sympy():
|
81 |
+
assert mdft(4) == Matrix([[S.Half, S.Half, S.Half, S.Half],
|
82 |
+
[S.Half, -I/2, Rational(-1,2), I/2],
|
83 |
+
[S.Half, Rational(-1,2), S.Half, Rational(-1,2)],
|
84 |
+
[S.Half, I/2, Rational(-1,2), -I/2]])
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/test_pring.py
ADDED
@@ -0,0 +1,41 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.physics.pring import wavefunction, energy
|
2 |
+
from sympy.core.numbers import (I, pi)
|
3 |
+
from sympy.functions.elementary.exponential import exp
|
4 |
+
from sympy.functions.elementary.miscellaneous import sqrt
|
5 |
+
from sympy.integrals.integrals import integrate
|
6 |
+
from sympy.simplify.simplify import simplify
|
7 |
+
from sympy.abc import m, x, r
|
8 |
+
from sympy.physics.quantum.constants import hbar
|
9 |
+
|
10 |
+
|
11 |
+
def test_wavefunction():
|
12 |
+
Psi = {
|
13 |
+
0: (1/sqrt(2 * pi)),
|
14 |
+
1: (1/sqrt(2 * pi)) * exp(I * x),
|
15 |
+
2: (1/sqrt(2 * pi)) * exp(2 * I * x),
|
16 |
+
3: (1/sqrt(2 * pi)) * exp(3 * I * x)
|
17 |
+
}
|
18 |
+
for n in Psi:
|
19 |
+
assert simplify(wavefunction(n, x) - Psi[n]) == 0
|
20 |
+
|
21 |
+
|
22 |
+
def test_norm(n=1):
|
23 |
+
# Maximum "n" which is tested:
|
24 |
+
for i in range(n + 1):
|
25 |
+
assert integrate(
|
26 |
+
wavefunction(i, x) * wavefunction(-i, x), (x, 0, 2 * pi)) == 1
|
27 |
+
|
28 |
+
|
29 |
+
def test_orthogonality(n=1):
|
30 |
+
# Maximum "n" which is tested:
|
31 |
+
for i in range(n + 1):
|
32 |
+
for j in range(i+1, n+1):
|
33 |
+
assert integrate(
|
34 |
+
wavefunction(i, x) * wavefunction(j, x), (x, 0, 2 * pi)) == 0
|
35 |
+
|
36 |
+
|
37 |
+
def test_energy(n=1):
|
38 |
+
# Maximum "n" which is tested:
|
39 |
+
for i in range(n+1):
|
40 |
+
assert simplify(
|
41 |
+
energy(i, m, r) - ((i**2 * hbar**2) / (2 * m * r**2))) == 0
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/test_qho_1d.py
ADDED
@@ -0,0 +1,50 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.core.numbers import (Rational, oo, pi)
|
2 |
+
from sympy.core.singleton import S
|
3 |
+
from sympy.core.symbol import Symbol
|
4 |
+
from sympy.functions.elementary.exponential import exp
|
5 |
+
from sympy.functions.elementary.miscellaneous import sqrt
|
6 |
+
from sympy.integrals.integrals import integrate
|
7 |
+
from sympy.simplify.simplify import simplify
|
8 |
+
from sympy.abc import omega, m, x
|
9 |
+
from sympy.physics.qho_1d import psi_n, E_n, coherent_state
|
10 |
+
from sympy.physics.quantum.constants import hbar
|
11 |
+
|
12 |
+
nu = m * omega / hbar
|
13 |
+
|
14 |
+
|
15 |
+
def test_wavefunction():
|
16 |
+
Psi = {
|
17 |
+
0: (nu/pi)**Rational(1, 4) * exp(-nu * x**2 /2),
|
18 |
+
1: (nu/pi)**Rational(1, 4) * sqrt(2*nu) * x * exp(-nu * x**2 /2),
|
19 |
+
2: (nu/pi)**Rational(1, 4) * (2 * nu * x**2 - 1)/sqrt(2) * exp(-nu * x**2 /2),
|
20 |
+
3: (nu/pi)**Rational(1, 4) * sqrt(nu/3) * (2 * nu * x**3 - 3 * x) * exp(-nu * x**2 /2)
|
21 |
+
}
|
22 |
+
for n in Psi:
|
23 |
+
assert simplify(psi_n(n, x, m, omega) - Psi[n]) == 0
|
24 |
+
|
25 |
+
|
26 |
+
def test_norm(n=1):
|
27 |
+
# Maximum "n" which is tested:
|
28 |
+
for i in range(n + 1):
|
29 |
+
assert integrate(psi_n(i, x, 1, 1)**2, (x, -oo, oo)) == 1
|
30 |
+
|
31 |
+
|
32 |
+
def test_orthogonality(n=1):
|
33 |
+
# Maximum "n" which is tested:
|
34 |
+
for i in range(n + 1):
|
35 |
+
for j in range(i + 1, n + 1):
|
36 |
+
assert integrate(
|
37 |
+
psi_n(i, x, 1, 1)*psi_n(j, x, 1, 1), (x, -oo, oo)) == 0
|
38 |
+
|
39 |
+
|
40 |
+
def test_energies(n=1):
|
41 |
+
# Maximum "n" which is tested:
|
42 |
+
for i in range(n + 1):
|
43 |
+
assert E_n(i, omega) == hbar * omega * (i + S.Half)
|
44 |
+
|
45 |
+
def test_coherent_state(n=10):
|
46 |
+
# Maximum "n" which is tested:
|
47 |
+
# test whether coherent state is the eigenstate of annihilation operator
|
48 |
+
alpha = Symbol("alpha")
|
49 |
+
for i in range(n + 1):
|
50 |
+
assert simplify(sqrt(n + 1) * coherent_state(n + 1, alpha)) == simplify(alpha * coherent_state(n, alpha))
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/test_secondquant.py
ADDED
@@ -0,0 +1,1280 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.physics.secondquant import (
|
2 |
+
Dagger, Bd, VarBosonicBasis, BBra, B, BKet, FixedBosonicBasis,
|
3 |
+
matrix_rep, apply_operators, InnerProduct, Commutator, KroneckerDelta,
|
4 |
+
AnnihilateBoson, CreateBoson, BosonicOperator,
|
5 |
+
F, Fd, FKet, BosonState, CreateFermion, AnnihilateFermion,
|
6 |
+
evaluate_deltas, AntiSymmetricTensor, contraction, NO, wicks,
|
7 |
+
PermutationOperator, simplify_index_permutations,
|
8 |
+
_sort_anticommuting_fermions, _get_ordered_dummies,
|
9 |
+
substitute_dummies, FockStateBosonKet,
|
10 |
+
ContractionAppliesOnlyToFermions
|
11 |
+
)
|
12 |
+
|
13 |
+
from sympy.concrete.summations import Sum
|
14 |
+
from sympy.core.function import (Function, expand)
|
15 |
+
from sympy.core.numbers import (I, Rational)
|
16 |
+
from sympy.core.singleton import S
|
17 |
+
from sympy.core.symbol import (Dummy, Symbol, symbols)
|
18 |
+
from sympy.functions.elementary.miscellaneous import sqrt
|
19 |
+
from sympy.printing.repr import srepr
|
20 |
+
from sympy.simplify.simplify import simplify
|
21 |
+
|
22 |
+
from sympy.testing.pytest import slow, raises
|
23 |
+
from sympy.printing.latex import latex
|
24 |
+
|
25 |
+
|
26 |
+
def test_PermutationOperator():
|
27 |
+
p, q, r, s = symbols('p,q,r,s')
|
28 |
+
f, g, h, i = map(Function, 'fghi')
|
29 |
+
P = PermutationOperator
|
30 |
+
assert P(p, q).get_permuted(f(p)*g(q)) == -f(q)*g(p)
|
31 |
+
assert P(p, q).get_permuted(f(p, q)) == -f(q, p)
|
32 |
+
assert P(p, q).get_permuted(f(p)) == f(p)
|
33 |
+
expr = (f(p)*g(q)*h(r)*i(s)
|
34 |
+
- f(q)*g(p)*h(r)*i(s)
|
35 |
+
- f(p)*g(q)*h(s)*i(r)
|
36 |
+
+ f(q)*g(p)*h(s)*i(r))
|
37 |
+
perms = [P(p, q), P(r, s)]
|
38 |
+
assert (simplify_index_permutations(expr, perms) ==
|
39 |
+
P(p, q)*P(r, s)*f(p)*g(q)*h(r)*i(s))
|
40 |
+
assert latex(P(p, q)) == 'P(pq)'
|
41 |
+
|
42 |
+
|
43 |
+
def test_index_permutations_with_dummies():
|
44 |
+
a, b, c, d = symbols('a b c d')
|
45 |
+
p, q, r, s = symbols('p q r s', cls=Dummy)
|
46 |
+
f, g = map(Function, 'fg')
|
47 |
+
P = PermutationOperator
|
48 |
+
|
49 |
+
# No dummy substitution necessary
|
50 |
+
expr = f(a, b, p, q) - f(b, a, p, q)
|
51 |
+
assert simplify_index_permutations(
|
52 |
+
expr, [P(a, b)]) == P(a, b)*f(a, b, p, q)
|
53 |
+
|
54 |
+
# Cases where dummy substitution is needed
|
55 |
+
expected = P(a, b)*substitute_dummies(f(a, b, p, q))
|
56 |
+
|
57 |
+
expr = f(a, b, p, q) - f(b, a, q, p)
|
58 |
+
result = simplify_index_permutations(expr, [P(a, b)])
|
59 |
+
assert expected == substitute_dummies(result)
|
60 |
+
|
61 |
+
expr = f(a, b, q, p) - f(b, a, p, q)
|
62 |
+
result = simplify_index_permutations(expr, [P(a, b)])
|
63 |
+
assert expected == substitute_dummies(result)
|
64 |
+
|
65 |
+
# A case where nothing can be done
|
66 |
+
expr = f(a, b, q, p) - g(b, a, p, q)
|
67 |
+
result = simplify_index_permutations(expr, [P(a, b)])
|
68 |
+
assert expr == result
|
69 |
+
|
70 |
+
|
71 |
+
def test_dagger():
|
72 |
+
i, j, n, m = symbols('i,j,n,m')
|
73 |
+
assert Dagger(1) == 1
|
74 |
+
assert Dagger(1.0) == 1.0
|
75 |
+
assert Dagger(2*I) == -2*I
|
76 |
+
assert Dagger(S.Half*I/3.0) == I*Rational(-1, 2)/3.0
|
77 |
+
assert Dagger(BKet([n])) == BBra([n])
|
78 |
+
assert Dagger(B(0)) == Bd(0)
|
79 |
+
assert Dagger(Bd(0)) == B(0)
|
80 |
+
assert Dagger(B(n)) == Bd(n)
|
81 |
+
assert Dagger(Bd(n)) == B(n)
|
82 |
+
assert Dagger(B(0) + B(1)) == Bd(0) + Bd(1)
|
83 |
+
assert Dagger(n*m) == Dagger(n)*Dagger(m) # n, m commute
|
84 |
+
assert Dagger(B(n)*B(m)) == Bd(m)*Bd(n)
|
85 |
+
assert Dagger(B(n)**10) == Dagger(B(n))**10
|
86 |
+
assert Dagger('a') == Dagger(Symbol('a'))
|
87 |
+
assert Dagger(Dagger('a')) == Symbol('a')
|
88 |
+
|
89 |
+
|
90 |
+
def test_operator():
|
91 |
+
i, j = symbols('i,j')
|
92 |
+
o = BosonicOperator(i)
|
93 |
+
assert o.state == i
|
94 |
+
assert o.is_symbolic
|
95 |
+
o = BosonicOperator(1)
|
96 |
+
assert o.state == 1
|
97 |
+
assert not o.is_symbolic
|
98 |
+
|
99 |
+
|
100 |
+
def test_create():
|
101 |
+
i, j, n, m = symbols('i,j,n,m')
|
102 |
+
o = Bd(i)
|
103 |
+
assert latex(o) == "{b^\\dagger_{i}}"
|
104 |
+
assert isinstance(o, CreateBoson)
|
105 |
+
o = o.subs(i, j)
|
106 |
+
assert o.atoms(Symbol) == {j}
|
107 |
+
o = Bd(0)
|
108 |
+
assert o.apply_operator(BKet([n])) == sqrt(n + 1)*BKet([n + 1])
|
109 |
+
o = Bd(n)
|
110 |
+
assert o.apply_operator(BKet([n])) == o*BKet([n])
|
111 |
+
|
112 |
+
|
113 |
+
def test_annihilate():
|
114 |
+
i, j, n, m = symbols('i,j,n,m')
|
115 |
+
o = B(i)
|
116 |
+
assert latex(o) == "b_{i}"
|
117 |
+
assert isinstance(o, AnnihilateBoson)
|
118 |
+
o = o.subs(i, j)
|
119 |
+
assert o.atoms(Symbol) == {j}
|
120 |
+
o = B(0)
|
121 |
+
assert o.apply_operator(BKet([n])) == sqrt(n)*BKet([n - 1])
|
122 |
+
o = B(n)
|
123 |
+
assert o.apply_operator(BKet([n])) == o*BKet([n])
|
124 |
+
|
125 |
+
|
126 |
+
def test_basic_state():
|
127 |
+
i, j, n, m = symbols('i,j,n,m')
|
128 |
+
s = BosonState([0, 1, 2, 3, 4])
|
129 |
+
assert len(s) == 5
|
130 |
+
assert s.args[0] == tuple(range(5))
|
131 |
+
assert s.up(0) == BosonState([1, 1, 2, 3, 4])
|
132 |
+
assert s.down(4) == BosonState([0, 1, 2, 3, 3])
|
133 |
+
for i in range(5):
|
134 |
+
assert s.up(i).down(i) == s
|
135 |
+
assert s.down(0) == 0
|
136 |
+
for i in range(5):
|
137 |
+
assert s[i] == i
|
138 |
+
s = BosonState([n, m])
|
139 |
+
assert s.down(0) == BosonState([n - 1, m])
|
140 |
+
assert s.up(0) == BosonState([n + 1, m])
|
141 |
+
|
142 |
+
|
143 |
+
def test_basic_apply():
|
144 |
+
n = symbols("n")
|
145 |
+
e = B(0)*BKet([n])
|
146 |
+
assert apply_operators(e) == sqrt(n)*BKet([n - 1])
|
147 |
+
e = Bd(0)*BKet([n])
|
148 |
+
assert apply_operators(e) == sqrt(n + 1)*BKet([n + 1])
|
149 |
+
|
150 |
+
|
151 |
+
def test_complex_apply():
|
152 |
+
n, m = symbols("n,m")
|
153 |
+
o = Bd(0)*B(0)*Bd(1)*B(0)
|
154 |
+
e = apply_operators(o*BKet([n, m]))
|
155 |
+
answer = sqrt(n)*sqrt(m + 1)*(-1 + n)*BKet([-1 + n, 1 + m])
|
156 |
+
assert expand(e) == expand(answer)
|
157 |
+
|
158 |
+
|
159 |
+
def test_number_operator():
|
160 |
+
n = symbols("n")
|
161 |
+
o = Bd(0)*B(0)
|
162 |
+
e = apply_operators(o*BKet([n]))
|
163 |
+
assert e == n*BKet([n])
|
164 |
+
|
165 |
+
|
166 |
+
def test_inner_product():
|
167 |
+
i, j, k, l = symbols('i,j,k,l')
|
168 |
+
s1 = BBra([0])
|
169 |
+
s2 = BKet([1])
|
170 |
+
assert InnerProduct(s1, Dagger(s1)) == 1
|
171 |
+
assert InnerProduct(s1, s2) == 0
|
172 |
+
s1 = BBra([i, j])
|
173 |
+
s2 = BKet([k, l])
|
174 |
+
r = InnerProduct(s1, s2)
|
175 |
+
assert r == KroneckerDelta(i, k)*KroneckerDelta(j, l)
|
176 |
+
|
177 |
+
|
178 |
+
def test_symbolic_matrix_elements():
|
179 |
+
n, m = symbols('n,m')
|
180 |
+
s1 = BBra([n])
|
181 |
+
s2 = BKet([m])
|
182 |
+
o = B(0)
|
183 |
+
e = apply_operators(s1*o*s2)
|
184 |
+
assert e == sqrt(m)*KroneckerDelta(n, m - 1)
|
185 |
+
|
186 |
+
|
187 |
+
def test_matrix_elements():
|
188 |
+
b = VarBosonicBasis(5)
|
189 |
+
o = B(0)
|
190 |
+
m = matrix_rep(o, b)
|
191 |
+
for i in range(4):
|
192 |
+
assert m[i, i + 1] == sqrt(i + 1)
|
193 |
+
o = Bd(0)
|
194 |
+
m = matrix_rep(o, b)
|
195 |
+
for i in range(4):
|
196 |
+
assert m[i + 1, i] == sqrt(i + 1)
|
197 |
+
|
198 |
+
|
199 |
+
def test_fixed_bosonic_basis():
|
200 |
+
b = FixedBosonicBasis(2, 2)
|
201 |
+
# assert b == [FockState((2, 0)), FockState((1, 1)), FockState((0, 2))]
|
202 |
+
state = b.state(1)
|
203 |
+
assert state == FockStateBosonKet((1, 1))
|
204 |
+
assert b.index(state) == 1
|
205 |
+
assert b.state(1) == b[1]
|
206 |
+
assert len(b) == 3
|
207 |
+
assert str(b) == '[FockState((2, 0)), FockState((1, 1)), FockState((0, 2))]'
|
208 |
+
assert repr(b) == '[FockState((2, 0)), FockState((1, 1)), FockState((0, 2))]'
|
209 |
+
assert srepr(b) == '[FockState((2, 0)), FockState((1, 1)), FockState((0, 2))]'
|
210 |
+
|
211 |
+
|
212 |
+
@slow
|
213 |
+
def test_sho():
|
214 |
+
n, m = symbols('n,m')
|
215 |
+
h_n = Bd(n)*B(n)*(n + S.Half)
|
216 |
+
H = Sum(h_n, (n, 0, 5))
|
217 |
+
o = H.doit(deep=False)
|
218 |
+
b = FixedBosonicBasis(2, 6)
|
219 |
+
m = matrix_rep(o, b)
|
220 |
+
# We need to double check these energy values to make sure that they
|
221 |
+
# are correct and have the proper degeneracies!
|
222 |
+
diag = [1, 2, 3, 3, 4, 5, 4, 5, 6, 7, 5, 6, 7, 8, 9, 6, 7, 8, 9, 10, 11]
|
223 |
+
for i in range(len(diag)):
|
224 |
+
assert diag[i] == m[i, i]
|
225 |
+
|
226 |
+
|
227 |
+
def test_commutation():
|
228 |
+
n, m = symbols("n,m", above_fermi=True)
|
229 |
+
c = Commutator(B(0), Bd(0))
|
230 |
+
assert c == 1
|
231 |
+
c = Commutator(Bd(0), B(0))
|
232 |
+
assert c == -1
|
233 |
+
c = Commutator(B(n), Bd(0))
|
234 |
+
assert c == KroneckerDelta(n, 0)
|
235 |
+
c = Commutator(B(0), B(0))
|
236 |
+
assert c == 0
|
237 |
+
c = Commutator(B(0), Bd(0))
|
238 |
+
e = simplify(apply_operators(c*BKet([n])))
|
239 |
+
assert e == BKet([n])
|
240 |
+
c = Commutator(B(0), B(1))
|
241 |
+
e = simplify(apply_operators(c*BKet([n, m])))
|
242 |
+
assert e == 0
|
243 |
+
|
244 |
+
c = Commutator(F(m), Fd(m))
|
245 |
+
assert c == +1 - 2*NO(Fd(m)*F(m))
|
246 |
+
c = Commutator(Fd(m), F(m))
|
247 |
+
assert c.expand() == -1 + 2*NO(Fd(m)*F(m))
|
248 |
+
|
249 |
+
C = Commutator
|
250 |
+
X, Y, Z = symbols('X,Y,Z', commutative=False)
|
251 |
+
assert C(C(X, Y), Z) != 0
|
252 |
+
assert C(C(X, Z), Y) != 0
|
253 |
+
assert C(Y, C(X, Z)) != 0
|
254 |
+
|
255 |
+
i, j, k, l = symbols('i,j,k,l', below_fermi=True)
|
256 |
+
a, b, c, d = symbols('a,b,c,d', above_fermi=True)
|
257 |
+
p, q, r, s = symbols('p,q,r,s')
|
258 |
+
D = KroneckerDelta
|
259 |
+
|
260 |
+
assert C(Fd(a), F(i)) == -2*NO(F(i)*Fd(a))
|
261 |
+
assert C(Fd(j), NO(Fd(a)*F(i))).doit(wicks=True) == -D(j, i)*Fd(a)
|
262 |
+
assert C(Fd(a)*F(i), Fd(b)*F(j)).doit(wicks=True) == 0
|
263 |
+
|
264 |
+
c1 = Commutator(F(a), Fd(a))
|
265 |
+
assert Commutator.eval(c1, c1) == 0
|
266 |
+
c = Commutator(Fd(a)*F(i),Fd(b)*F(j))
|
267 |
+
assert latex(c) == r'\left[{a^\dagger_{a}} a_{i},{a^\dagger_{b}} a_{j}\right]'
|
268 |
+
assert repr(c) == 'Commutator(CreateFermion(a)*AnnihilateFermion(i),CreateFermion(b)*AnnihilateFermion(j))'
|
269 |
+
assert str(c) == '[CreateFermion(a)*AnnihilateFermion(i),CreateFermion(b)*AnnihilateFermion(j)]'
|
270 |
+
|
271 |
+
|
272 |
+
def test_create_f():
|
273 |
+
i, j, n, m = symbols('i,j,n,m')
|
274 |
+
o = Fd(i)
|
275 |
+
assert isinstance(o, CreateFermion)
|
276 |
+
o = o.subs(i, j)
|
277 |
+
assert o.atoms(Symbol) == {j}
|
278 |
+
o = Fd(1)
|
279 |
+
assert o.apply_operator(FKet([n])) == FKet([1, n])
|
280 |
+
assert o.apply_operator(FKet([n])) == -FKet([n, 1])
|
281 |
+
o = Fd(n)
|
282 |
+
assert o.apply_operator(FKet([])) == FKet([n])
|
283 |
+
|
284 |
+
vacuum = FKet([], fermi_level=4)
|
285 |
+
assert vacuum == FKet([], fermi_level=4)
|
286 |
+
|
287 |
+
i, j, k, l = symbols('i,j,k,l', below_fermi=True)
|
288 |
+
a, b, c, d = symbols('a,b,c,d', above_fermi=True)
|
289 |
+
p, q, r, s = symbols('p,q,r,s')
|
290 |
+
|
291 |
+
assert Fd(i).apply_operator(FKet([i, j, k], 4)) == FKet([j, k], 4)
|
292 |
+
assert Fd(a).apply_operator(FKet([i, b, k], 4)) == FKet([a, i, b, k], 4)
|
293 |
+
|
294 |
+
assert Dagger(B(p)).apply_operator(q) == q*CreateBoson(p)
|
295 |
+
assert repr(Fd(p)) == 'CreateFermion(p)'
|
296 |
+
assert srepr(Fd(p)) == "CreateFermion(Symbol('p'))"
|
297 |
+
assert latex(Fd(p)) == r'{a^\dagger_{p}}'
|
298 |
+
|
299 |
+
|
300 |
+
def test_annihilate_f():
|
301 |
+
i, j, n, m = symbols('i,j,n,m')
|
302 |
+
o = F(i)
|
303 |
+
assert isinstance(o, AnnihilateFermion)
|
304 |
+
o = o.subs(i, j)
|
305 |
+
assert o.atoms(Symbol) == {j}
|
306 |
+
o = F(1)
|
307 |
+
assert o.apply_operator(FKet([1, n])) == FKet([n])
|
308 |
+
assert o.apply_operator(FKet([n, 1])) == -FKet([n])
|
309 |
+
o = F(n)
|
310 |
+
assert o.apply_operator(FKet([n])) == FKet([])
|
311 |
+
|
312 |
+
i, j, k, l = symbols('i,j,k,l', below_fermi=True)
|
313 |
+
a, b, c, d = symbols('a,b,c,d', above_fermi=True)
|
314 |
+
p, q, r, s = symbols('p,q,r,s')
|
315 |
+
assert F(i).apply_operator(FKet([i, j, k], 4)) == 0
|
316 |
+
assert F(a).apply_operator(FKet([i, b, k], 4)) == 0
|
317 |
+
assert F(l).apply_operator(FKet([i, j, k], 3)) == 0
|
318 |
+
assert F(l).apply_operator(FKet([i, j, k], 4)) == FKet([l, i, j, k], 4)
|
319 |
+
assert str(F(p)) == 'f(p)'
|
320 |
+
assert repr(F(p)) == 'AnnihilateFermion(p)'
|
321 |
+
assert srepr(F(p)) == "AnnihilateFermion(Symbol('p'))"
|
322 |
+
assert latex(F(p)) == 'a_{p}'
|
323 |
+
|
324 |
+
|
325 |
+
def test_create_b():
|
326 |
+
i, j, n, m = symbols('i,j,n,m')
|
327 |
+
o = Bd(i)
|
328 |
+
assert isinstance(o, CreateBoson)
|
329 |
+
o = o.subs(i, j)
|
330 |
+
assert o.atoms(Symbol) == {j}
|
331 |
+
o = Bd(0)
|
332 |
+
assert o.apply_operator(BKet([n])) == sqrt(n + 1)*BKet([n + 1])
|
333 |
+
o = Bd(n)
|
334 |
+
assert o.apply_operator(BKet([n])) == o*BKet([n])
|
335 |
+
|
336 |
+
|
337 |
+
def test_annihilate_b():
|
338 |
+
i, j, n, m = symbols('i,j,n,m')
|
339 |
+
o = B(i)
|
340 |
+
assert isinstance(o, AnnihilateBoson)
|
341 |
+
o = o.subs(i, j)
|
342 |
+
assert o.atoms(Symbol) == {j}
|
343 |
+
o = B(0)
|
344 |
+
|
345 |
+
|
346 |
+
def test_wicks():
|
347 |
+
p, q, r, s = symbols('p,q,r,s', above_fermi=True)
|
348 |
+
|
349 |
+
# Testing for particles only
|
350 |
+
|
351 |
+
str = F(p)*Fd(q)
|
352 |
+
assert wicks(str) == NO(F(p)*Fd(q)) + KroneckerDelta(p, q)
|
353 |
+
str = Fd(p)*F(q)
|
354 |
+
assert wicks(str) == NO(Fd(p)*F(q))
|
355 |
+
|
356 |
+
str = F(p)*Fd(q)*F(r)*Fd(s)
|
357 |
+
nstr = wicks(str)
|
358 |
+
fasit = NO(
|
359 |
+
KroneckerDelta(p, q)*KroneckerDelta(r, s)
|
360 |
+
+ KroneckerDelta(p, q)*AnnihilateFermion(r)*CreateFermion(s)
|
361 |
+
+ KroneckerDelta(r, s)*AnnihilateFermion(p)*CreateFermion(q)
|
362 |
+
- KroneckerDelta(p, s)*AnnihilateFermion(r)*CreateFermion(q)
|
363 |
+
- AnnihilateFermion(p)*AnnihilateFermion(r)*CreateFermion(q)*CreateFermion(s))
|
364 |
+
assert nstr == fasit
|
365 |
+
|
366 |
+
assert (p*q*nstr).expand() == wicks(p*q*str)
|
367 |
+
assert (nstr*p*q*2).expand() == wicks(str*p*q*2)
|
368 |
+
|
369 |
+
# Testing CC equations particles and holes
|
370 |
+
i, j, k, l = symbols('i j k l', below_fermi=True, cls=Dummy)
|
371 |
+
a, b, c, d = symbols('a b c d', above_fermi=True, cls=Dummy)
|
372 |
+
p, q, r, s = symbols('p q r s', cls=Dummy)
|
373 |
+
|
374 |
+
assert (wicks(F(a)*NO(F(i)*F(j))*Fd(b)) ==
|
375 |
+
NO(F(a)*F(i)*F(j)*Fd(b)) +
|
376 |
+
KroneckerDelta(a, b)*NO(F(i)*F(j)))
|
377 |
+
assert (wicks(F(a)*NO(F(i)*F(j)*F(k))*Fd(b)) ==
|
378 |
+
NO(F(a)*F(i)*F(j)*F(k)*Fd(b)) -
|
379 |
+
KroneckerDelta(a, b)*NO(F(i)*F(j)*F(k)))
|
380 |
+
|
381 |
+
expr = wicks(Fd(i)*NO(Fd(j)*F(k))*F(l))
|
382 |
+
assert (expr ==
|
383 |
+
-KroneckerDelta(i, k)*NO(Fd(j)*F(l)) -
|
384 |
+
KroneckerDelta(j, l)*NO(Fd(i)*F(k)) -
|
385 |
+
KroneckerDelta(i, k)*KroneckerDelta(j, l) +
|
386 |
+
KroneckerDelta(i, l)*NO(Fd(j)*F(k)) +
|
387 |
+
NO(Fd(i)*Fd(j)*F(k)*F(l)))
|
388 |
+
expr = wicks(F(a)*NO(F(b)*Fd(c))*Fd(d))
|
389 |
+
assert (expr ==
|
390 |
+
-KroneckerDelta(a, c)*NO(F(b)*Fd(d)) -
|
391 |
+
KroneckerDelta(b, d)*NO(F(a)*Fd(c)) -
|
392 |
+
KroneckerDelta(a, c)*KroneckerDelta(b, d) +
|
393 |
+
KroneckerDelta(a, d)*NO(F(b)*Fd(c)) +
|
394 |
+
NO(F(a)*F(b)*Fd(c)*Fd(d)))
|
395 |
+
|
396 |
+
|
397 |
+
def test_NO():
|
398 |
+
i, j, k, l = symbols('i j k l', below_fermi=True)
|
399 |
+
a, b, c, d = symbols('a b c d', above_fermi=True)
|
400 |
+
p, q, r, s = symbols('p q r s', cls=Dummy)
|
401 |
+
|
402 |
+
assert (NO(Fd(p)*F(q) + Fd(a)*F(b)) ==
|
403 |
+
NO(Fd(p)*F(q)) + NO(Fd(a)*F(b)))
|
404 |
+
assert (NO(Fd(i)*NO(F(j)*Fd(a))) ==
|
405 |
+
NO(Fd(i)*F(j)*Fd(a)))
|
406 |
+
assert NO(1) == 1
|
407 |
+
assert NO(i) == i
|
408 |
+
assert (NO(Fd(a)*Fd(b)*(F(c) + F(d))) ==
|
409 |
+
NO(Fd(a)*Fd(b)*F(c)) +
|
410 |
+
NO(Fd(a)*Fd(b)*F(d)))
|
411 |
+
|
412 |
+
assert NO(Fd(a)*F(b))._remove_brackets() == Fd(a)*F(b)
|
413 |
+
assert NO(F(j)*Fd(i))._remove_brackets() == F(j)*Fd(i)
|
414 |
+
|
415 |
+
assert (NO(Fd(p)*F(q)).subs(Fd(p), Fd(a) + Fd(i)) ==
|
416 |
+
NO(Fd(a)*F(q)) + NO(Fd(i)*F(q)))
|
417 |
+
assert (NO(Fd(p)*F(q)).subs(F(q), F(a) + F(i)) ==
|
418 |
+
NO(Fd(p)*F(a)) + NO(Fd(p)*F(i)))
|
419 |
+
|
420 |
+
expr = NO(Fd(p)*F(q))._remove_brackets()
|
421 |
+
assert wicks(expr) == NO(expr)
|
422 |
+
|
423 |
+
assert NO(Fd(a)*F(b)) == - NO(F(b)*Fd(a))
|
424 |
+
|
425 |
+
no = NO(Fd(a)*F(i)*F(b)*Fd(j))
|
426 |
+
l1 = list(no.iter_q_creators())
|
427 |
+
assert l1 == [0, 1]
|
428 |
+
l2 = list(no.iter_q_annihilators())
|
429 |
+
assert l2 == [3, 2]
|
430 |
+
no = NO(Fd(a)*Fd(i))
|
431 |
+
assert no.has_q_creators == 1
|
432 |
+
assert no.has_q_annihilators == -1
|
433 |
+
assert str(no) == ':CreateFermion(a)*CreateFermion(i):'
|
434 |
+
assert repr(no) == 'NO(CreateFermion(a)*CreateFermion(i))'
|
435 |
+
assert latex(no) == r'\left\{{a^\dagger_{a}} {a^\dagger_{i}}\right\}'
|
436 |
+
raises(NotImplementedError, lambda: NO(Bd(p)*F(q)))
|
437 |
+
|
438 |
+
|
439 |
+
def test_sorting():
|
440 |
+
i, j = symbols('i,j', below_fermi=True)
|
441 |
+
a, b = symbols('a,b', above_fermi=True)
|
442 |
+
p, q = symbols('p,q')
|
443 |
+
|
444 |
+
# p, q
|
445 |
+
assert _sort_anticommuting_fermions([Fd(p), F(q)]) == ([Fd(p), F(q)], 0)
|
446 |
+
assert _sort_anticommuting_fermions([F(p), Fd(q)]) == ([Fd(q), F(p)], 1)
|
447 |
+
|
448 |
+
# i, p
|
449 |
+
assert _sort_anticommuting_fermions([F(p), Fd(i)]) == ([F(p), Fd(i)], 0)
|
450 |
+
assert _sort_anticommuting_fermions([Fd(i), F(p)]) == ([F(p), Fd(i)], 1)
|
451 |
+
assert _sort_anticommuting_fermions([Fd(p), Fd(i)]) == ([Fd(p), Fd(i)], 0)
|
452 |
+
assert _sort_anticommuting_fermions([Fd(i), Fd(p)]) == ([Fd(p), Fd(i)], 1)
|
453 |
+
assert _sort_anticommuting_fermions([F(p), F(i)]) == ([F(i), F(p)], 1)
|
454 |
+
assert _sort_anticommuting_fermions([F(i), F(p)]) == ([F(i), F(p)], 0)
|
455 |
+
assert _sort_anticommuting_fermions([Fd(p), F(i)]) == ([F(i), Fd(p)], 1)
|
456 |
+
assert _sort_anticommuting_fermions([F(i), Fd(p)]) == ([F(i), Fd(p)], 0)
|
457 |
+
|
458 |
+
# a, p
|
459 |
+
assert _sort_anticommuting_fermions([F(p), Fd(a)]) == ([Fd(a), F(p)], 1)
|
460 |
+
assert _sort_anticommuting_fermions([Fd(a), F(p)]) == ([Fd(a), F(p)], 0)
|
461 |
+
assert _sort_anticommuting_fermions([Fd(p), Fd(a)]) == ([Fd(a), Fd(p)], 1)
|
462 |
+
assert _sort_anticommuting_fermions([Fd(a), Fd(p)]) == ([Fd(a), Fd(p)], 0)
|
463 |
+
assert _sort_anticommuting_fermions([F(p), F(a)]) == ([F(p), F(a)], 0)
|
464 |
+
assert _sort_anticommuting_fermions([F(a), F(p)]) == ([F(p), F(a)], 1)
|
465 |
+
assert _sort_anticommuting_fermions([Fd(p), F(a)]) == ([Fd(p), F(a)], 0)
|
466 |
+
assert _sort_anticommuting_fermions([F(a), Fd(p)]) == ([Fd(p), F(a)], 1)
|
467 |
+
|
468 |
+
# i, a
|
469 |
+
assert _sort_anticommuting_fermions([F(i), Fd(j)]) == ([F(i), Fd(j)], 0)
|
470 |
+
assert _sort_anticommuting_fermions([Fd(j), F(i)]) == ([F(i), Fd(j)], 1)
|
471 |
+
assert _sort_anticommuting_fermions([Fd(a), Fd(i)]) == ([Fd(a), Fd(i)], 0)
|
472 |
+
assert _sort_anticommuting_fermions([Fd(i), Fd(a)]) == ([Fd(a), Fd(i)], 1)
|
473 |
+
assert _sort_anticommuting_fermions([F(a), F(i)]) == ([F(i), F(a)], 1)
|
474 |
+
assert _sort_anticommuting_fermions([F(i), F(a)]) == ([F(i), F(a)], 0)
|
475 |
+
|
476 |
+
|
477 |
+
def test_contraction():
|
478 |
+
i, j, k, l = symbols('i,j,k,l', below_fermi=True)
|
479 |
+
a, b, c, d = symbols('a,b,c,d', above_fermi=True)
|
480 |
+
p, q, r, s = symbols('p,q,r,s')
|
481 |
+
assert contraction(Fd(i), F(j)) == KroneckerDelta(i, j)
|
482 |
+
assert contraction(F(a), Fd(b)) == KroneckerDelta(a, b)
|
483 |
+
assert contraction(F(a), Fd(i)) == 0
|
484 |
+
assert contraction(Fd(a), F(i)) == 0
|
485 |
+
assert contraction(F(i), Fd(a)) == 0
|
486 |
+
assert contraction(Fd(i), F(a)) == 0
|
487 |
+
assert contraction(Fd(i), F(p)) == KroneckerDelta(i, p)
|
488 |
+
restr = evaluate_deltas(contraction(Fd(p), F(q)))
|
489 |
+
assert restr.is_only_below_fermi
|
490 |
+
restr = evaluate_deltas(contraction(F(p), Fd(q)))
|
491 |
+
assert restr.is_only_above_fermi
|
492 |
+
raises(ContractionAppliesOnlyToFermions, lambda: contraction(B(a), Fd(b)))
|
493 |
+
|
494 |
+
|
495 |
+
def test_evaluate_deltas():
|
496 |
+
i, j, k = symbols('i,j,k')
|
497 |
+
|
498 |
+
r = KroneckerDelta(i, j) * KroneckerDelta(j, k)
|
499 |
+
assert evaluate_deltas(r) == KroneckerDelta(i, k)
|
500 |
+
|
501 |
+
r = KroneckerDelta(i, 0) * KroneckerDelta(j, k)
|
502 |
+
assert evaluate_deltas(r) == KroneckerDelta(i, 0) * KroneckerDelta(j, k)
|
503 |
+
|
504 |
+
r = KroneckerDelta(1, j) * KroneckerDelta(j, k)
|
505 |
+
assert evaluate_deltas(r) == KroneckerDelta(1, k)
|
506 |
+
|
507 |
+
r = KroneckerDelta(j, 2) * KroneckerDelta(k, j)
|
508 |
+
assert evaluate_deltas(r) == KroneckerDelta(2, k)
|
509 |
+
|
510 |
+
r = KroneckerDelta(i, 0) * KroneckerDelta(i, j) * KroneckerDelta(j, 1)
|
511 |
+
assert evaluate_deltas(r) == 0
|
512 |
+
|
513 |
+
r = (KroneckerDelta(0, i) * KroneckerDelta(0, j)
|
514 |
+
* KroneckerDelta(1, j) * KroneckerDelta(1, j))
|
515 |
+
assert evaluate_deltas(r) == 0
|
516 |
+
|
517 |
+
|
518 |
+
def test_Tensors():
|
519 |
+
i, j, k, l = symbols('i j k l', below_fermi=True, cls=Dummy)
|
520 |
+
a, b, c, d = symbols('a b c d', above_fermi=True, cls=Dummy)
|
521 |
+
p, q, r, s = symbols('p q r s')
|
522 |
+
|
523 |
+
AT = AntiSymmetricTensor
|
524 |
+
assert AT('t', (a, b), (i, j)) == -AT('t', (b, a), (i, j))
|
525 |
+
assert AT('t', (a, b), (i, j)) == AT('t', (b, a), (j, i))
|
526 |
+
assert AT('t', (a, b), (i, j)) == -AT('t', (a, b), (j, i))
|
527 |
+
assert AT('t', (a, a), (i, j)) == 0
|
528 |
+
assert AT('t', (a, b), (i, i)) == 0
|
529 |
+
assert AT('t', (a, b, c), (i, j)) == -AT('t', (b, a, c), (i, j))
|
530 |
+
assert AT('t', (a, b, c), (i, j, k)) == AT('t', (b, a, c), (i, k, j))
|
531 |
+
|
532 |
+
tabij = AT('t', (a, b), (i, j))
|
533 |
+
assert tabij.has(a)
|
534 |
+
assert tabij.has(b)
|
535 |
+
assert tabij.has(i)
|
536 |
+
assert tabij.has(j)
|
537 |
+
assert tabij.subs(b, c) == AT('t', (a, c), (i, j))
|
538 |
+
assert (2*tabij).subs(i, c) == 2*AT('t', (a, b), (c, j))
|
539 |
+
assert tabij.symbol == Symbol('t')
|
540 |
+
assert latex(tabij) == '{t^{ab}_{ij}}'
|
541 |
+
assert str(tabij) == 't((_a, _b),(_i, _j))'
|
542 |
+
|
543 |
+
assert AT('t', (a, a), (i, j)).subs(a, b) == AT('t', (b, b), (i, j))
|
544 |
+
assert AT('t', (a, i), (a, j)).subs(a, b) == AT('t', (b, i), (b, j))
|
545 |
+
|
546 |
+
|
547 |
+
def test_fully_contracted():
|
548 |
+
i, j, k, l = symbols('i j k l', below_fermi=True)
|
549 |
+
a, b, c, d = symbols('a b c d', above_fermi=True)
|
550 |
+
p, q, r, s = symbols('p q r s', cls=Dummy)
|
551 |
+
|
552 |
+
Fock = (AntiSymmetricTensor('f', (p,), (q,))*
|
553 |
+
NO(Fd(p)*F(q)))
|
554 |
+
V = (AntiSymmetricTensor('v', (p, q), (r, s))*
|
555 |
+
NO(Fd(p)*Fd(q)*F(s)*F(r)))/4
|
556 |
+
|
557 |
+
Fai = wicks(NO(Fd(i)*F(a))*Fock,
|
558 |
+
keep_only_fully_contracted=True,
|
559 |
+
simplify_kronecker_deltas=True)
|
560 |
+
assert Fai == AntiSymmetricTensor('f', (a,), (i,))
|
561 |
+
Vabij = wicks(NO(Fd(i)*Fd(j)*F(b)*F(a))*V,
|
562 |
+
keep_only_fully_contracted=True,
|
563 |
+
simplify_kronecker_deltas=True)
|
564 |
+
assert Vabij == AntiSymmetricTensor('v', (a, b), (i, j))
|
565 |
+
|
566 |
+
|
567 |
+
def test_substitute_dummies_without_dummies():
|
568 |
+
i, j = symbols('i,j')
|
569 |
+
assert substitute_dummies(att(i, j) + 2) == att(i, j) + 2
|
570 |
+
assert substitute_dummies(att(i, j) + 1) == att(i, j) + 1
|
571 |
+
|
572 |
+
|
573 |
+
def test_substitute_dummies_NO_operator():
|
574 |
+
i, j = symbols('i j', cls=Dummy)
|
575 |
+
assert substitute_dummies(att(i, j)*NO(Fd(i)*F(j))
|
576 |
+
- att(j, i)*NO(Fd(j)*F(i))) == 0
|
577 |
+
|
578 |
+
|
579 |
+
def test_substitute_dummies_SQ_operator():
|
580 |
+
i, j = symbols('i j', cls=Dummy)
|
581 |
+
assert substitute_dummies(att(i, j)*Fd(i)*F(j)
|
582 |
+
- att(j, i)*Fd(j)*F(i)) == 0
|
583 |
+
|
584 |
+
|
585 |
+
def test_substitute_dummies_new_indices():
|
586 |
+
i, j = symbols('i j', below_fermi=True, cls=Dummy)
|
587 |
+
a, b = symbols('a b', above_fermi=True, cls=Dummy)
|
588 |
+
p, q = symbols('p q', cls=Dummy)
|
589 |
+
f = Function('f')
|
590 |
+
assert substitute_dummies(f(i, a, p) - f(j, b, q), new_indices=True) == 0
|
591 |
+
|
592 |
+
|
593 |
+
def test_substitute_dummies_substitution_order():
|
594 |
+
i, j, k, l = symbols('i j k l', below_fermi=True, cls=Dummy)
|
595 |
+
f = Function('f')
|
596 |
+
from sympy.utilities.iterables import variations
|
597 |
+
for permut in variations([i, j, k, l], 4):
|
598 |
+
assert substitute_dummies(f(*permut) - f(i, j, k, l)) == 0
|
599 |
+
|
600 |
+
|
601 |
+
def test_dummy_order_inner_outer_lines_VT1T1T1():
|
602 |
+
ii = symbols('i', below_fermi=True)
|
603 |
+
aa = symbols('a', above_fermi=True)
|
604 |
+
k, l = symbols('k l', below_fermi=True, cls=Dummy)
|
605 |
+
c, d = symbols('c d', above_fermi=True, cls=Dummy)
|
606 |
+
|
607 |
+
v = Function('v')
|
608 |
+
t = Function('t')
|
609 |
+
dums = _get_ordered_dummies
|
610 |
+
|
611 |
+
# Coupled-Cluster T1 terms with V*T1*T1*T1
|
612 |
+
# t^{a}_{k} t^{c}_{i} t^{d}_{l} v^{lk}_{dc}
|
613 |
+
exprs = [
|
614 |
+
# permut v and t <=> swapping internal lines, equivalent
|
615 |
+
# irrespective of symmetries in v
|
616 |
+
v(k, l, c, d)*t(c, ii)*t(d, l)*t(aa, k),
|
617 |
+
v(l, k, c, d)*t(c, ii)*t(d, k)*t(aa, l),
|
618 |
+
v(k, l, d, c)*t(d, ii)*t(c, l)*t(aa, k),
|
619 |
+
v(l, k, d, c)*t(d, ii)*t(c, k)*t(aa, l),
|
620 |
+
]
|
621 |
+
for permut in exprs[1:]:
|
622 |
+
assert dums(exprs[0]) != dums(permut)
|
623 |
+
assert substitute_dummies(exprs[0]) == substitute_dummies(permut)
|
624 |
+
|
625 |
+
|
626 |
+
def test_dummy_order_inner_outer_lines_VT1T1T1T1():
|
627 |
+
ii, jj = symbols('i j', below_fermi=True)
|
628 |
+
aa, bb = symbols('a b', above_fermi=True)
|
629 |
+
k, l = symbols('k l', below_fermi=True, cls=Dummy)
|
630 |
+
c, d = symbols('c d', above_fermi=True, cls=Dummy)
|
631 |
+
|
632 |
+
v = Function('v')
|
633 |
+
t = Function('t')
|
634 |
+
dums = _get_ordered_dummies
|
635 |
+
|
636 |
+
# Coupled-Cluster T2 terms with V*T1*T1*T1*T1
|
637 |
+
exprs = [
|
638 |
+
# permut t <=> swapping external lines, not equivalent
|
639 |
+
# except if v has certain symmetries.
|
640 |
+
v(k, l, c, d)*t(c, ii)*t(d, jj)*t(aa, k)*t(bb, l),
|
641 |
+
v(k, l, c, d)*t(c, jj)*t(d, ii)*t(aa, k)*t(bb, l),
|
642 |
+
v(k, l, c, d)*t(c, ii)*t(d, jj)*t(bb, k)*t(aa, l),
|
643 |
+
v(k, l, c, d)*t(c, jj)*t(d, ii)*t(bb, k)*t(aa, l),
|
644 |
+
]
|
645 |
+
for permut in exprs[1:]:
|
646 |
+
assert dums(exprs[0]) != dums(permut)
|
647 |
+
assert substitute_dummies(exprs[0]) != substitute_dummies(permut)
|
648 |
+
exprs = [
|
649 |
+
# permut v <=> swapping external lines, not equivalent
|
650 |
+
# except if v has certain symmetries.
|
651 |
+
#
|
652 |
+
# Note that in contrast to above, these permutations have identical
|
653 |
+
# dummy order. That is because the proximity to external indices
|
654 |
+
# has higher influence on the canonical dummy ordering than the
|
655 |
+
# position of a dummy on the factors. In fact, the terms here are
|
656 |
+
# similar in structure as the result of the dummy substitutions above.
|
657 |
+
v(k, l, c, d)*t(c, ii)*t(d, jj)*t(aa, k)*t(bb, l),
|
658 |
+
v(l, k, c, d)*t(c, ii)*t(d, jj)*t(aa, k)*t(bb, l),
|
659 |
+
v(k, l, d, c)*t(c, ii)*t(d, jj)*t(aa, k)*t(bb, l),
|
660 |
+
v(l, k, d, c)*t(c, ii)*t(d, jj)*t(aa, k)*t(bb, l),
|
661 |
+
]
|
662 |
+
for permut in exprs[1:]:
|
663 |
+
assert dums(exprs[0]) == dums(permut)
|
664 |
+
assert substitute_dummies(exprs[0]) != substitute_dummies(permut)
|
665 |
+
exprs = [
|
666 |
+
# permut t and v <=> swapping internal lines, equivalent.
|
667 |
+
# Canonical dummy order is different, and a consistent
|
668 |
+
# substitution reveals the equivalence.
|
669 |
+
v(k, l, c, d)*t(c, ii)*t(d, jj)*t(aa, k)*t(bb, l),
|
670 |
+
v(k, l, d, c)*t(c, jj)*t(d, ii)*t(aa, k)*t(bb, l),
|
671 |
+
v(l, k, c, d)*t(c, ii)*t(d, jj)*t(bb, k)*t(aa, l),
|
672 |
+
v(l, k, d, c)*t(c, jj)*t(d, ii)*t(bb, k)*t(aa, l),
|
673 |
+
]
|
674 |
+
for permut in exprs[1:]:
|
675 |
+
assert dums(exprs[0]) != dums(permut)
|
676 |
+
assert substitute_dummies(exprs[0]) == substitute_dummies(permut)
|
677 |
+
|
678 |
+
|
679 |
+
def test_get_subNO():
|
680 |
+
p, q, r = symbols('p,q,r')
|
681 |
+
assert NO(F(p)*F(q)*F(r)).get_subNO(1) == NO(F(p)*F(r))
|
682 |
+
assert NO(F(p)*F(q)*F(r)).get_subNO(0) == NO(F(q)*F(r))
|
683 |
+
assert NO(F(p)*F(q)*F(r)).get_subNO(2) == NO(F(p)*F(q))
|
684 |
+
|
685 |
+
|
686 |
+
def test_equivalent_internal_lines_VT1T1():
|
687 |
+
i, j, k, l = symbols('i j k l', below_fermi=True, cls=Dummy)
|
688 |
+
a, b, c, d = symbols('a b c d', above_fermi=True, cls=Dummy)
|
689 |
+
|
690 |
+
v = Function('v')
|
691 |
+
t = Function('t')
|
692 |
+
dums = _get_ordered_dummies
|
693 |
+
|
694 |
+
exprs = [ # permute v. Different dummy order. Not equivalent.
|
695 |
+
v(i, j, a, b)*t(a, i)*t(b, j),
|
696 |
+
v(j, i, a, b)*t(a, i)*t(b, j),
|
697 |
+
v(i, j, b, a)*t(a, i)*t(b, j),
|
698 |
+
]
|
699 |
+
for permut in exprs[1:]:
|
700 |
+
assert dums(exprs[0]) != dums(permut)
|
701 |
+
assert substitute_dummies(exprs[0]) != substitute_dummies(permut)
|
702 |
+
|
703 |
+
exprs = [ # permute v. Different dummy order. Equivalent
|
704 |
+
v(i, j, a, b)*t(a, i)*t(b, j),
|
705 |
+
v(j, i, b, a)*t(a, i)*t(b, j),
|
706 |
+
]
|
707 |
+
for permut in exprs[1:]:
|
708 |
+
assert dums(exprs[0]) != dums(permut)
|
709 |
+
assert substitute_dummies(exprs[0]) == substitute_dummies(permut)
|
710 |
+
|
711 |
+
exprs = [ # permute t. Same dummy order, not equivalent.
|
712 |
+
v(i, j, a, b)*t(a, i)*t(b, j),
|
713 |
+
v(i, j, a, b)*t(b, i)*t(a, j),
|
714 |
+
]
|
715 |
+
for permut in exprs[1:]:
|
716 |
+
assert dums(exprs[0]) == dums(permut)
|
717 |
+
assert substitute_dummies(exprs[0]) != substitute_dummies(permut)
|
718 |
+
|
719 |
+
exprs = [ # permute v and t. Different dummy order, equivalent
|
720 |
+
v(i, j, a, b)*t(a, i)*t(b, j),
|
721 |
+
v(j, i, a, b)*t(a, j)*t(b, i),
|
722 |
+
v(i, j, b, a)*t(b, i)*t(a, j),
|
723 |
+
v(j, i, b, a)*t(b, j)*t(a, i),
|
724 |
+
]
|
725 |
+
for permut in exprs[1:]:
|
726 |
+
assert dums(exprs[0]) != dums(permut)
|
727 |
+
assert substitute_dummies(exprs[0]) == substitute_dummies(permut)
|
728 |
+
|
729 |
+
|
730 |
+
def test_equivalent_internal_lines_VT2conjT2():
|
731 |
+
# this diagram requires special handling in TCE
|
732 |
+
i, j, k, l, m, n = symbols('i j k l m n', below_fermi=True, cls=Dummy)
|
733 |
+
a, b, c, d, e, f = symbols('a b c d e f', above_fermi=True, cls=Dummy)
|
734 |
+
p1, p2, p3, p4 = symbols('p1 p2 p3 p4', above_fermi=True, cls=Dummy)
|
735 |
+
h1, h2, h3, h4 = symbols('h1 h2 h3 h4', below_fermi=True, cls=Dummy)
|
736 |
+
|
737 |
+
from sympy.utilities.iterables import variations
|
738 |
+
|
739 |
+
v = Function('v')
|
740 |
+
t = Function('t')
|
741 |
+
dums = _get_ordered_dummies
|
742 |
+
|
743 |
+
# v(abcd)t(abij)t(ijcd)
|
744 |
+
template = v(p1, p2, p3, p4)*t(p1, p2, i, j)*t(i, j, p3, p4)
|
745 |
+
permutator = variations([a, b, c, d], 4)
|
746 |
+
base = template.subs(zip([p1, p2, p3, p4], next(permutator)))
|
747 |
+
for permut in permutator:
|
748 |
+
subslist = zip([p1, p2, p3, p4], permut)
|
749 |
+
expr = template.subs(subslist)
|
750 |
+
assert dums(base) != dums(expr)
|
751 |
+
assert substitute_dummies(expr) == substitute_dummies(base)
|
752 |
+
template = v(p1, p2, p3, p4)*t(p1, p2, j, i)*t(j, i, p3, p4)
|
753 |
+
permutator = variations([a, b, c, d], 4)
|
754 |
+
base = template.subs(zip([p1, p2, p3, p4], next(permutator)))
|
755 |
+
for permut in permutator:
|
756 |
+
subslist = zip([p1, p2, p3, p4], permut)
|
757 |
+
expr = template.subs(subslist)
|
758 |
+
assert dums(base) != dums(expr)
|
759 |
+
assert substitute_dummies(expr) == substitute_dummies(base)
|
760 |
+
|
761 |
+
# v(abcd)t(abij)t(jicd)
|
762 |
+
template = v(p1, p2, p3, p4)*t(p1, p2, i, j)*t(j, i, p3, p4)
|
763 |
+
permutator = variations([a, b, c, d], 4)
|
764 |
+
base = template.subs(zip([p1, p2, p3, p4], next(permutator)))
|
765 |
+
for permut in permutator:
|
766 |
+
subslist = zip([p1, p2, p3, p4], permut)
|
767 |
+
expr = template.subs(subslist)
|
768 |
+
assert dums(base) != dums(expr)
|
769 |
+
assert substitute_dummies(expr) == substitute_dummies(base)
|
770 |
+
template = v(p1, p2, p3, p4)*t(p1, p2, j, i)*t(i, j, p3, p4)
|
771 |
+
permutator = variations([a, b, c, d], 4)
|
772 |
+
base = template.subs(zip([p1, p2, p3, p4], next(permutator)))
|
773 |
+
for permut in permutator:
|
774 |
+
subslist = zip([p1, p2, p3, p4], permut)
|
775 |
+
expr = template.subs(subslist)
|
776 |
+
assert dums(base) != dums(expr)
|
777 |
+
assert substitute_dummies(expr) == substitute_dummies(base)
|
778 |
+
|
779 |
+
|
780 |
+
def test_equivalent_internal_lines_VT2conjT2_ambiguous_order():
|
781 |
+
# These diagrams invokes _determine_ambiguous() because the
|
782 |
+
# dummies can not be ordered unambiguously by the key alone
|
783 |
+
i, j, k, l, m, n = symbols('i j k l m n', below_fermi=True, cls=Dummy)
|
784 |
+
a, b, c, d, e, f = symbols('a b c d e f', above_fermi=True, cls=Dummy)
|
785 |
+
p1, p2, p3, p4 = symbols('p1 p2 p3 p4', above_fermi=True, cls=Dummy)
|
786 |
+
h1, h2, h3, h4 = symbols('h1 h2 h3 h4', below_fermi=True, cls=Dummy)
|
787 |
+
|
788 |
+
from sympy.utilities.iterables import variations
|
789 |
+
|
790 |
+
v = Function('v')
|
791 |
+
t = Function('t')
|
792 |
+
dums = _get_ordered_dummies
|
793 |
+
|
794 |
+
# v(abcd)t(abij)t(cdij)
|
795 |
+
template = v(p1, p2, p3, p4)*t(p1, p2, i, j)*t(p3, p4, i, j)
|
796 |
+
permutator = variations([a, b, c, d], 4)
|
797 |
+
base = template.subs(zip([p1, p2, p3, p4], next(permutator)))
|
798 |
+
for permut in permutator:
|
799 |
+
subslist = zip([p1, p2, p3, p4], permut)
|
800 |
+
expr = template.subs(subslist)
|
801 |
+
assert dums(base) != dums(expr)
|
802 |
+
assert substitute_dummies(expr) == substitute_dummies(base)
|
803 |
+
template = v(p1, p2, p3, p4)*t(p1, p2, j, i)*t(p3, p4, i, j)
|
804 |
+
permutator = variations([a, b, c, d], 4)
|
805 |
+
base = template.subs(zip([p1, p2, p3, p4], next(permutator)))
|
806 |
+
for permut in permutator:
|
807 |
+
subslist = zip([p1, p2, p3, p4], permut)
|
808 |
+
expr = template.subs(subslist)
|
809 |
+
assert dums(base) != dums(expr)
|
810 |
+
assert substitute_dummies(expr) == substitute_dummies(base)
|
811 |
+
|
812 |
+
|
813 |
+
def test_equivalent_internal_lines_VT2():
|
814 |
+
i, j, k, l = symbols('i j k l', below_fermi=True, cls=Dummy)
|
815 |
+
a, b, c, d = symbols('a b c d', above_fermi=True, cls=Dummy)
|
816 |
+
|
817 |
+
v = Function('v')
|
818 |
+
t = Function('t')
|
819 |
+
dums = _get_ordered_dummies
|
820 |
+
exprs = [
|
821 |
+
# permute v. Same dummy order, not equivalent.
|
822 |
+
#
|
823 |
+
# This test show that the dummy order may not be sensitive to all
|
824 |
+
# index permutations. The following expressions have identical
|
825 |
+
# structure as the resulting terms from of the dummy substitutions
|
826 |
+
# in the test above. Here, all expressions have the same dummy
|
827 |
+
# order, so they cannot be simplified by means of dummy
|
828 |
+
# substitution. In order to simplify further, it is necessary to
|
829 |
+
# exploit symmetries in the objects, for instance if t or v is
|
830 |
+
# antisymmetric.
|
831 |
+
v(i, j, a, b)*t(a, b, i, j),
|
832 |
+
v(j, i, a, b)*t(a, b, i, j),
|
833 |
+
v(i, j, b, a)*t(a, b, i, j),
|
834 |
+
v(j, i, b, a)*t(a, b, i, j),
|
835 |
+
]
|
836 |
+
for permut in exprs[1:]:
|
837 |
+
assert dums(exprs[0]) == dums(permut)
|
838 |
+
assert substitute_dummies(exprs[0]) != substitute_dummies(permut)
|
839 |
+
|
840 |
+
exprs = [
|
841 |
+
# permute t.
|
842 |
+
v(i, j, a, b)*t(a, b, i, j),
|
843 |
+
v(i, j, a, b)*t(b, a, i, j),
|
844 |
+
v(i, j, a, b)*t(a, b, j, i),
|
845 |
+
v(i, j, a, b)*t(b, a, j, i),
|
846 |
+
]
|
847 |
+
for permut in exprs[1:]:
|
848 |
+
assert dums(exprs[0]) != dums(permut)
|
849 |
+
assert substitute_dummies(exprs[0]) != substitute_dummies(permut)
|
850 |
+
|
851 |
+
exprs = [ # permute v and t. Relabelling of dummies should be equivalent.
|
852 |
+
v(i, j, a, b)*t(a, b, i, j),
|
853 |
+
v(j, i, a, b)*t(a, b, j, i),
|
854 |
+
v(i, j, b, a)*t(b, a, i, j),
|
855 |
+
v(j, i, b, a)*t(b, a, j, i),
|
856 |
+
]
|
857 |
+
for permut in exprs[1:]:
|
858 |
+
assert dums(exprs[0]) != dums(permut)
|
859 |
+
assert substitute_dummies(exprs[0]) == substitute_dummies(permut)
|
860 |
+
|
861 |
+
|
862 |
+
def test_internal_external_VT2T2():
|
863 |
+
ii, jj = symbols('i j', below_fermi=True)
|
864 |
+
aa, bb = symbols('a b', above_fermi=True)
|
865 |
+
k, l = symbols('k l', below_fermi=True, cls=Dummy)
|
866 |
+
c, d = symbols('c d', above_fermi=True, cls=Dummy)
|
867 |
+
|
868 |
+
v = Function('v')
|
869 |
+
t = Function('t')
|
870 |
+
dums = _get_ordered_dummies
|
871 |
+
|
872 |
+
exprs = [
|
873 |
+
v(k, l, c, d)*t(aa, c, ii, k)*t(bb, d, jj, l),
|
874 |
+
v(l, k, c, d)*t(aa, c, ii, l)*t(bb, d, jj, k),
|
875 |
+
v(k, l, d, c)*t(aa, d, ii, k)*t(bb, c, jj, l),
|
876 |
+
v(l, k, d, c)*t(aa, d, ii, l)*t(bb, c, jj, k),
|
877 |
+
]
|
878 |
+
for permut in exprs[1:]:
|
879 |
+
assert dums(exprs[0]) != dums(permut)
|
880 |
+
assert substitute_dummies(exprs[0]) == substitute_dummies(permut)
|
881 |
+
exprs = [
|
882 |
+
v(k, l, c, d)*t(aa, c, ii, k)*t(d, bb, jj, l),
|
883 |
+
v(l, k, c, d)*t(aa, c, ii, l)*t(d, bb, jj, k),
|
884 |
+
v(k, l, d, c)*t(aa, d, ii, k)*t(c, bb, jj, l),
|
885 |
+
v(l, k, d, c)*t(aa, d, ii, l)*t(c, bb, jj, k),
|
886 |
+
]
|
887 |
+
for permut in exprs[1:]:
|
888 |
+
assert dums(exprs[0]) != dums(permut)
|
889 |
+
assert substitute_dummies(exprs[0]) == substitute_dummies(permut)
|
890 |
+
exprs = [
|
891 |
+
v(k, l, c, d)*t(c, aa, ii, k)*t(bb, d, jj, l),
|
892 |
+
v(l, k, c, d)*t(c, aa, ii, l)*t(bb, d, jj, k),
|
893 |
+
v(k, l, d, c)*t(d, aa, ii, k)*t(bb, c, jj, l),
|
894 |
+
v(l, k, d, c)*t(d, aa, ii, l)*t(bb, c, jj, k),
|
895 |
+
]
|
896 |
+
for permut in exprs[1:]:
|
897 |
+
assert dums(exprs[0]) != dums(permut)
|
898 |
+
assert substitute_dummies(exprs[0]) == substitute_dummies(permut)
|
899 |
+
|
900 |
+
|
901 |
+
def test_internal_external_pqrs():
|
902 |
+
ii, jj = symbols('i j')
|
903 |
+
aa, bb = symbols('a b')
|
904 |
+
k, l = symbols('k l', cls=Dummy)
|
905 |
+
c, d = symbols('c d', cls=Dummy)
|
906 |
+
|
907 |
+
v = Function('v')
|
908 |
+
t = Function('t')
|
909 |
+
dums = _get_ordered_dummies
|
910 |
+
|
911 |
+
exprs = [
|
912 |
+
v(k, l, c, d)*t(aa, c, ii, k)*t(bb, d, jj, l),
|
913 |
+
v(l, k, c, d)*t(aa, c, ii, l)*t(bb, d, jj, k),
|
914 |
+
v(k, l, d, c)*t(aa, d, ii, k)*t(bb, c, jj, l),
|
915 |
+
v(l, k, d, c)*t(aa, d, ii, l)*t(bb, c, jj, k),
|
916 |
+
]
|
917 |
+
for permut in exprs[1:]:
|
918 |
+
assert dums(exprs[0]) != dums(permut)
|
919 |
+
assert substitute_dummies(exprs[0]) == substitute_dummies(permut)
|
920 |
+
|
921 |
+
|
922 |
+
def test_dummy_order_well_defined():
|
923 |
+
aa, bb = symbols('a b', above_fermi=True)
|
924 |
+
k, l, m = symbols('k l m', below_fermi=True, cls=Dummy)
|
925 |
+
c, d = symbols('c d', above_fermi=True, cls=Dummy)
|
926 |
+
p, q = symbols('p q', cls=Dummy)
|
927 |
+
|
928 |
+
A = Function('A')
|
929 |
+
B = Function('B')
|
930 |
+
C = Function('C')
|
931 |
+
dums = _get_ordered_dummies
|
932 |
+
|
933 |
+
# We go through all key components in the order of increasing priority,
|
934 |
+
# and consider only fully orderable expressions. Non-orderable expressions
|
935 |
+
# are tested elsewhere.
|
936 |
+
|
937 |
+
# pos in first factor determines sort order
|
938 |
+
assert dums(A(k, l)*B(l, k)) == [k, l]
|
939 |
+
assert dums(A(l, k)*B(l, k)) == [l, k]
|
940 |
+
assert dums(A(k, l)*B(k, l)) == [k, l]
|
941 |
+
assert dums(A(l, k)*B(k, l)) == [l, k]
|
942 |
+
|
943 |
+
# factors involving the index
|
944 |
+
assert dums(A(k, l)*B(l, m)*C(k, m)) == [l, k, m]
|
945 |
+
assert dums(A(k, l)*B(l, m)*C(m, k)) == [l, k, m]
|
946 |
+
assert dums(A(l, k)*B(l, m)*C(k, m)) == [l, k, m]
|
947 |
+
assert dums(A(l, k)*B(l, m)*C(m, k)) == [l, k, m]
|
948 |
+
assert dums(A(k, l)*B(m, l)*C(k, m)) == [l, k, m]
|
949 |
+
assert dums(A(k, l)*B(m, l)*C(m, k)) == [l, k, m]
|
950 |
+
assert dums(A(l, k)*B(m, l)*C(k, m)) == [l, k, m]
|
951 |
+
assert dums(A(l, k)*B(m, l)*C(m, k)) == [l, k, m]
|
952 |
+
|
953 |
+
# same, but with factor order determined by non-dummies
|
954 |
+
assert dums(A(k, aa, l)*A(l, bb, m)*A(bb, k, m)) == [l, k, m]
|
955 |
+
assert dums(A(k, aa, l)*A(l, bb, m)*A(bb, m, k)) == [l, k, m]
|
956 |
+
assert dums(A(k, aa, l)*A(m, bb, l)*A(bb, k, m)) == [l, k, m]
|
957 |
+
assert dums(A(k, aa, l)*A(m, bb, l)*A(bb, m, k)) == [l, k, m]
|
958 |
+
assert dums(A(l, aa, k)*A(l, bb, m)*A(bb, k, m)) == [l, k, m]
|
959 |
+
assert dums(A(l, aa, k)*A(l, bb, m)*A(bb, m, k)) == [l, k, m]
|
960 |
+
assert dums(A(l, aa, k)*A(m, bb, l)*A(bb, k, m)) == [l, k, m]
|
961 |
+
assert dums(A(l, aa, k)*A(m, bb, l)*A(bb, m, k)) == [l, k, m]
|
962 |
+
|
963 |
+
# index range
|
964 |
+
assert dums(A(p, c, k)*B(p, c, k)) == [k, c, p]
|
965 |
+
assert dums(A(p, k, c)*B(p, c, k)) == [k, c, p]
|
966 |
+
assert dums(A(c, k, p)*B(p, c, k)) == [k, c, p]
|
967 |
+
assert dums(A(c, p, k)*B(p, c, k)) == [k, c, p]
|
968 |
+
assert dums(A(k, c, p)*B(p, c, k)) == [k, c, p]
|
969 |
+
assert dums(A(k, p, c)*B(p, c, k)) == [k, c, p]
|
970 |
+
assert dums(B(p, c, k)*A(p, c, k)) == [k, c, p]
|
971 |
+
assert dums(B(p, k, c)*A(p, c, k)) == [k, c, p]
|
972 |
+
assert dums(B(c, k, p)*A(p, c, k)) == [k, c, p]
|
973 |
+
assert dums(B(c, p, k)*A(p, c, k)) == [k, c, p]
|
974 |
+
assert dums(B(k, c, p)*A(p, c, k)) == [k, c, p]
|
975 |
+
assert dums(B(k, p, c)*A(p, c, k)) == [k, c, p]
|
976 |
+
|
977 |
+
|
978 |
+
def test_dummy_order_ambiguous():
|
979 |
+
aa, bb = symbols('a b', above_fermi=True)
|
980 |
+
i, j, k, l, m = symbols('i j k l m', below_fermi=True, cls=Dummy)
|
981 |
+
a, b, c, d, e = symbols('a b c d e', above_fermi=True, cls=Dummy)
|
982 |
+
p, q = symbols('p q', cls=Dummy)
|
983 |
+
p1, p2, p3, p4 = symbols('p1 p2 p3 p4', above_fermi=True, cls=Dummy)
|
984 |
+
p5, p6, p7, p8 = symbols('p5 p6 p7 p8', above_fermi=True, cls=Dummy)
|
985 |
+
h1, h2, h3, h4 = symbols('h1 h2 h3 h4', below_fermi=True, cls=Dummy)
|
986 |
+
h5, h6, h7, h8 = symbols('h5 h6 h7 h8', below_fermi=True, cls=Dummy)
|
987 |
+
|
988 |
+
A = Function('A')
|
989 |
+
B = Function('B')
|
990 |
+
|
991 |
+
from sympy.utilities.iterables import variations
|
992 |
+
|
993 |
+
# A*A*A*A*B -- ordering of p5 and p4 is used to figure out the rest
|
994 |
+
template = A(p1, p2)*A(p4, p1)*A(p2, p3)*A(p3, p5)*B(p5, p4)
|
995 |
+
permutator = variations([a, b, c, d, e], 5)
|
996 |
+
base = template.subs(zip([p1, p2, p3, p4, p5], next(permutator)))
|
997 |
+
for permut in permutator:
|
998 |
+
subslist = zip([p1, p2, p3, p4, p5], permut)
|
999 |
+
expr = template.subs(subslist)
|
1000 |
+
assert substitute_dummies(expr) == substitute_dummies(base)
|
1001 |
+
|
1002 |
+
# A*A*A*A*A -- an arbitrary index is assigned and the rest are figured out
|
1003 |
+
template = A(p1, p2)*A(p4, p1)*A(p2, p3)*A(p3, p5)*A(p5, p4)
|
1004 |
+
permutator = variations([a, b, c, d, e], 5)
|
1005 |
+
base = template.subs(zip([p1, p2, p3, p4, p5], next(permutator)))
|
1006 |
+
for permut in permutator:
|
1007 |
+
subslist = zip([p1, p2, p3, p4, p5], permut)
|
1008 |
+
expr = template.subs(subslist)
|
1009 |
+
assert substitute_dummies(expr) == substitute_dummies(base)
|
1010 |
+
|
1011 |
+
# A*A*A -- ordering of p5 and p4 is used to figure out the rest
|
1012 |
+
template = A(p1, p2, p4, p1)*A(p2, p3, p3, p5)*A(p5, p4)
|
1013 |
+
permutator = variations([a, b, c, d, e], 5)
|
1014 |
+
base = template.subs(zip([p1, p2, p3, p4, p5], next(permutator)))
|
1015 |
+
for permut in permutator:
|
1016 |
+
subslist = zip([p1, p2, p3, p4, p5], permut)
|
1017 |
+
expr = template.subs(subslist)
|
1018 |
+
assert substitute_dummies(expr) == substitute_dummies(base)
|
1019 |
+
|
1020 |
+
|
1021 |
+
def atv(*args):
|
1022 |
+
return AntiSymmetricTensor('v', args[:2], args[2:] )
|
1023 |
+
|
1024 |
+
|
1025 |
+
def att(*args):
|
1026 |
+
if len(args) == 4:
|
1027 |
+
return AntiSymmetricTensor('t', args[:2], args[2:] )
|
1028 |
+
elif len(args) == 2:
|
1029 |
+
return AntiSymmetricTensor('t', (args[0],), (args[1],))
|
1030 |
+
|
1031 |
+
|
1032 |
+
def test_dummy_order_inner_outer_lines_VT1T1T1_AT():
|
1033 |
+
ii = symbols('i', below_fermi=True)
|
1034 |
+
aa = symbols('a', above_fermi=True)
|
1035 |
+
k, l = symbols('k l', below_fermi=True, cls=Dummy)
|
1036 |
+
c, d = symbols('c d', above_fermi=True, cls=Dummy)
|
1037 |
+
|
1038 |
+
# Coupled-Cluster T1 terms with V*T1*T1*T1
|
1039 |
+
# t^{a}_{k} t^{c}_{i} t^{d}_{l} v^{lk}_{dc}
|
1040 |
+
exprs = [
|
1041 |
+
# permut v and t <=> swapping internal lines, equivalent
|
1042 |
+
# irrespective of symmetries in v
|
1043 |
+
atv(k, l, c, d)*att(c, ii)*att(d, l)*att(aa, k),
|
1044 |
+
atv(l, k, c, d)*att(c, ii)*att(d, k)*att(aa, l),
|
1045 |
+
atv(k, l, d, c)*att(d, ii)*att(c, l)*att(aa, k),
|
1046 |
+
atv(l, k, d, c)*att(d, ii)*att(c, k)*att(aa, l),
|
1047 |
+
]
|
1048 |
+
for permut in exprs[1:]:
|
1049 |
+
assert substitute_dummies(exprs[0]) == substitute_dummies(permut)
|
1050 |
+
|
1051 |
+
|
1052 |
+
def test_dummy_order_inner_outer_lines_VT1T1T1T1_AT():
|
1053 |
+
ii, jj = symbols('i j', below_fermi=True)
|
1054 |
+
aa, bb = symbols('a b', above_fermi=True)
|
1055 |
+
k, l = symbols('k l', below_fermi=True, cls=Dummy)
|
1056 |
+
c, d = symbols('c d', above_fermi=True, cls=Dummy)
|
1057 |
+
|
1058 |
+
# Coupled-Cluster T2 terms with V*T1*T1*T1*T1
|
1059 |
+
# non-equivalent substitutions (change of sign)
|
1060 |
+
exprs = [
|
1061 |
+
# permut t <=> swapping external lines
|
1062 |
+
atv(k, l, c, d)*att(c, ii)*att(d, jj)*att(aa, k)*att(bb, l),
|
1063 |
+
atv(k, l, c, d)*att(c, jj)*att(d, ii)*att(aa, k)*att(bb, l),
|
1064 |
+
atv(k, l, c, d)*att(c, ii)*att(d, jj)*att(bb, k)*att(aa, l),
|
1065 |
+
]
|
1066 |
+
for permut in exprs[1:]:
|
1067 |
+
assert substitute_dummies(exprs[0]) == -substitute_dummies(permut)
|
1068 |
+
|
1069 |
+
# equivalent substitutions
|
1070 |
+
exprs = [
|
1071 |
+
atv(k, l, c, d)*att(c, ii)*att(d, jj)*att(aa, k)*att(bb, l),
|
1072 |
+
# permut t <=> swapping external lines
|
1073 |
+
atv(k, l, c, d)*att(c, jj)*att(d, ii)*att(bb, k)*att(aa, l),
|
1074 |
+
]
|
1075 |
+
for permut in exprs[1:]:
|
1076 |
+
assert substitute_dummies(exprs[0]) == substitute_dummies(permut)
|
1077 |
+
|
1078 |
+
|
1079 |
+
def test_equivalent_internal_lines_VT1T1_AT():
|
1080 |
+
i, j, k, l = symbols('i j k l', below_fermi=True, cls=Dummy)
|
1081 |
+
a, b, c, d = symbols('a b c d', above_fermi=True, cls=Dummy)
|
1082 |
+
|
1083 |
+
exprs = [ # permute v. Different dummy order. Not equivalent.
|
1084 |
+
atv(i, j, a, b)*att(a, i)*att(b, j),
|
1085 |
+
atv(j, i, a, b)*att(a, i)*att(b, j),
|
1086 |
+
atv(i, j, b, a)*att(a, i)*att(b, j),
|
1087 |
+
]
|
1088 |
+
for permut in exprs[1:]:
|
1089 |
+
assert substitute_dummies(exprs[0]) != substitute_dummies(permut)
|
1090 |
+
|
1091 |
+
exprs = [ # permute v. Different dummy order. Equivalent
|
1092 |
+
atv(i, j, a, b)*att(a, i)*att(b, j),
|
1093 |
+
atv(j, i, b, a)*att(a, i)*att(b, j),
|
1094 |
+
]
|
1095 |
+
for permut in exprs[1:]:
|
1096 |
+
assert substitute_dummies(exprs[0]) == substitute_dummies(permut)
|
1097 |
+
|
1098 |
+
exprs = [ # permute t. Same dummy order, not equivalent.
|
1099 |
+
atv(i, j, a, b)*att(a, i)*att(b, j),
|
1100 |
+
atv(i, j, a, b)*att(b, i)*att(a, j),
|
1101 |
+
]
|
1102 |
+
for permut in exprs[1:]:
|
1103 |
+
assert substitute_dummies(exprs[0]) != substitute_dummies(permut)
|
1104 |
+
|
1105 |
+
exprs = [ # permute v and t. Different dummy order, equivalent
|
1106 |
+
atv(i, j, a, b)*att(a, i)*att(b, j),
|
1107 |
+
atv(j, i, a, b)*att(a, j)*att(b, i),
|
1108 |
+
atv(i, j, b, a)*att(b, i)*att(a, j),
|
1109 |
+
atv(j, i, b, a)*att(b, j)*att(a, i),
|
1110 |
+
]
|
1111 |
+
for permut in exprs[1:]:
|
1112 |
+
assert substitute_dummies(exprs[0]) == substitute_dummies(permut)
|
1113 |
+
|
1114 |
+
|
1115 |
+
def test_equivalent_internal_lines_VT2conjT2_AT():
|
1116 |
+
# this diagram requires special handling in TCE
|
1117 |
+
i, j, k, l, m, n = symbols('i j k l m n', below_fermi=True, cls=Dummy)
|
1118 |
+
a, b, c, d, e, f = symbols('a b c d e f', above_fermi=True, cls=Dummy)
|
1119 |
+
p1, p2, p3, p4 = symbols('p1 p2 p3 p4', above_fermi=True, cls=Dummy)
|
1120 |
+
h1, h2, h3, h4 = symbols('h1 h2 h3 h4', below_fermi=True, cls=Dummy)
|
1121 |
+
|
1122 |
+
from sympy.utilities.iterables import variations
|
1123 |
+
|
1124 |
+
# atv(abcd)att(abij)att(ijcd)
|
1125 |
+
template = atv(p1, p2, p3, p4)*att(p1, p2, i, j)*att(i, j, p3, p4)
|
1126 |
+
permutator = variations([a, b, c, d], 4)
|
1127 |
+
base = template.subs(zip([p1, p2, p3, p4], next(permutator)))
|
1128 |
+
for permut in permutator:
|
1129 |
+
subslist = zip([p1, p2, p3, p4], permut)
|
1130 |
+
expr = template.subs(subslist)
|
1131 |
+
assert substitute_dummies(expr) == substitute_dummies(base)
|
1132 |
+
template = atv(p1, p2, p3, p4)*att(p1, p2, j, i)*att(j, i, p3, p4)
|
1133 |
+
permutator = variations([a, b, c, d], 4)
|
1134 |
+
base = template.subs(zip([p1, p2, p3, p4], next(permutator)))
|
1135 |
+
for permut in permutator:
|
1136 |
+
subslist = zip([p1, p2, p3, p4], permut)
|
1137 |
+
expr = template.subs(subslist)
|
1138 |
+
assert substitute_dummies(expr) == substitute_dummies(base)
|
1139 |
+
|
1140 |
+
# atv(abcd)att(abij)att(jicd)
|
1141 |
+
template = atv(p1, p2, p3, p4)*att(p1, p2, i, j)*att(j, i, p3, p4)
|
1142 |
+
permutator = variations([a, b, c, d], 4)
|
1143 |
+
base = template.subs(zip([p1, p2, p3, p4], next(permutator)))
|
1144 |
+
for permut in permutator:
|
1145 |
+
subslist = zip([p1, p2, p3, p4], permut)
|
1146 |
+
expr = template.subs(subslist)
|
1147 |
+
assert substitute_dummies(expr) == substitute_dummies(base)
|
1148 |
+
template = atv(p1, p2, p3, p4)*att(p1, p2, j, i)*att(i, j, p3, p4)
|
1149 |
+
permutator = variations([a, b, c, d], 4)
|
1150 |
+
base = template.subs(zip([p1, p2, p3, p4], next(permutator)))
|
1151 |
+
for permut in permutator:
|
1152 |
+
subslist = zip([p1, p2, p3, p4], permut)
|
1153 |
+
expr = template.subs(subslist)
|
1154 |
+
assert substitute_dummies(expr) == substitute_dummies(base)
|
1155 |
+
|
1156 |
+
|
1157 |
+
def test_equivalent_internal_lines_VT2conjT2_ambiguous_order_AT():
|
1158 |
+
# These diagrams invokes _determine_ambiguous() because the
|
1159 |
+
# dummies can not be ordered unambiguously by the key alone
|
1160 |
+
i, j, k, l, m, n = symbols('i j k l m n', below_fermi=True, cls=Dummy)
|
1161 |
+
a, b, c, d, e, f = symbols('a b c d e f', above_fermi=True, cls=Dummy)
|
1162 |
+
p1, p2, p3, p4 = symbols('p1 p2 p3 p4', above_fermi=True, cls=Dummy)
|
1163 |
+
h1, h2, h3, h4 = symbols('h1 h2 h3 h4', below_fermi=True, cls=Dummy)
|
1164 |
+
|
1165 |
+
from sympy.utilities.iterables import variations
|
1166 |
+
|
1167 |
+
# atv(abcd)att(abij)att(cdij)
|
1168 |
+
template = atv(p1, p2, p3, p4)*att(p1, p2, i, j)*att(p3, p4, i, j)
|
1169 |
+
permutator = variations([a, b, c, d], 4)
|
1170 |
+
base = template.subs(zip([p1, p2, p3, p4], next(permutator)))
|
1171 |
+
for permut in permutator:
|
1172 |
+
subslist = zip([p1, p2, p3, p4], permut)
|
1173 |
+
expr = template.subs(subslist)
|
1174 |
+
assert substitute_dummies(expr) == substitute_dummies(base)
|
1175 |
+
template = atv(p1, p2, p3, p4)*att(p1, p2, j, i)*att(p3, p4, i, j)
|
1176 |
+
permutator = variations([a, b, c, d], 4)
|
1177 |
+
base = template.subs(zip([p1, p2, p3, p4], next(permutator)))
|
1178 |
+
for permut in permutator:
|
1179 |
+
subslist = zip([p1, p2, p3, p4], permut)
|
1180 |
+
expr = template.subs(subslist)
|
1181 |
+
assert substitute_dummies(expr) == substitute_dummies(base)
|
1182 |
+
|
1183 |
+
|
1184 |
+
def test_equivalent_internal_lines_VT2_AT():
|
1185 |
+
i, j, k, l = symbols('i j k l', below_fermi=True, cls=Dummy)
|
1186 |
+
a, b, c, d = symbols('a b c d', above_fermi=True, cls=Dummy)
|
1187 |
+
|
1188 |
+
exprs = [
|
1189 |
+
# permute v. Same dummy order, not equivalent.
|
1190 |
+
atv(i, j, a, b)*att(a, b, i, j),
|
1191 |
+
atv(j, i, a, b)*att(a, b, i, j),
|
1192 |
+
atv(i, j, b, a)*att(a, b, i, j),
|
1193 |
+
]
|
1194 |
+
for permut in exprs[1:]:
|
1195 |
+
assert substitute_dummies(exprs[0]) != substitute_dummies(permut)
|
1196 |
+
|
1197 |
+
exprs = [
|
1198 |
+
# permute t.
|
1199 |
+
atv(i, j, a, b)*att(a, b, i, j),
|
1200 |
+
atv(i, j, a, b)*att(b, a, i, j),
|
1201 |
+
atv(i, j, a, b)*att(a, b, j, i),
|
1202 |
+
]
|
1203 |
+
for permut in exprs[1:]:
|
1204 |
+
assert substitute_dummies(exprs[0]) != substitute_dummies(permut)
|
1205 |
+
|
1206 |
+
exprs = [ # permute v and t. Relabelling of dummies should be equivalent.
|
1207 |
+
atv(i, j, a, b)*att(a, b, i, j),
|
1208 |
+
atv(j, i, a, b)*att(a, b, j, i),
|
1209 |
+
atv(i, j, b, a)*att(b, a, i, j),
|
1210 |
+
atv(j, i, b, a)*att(b, a, j, i),
|
1211 |
+
]
|
1212 |
+
for permut in exprs[1:]:
|
1213 |
+
assert substitute_dummies(exprs[0]) == substitute_dummies(permut)
|
1214 |
+
|
1215 |
+
|
1216 |
+
def test_internal_external_VT2T2_AT():
|
1217 |
+
ii, jj = symbols('i j', below_fermi=True)
|
1218 |
+
aa, bb = symbols('a b', above_fermi=True)
|
1219 |
+
k, l = symbols('k l', below_fermi=True, cls=Dummy)
|
1220 |
+
c, d = symbols('c d', above_fermi=True, cls=Dummy)
|
1221 |
+
|
1222 |
+
exprs = [
|
1223 |
+
atv(k, l, c, d)*att(aa, c, ii, k)*att(bb, d, jj, l),
|
1224 |
+
atv(l, k, c, d)*att(aa, c, ii, l)*att(bb, d, jj, k),
|
1225 |
+
atv(k, l, d, c)*att(aa, d, ii, k)*att(bb, c, jj, l),
|
1226 |
+
atv(l, k, d, c)*att(aa, d, ii, l)*att(bb, c, jj, k),
|
1227 |
+
]
|
1228 |
+
for permut in exprs[1:]:
|
1229 |
+
assert substitute_dummies(exprs[0]) == substitute_dummies(permut)
|
1230 |
+
exprs = [
|
1231 |
+
atv(k, l, c, d)*att(aa, c, ii, k)*att(d, bb, jj, l),
|
1232 |
+
atv(l, k, c, d)*att(aa, c, ii, l)*att(d, bb, jj, k),
|
1233 |
+
atv(k, l, d, c)*att(aa, d, ii, k)*att(c, bb, jj, l),
|
1234 |
+
atv(l, k, d, c)*att(aa, d, ii, l)*att(c, bb, jj, k),
|
1235 |
+
]
|
1236 |
+
for permut in exprs[1:]:
|
1237 |
+
assert substitute_dummies(exprs[0]) == substitute_dummies(permut)
|
1238 |
+
exprs = [
|
1239 |
+
atv(k, l, c, d)*att(c, aa, ii, k)*att(bb, d, jj, l),
|
1240 |
+
atv(l, k, c, d)*att(c, aa, ii, l)*att(bb, d, jj, k),
|
1241 |
+
atv(k, l, d, c)*att(d, aa, ii, k)*att(bb, c, jj, l),
|
1242 |
+
atv(l, k, d, c)*att(d, aa, ii, l)*att(bb, c, jj, k),
|
1243 |
+
]
|
1244 |
+
for permut in exprs[1:]:
|
1245 |
+
assert substitute_dummies(exprs[0]) == substitute_dummies(permut)
|
1246 |
+
|
1247 |
+
|
1248 |
+
def test_internal_external_pqrs_AT():
|
1249 |
+
ii, jj = symbols('i j')
|
1250 |
+
aa, bb = symbols('a b')
|
1251 |
+
k, l = symbols('k l', cls=Dummy)
|
1252 |
+
c, d = symbols('c d', cls=Dummy)
|
1253 |
+
|
1254 |
+
exprs = [
|
1255 |
+
atv(k, l, c, d)*att(aa, c, ii, k)*att(bb, d, jj, l),
|
1256 |
+
atv(l, k, c, d)*att(aa, c, ii, l)*att(bb, d, jj, k),
|
1257 |
+
atv(k, l, d, c)*att(aa, d, ii, k)*att(bb, c, jj, l),
|
1258 |
+
atv(l, k, d, c)*att(aa, d, ii, l)*att(bb, c, jj, k),
|
1259 |
+
]
|
1260 |
+
for permut in exprs[1:]:
|
1261 |
+
assert substitute_dummies(exprs[0]) == substitute_dummies(permut)
|
1262 |
+
|
1263 |
+
|
1264 |
+
def test_issue_19661():
|
1265 |
+
a = Symbol('0')
|
1266 |
+
assert latex(Commutator(Bd(a)**2, B(a))
|
1267 |
+
) == '- \\left[b_{0},{b^\\dagger_{0}}^{2}\\right]'
|
1268 |
+
|
1269 |
+
|
1270 |
+
def test_canonical_ordering_AntiSymmetricTensor():
|
1271 |
+
v = symbols("v")
|
1272 |
+
|
1273 |
+
c, d = symbols(('c','d'), above_fermi=True,
|
1274 |
+
cls=Dummy)
|
1275 |
+
k, l = symbols(('k','l'), below_fermi=True,
|
1276 |
+
cls=Dummy)
|
1277 |
+
|
1278 |
+
# formerly, the left gave either the left or the right
|
1279 |
+
assert AntiSymmetricTensor(v, (k, l), (d, c)
|
1280 |
+
) == -AntiSymmetricTensor(v, (l, k), (d, c))
|
llmeval-env/lib/python3.10/site-packages/sympy/physics/tests/test_sho.py
ADDED
@@ -0,0 +1,21 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
+
from sympy.core import symbols, Rational, Function, diff
|
2 |
+
from sympy.physics.sho import R_nl, E_nl
|
3 |
+
from sympy.simplify.simplify import simplify
|
4 |
+
|
5 |
+
|
6 |
+
def test_sho_R_nl():
|
7 |
+
omega, r = symbols('omega r')
|
8 |
+
l = symbols('l', integer=True)
|
9 |
+
u = Function('u')
|
10 |
+
|
11 |
+
# check that it obeys the Schrodinger equation
|
12 |
+
for n in range(5):
|
13 |
+
schreq = ( -diff(u(r), r, 2)/2 + ((l*(l + 1))/(2*r**2)
|
14 |
+
+ omega**2*r**2/2 - E_nl(n, l, omega))*u(r) )
|
15 |
+
result = schreq.subs(u(r), r*R_nl(n, l, omega/2, r))
|
16 |
+
assert simplify(result.doit()) == 0
|
17 |
+
|
18 |
+
|
19 |
+
def test_energy():
|
20 |
+
n, l, hw = symbols('n l hw')
|
21 |
+
assert simplify(E_nl(n, l, hw) - (2*n + l + Rational(3, 2))*hw) == 0
|