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from sympy.external import import_module |
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from sympy.utilities.decorator import doctest_depends_on |
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@doctest_depends_on(modules=('antlr4',)) |
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def parse_autolev(autolev_code, include_numeric=False): |
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"""Parses Autolev code (version 4.1) to SymPy code. |
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Parameters |
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========= |
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autolev_code : Can be an str or any object with a readlines() method (such as a file handle or StringIO). |
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include_numeric : boolean, optional |
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If True NumPy, PyDy, or other numeric code is included for numeric evaluation lines in the Autolev code. |
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Returns |
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======= |
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sympy_code : str |
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Equivalent SymPy and/or numpy/pydy code as the input code. |
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Example (Double Pendulum) |
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========================= |
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>>> my_al_text = ("MOTIONVARIABLES' Q{2}', U{2}'", |
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... "CONSTANTS L,M,G", |
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... "NEWTONIAN N", |
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... "FRAMES A,B", |
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... "SIMPROT(N, A, 3, Q1)", |
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... "SIMPROT(N, B, 3, Q2)", |
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... "W_A_N>=U1*N3>", |
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... "W_B_N>=U2*N3>", |
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... "POINT O", |
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... "PARTICLES P,R", |
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... "P_O_P> = L*A1>", |
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... "P_P_R> = L*B1>", |
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... "V_O_N> = 0>", |
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... "V2PTS(N, A, O, P)", |
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... "V2PTS(N, B, P, R)", |
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... "MASS P=M, R=M", |
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... "Q1' = U1", |
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... "Q2' = U2", |
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... "GRAVITY(G*N1>)", |
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... "ZERO = FR() + FRSTAR()", |
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... "KANE()", |
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... "INPUT M=1,G=9.81,L=1", |
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... "INPUT Q1=.1,Q2=.2,U1=0,U2=0", |
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... "INPUT TFINAL=10, INTEGSTP=.01", |
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... "CODE DYNAMICS() some_filename.c") |
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>>> my_al_text = '\\n'.join(my_al_text) |
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>>> from sympy.parsing.autolev import parse_autolev |
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>>> print(parse_autolev(my_al_text, include_numeric=True)) |
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import sympy.physics.mechanics as _me |
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import sympy as _sm |
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import math as m |
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import numpy as _np |
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<BLANKLINE> |
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q1, q2, u1, u2 = _me.dynamicsymbols('q1 q2 u1 u2') |
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q1_d, q2_d, u1_d, u2_d = _me.dynamicsymbols('q1_ q2_ u1_ u2_', 1) |
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l, m, g = _sm.symbols('l m g', real=True) |
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frame_n = _me.ReferenceFrame('n') |
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frame_a = _me.ReferenceFrame('a') |
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frame_b = _me.ReferenceFrame('b') |
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frame_a.orient(frame_n, 'Axis', [q1, frame_n.z]) |
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frame_b.orient(frame_n, 'Axis', [q2, frame_n.z]) |
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frame_a.set_ang_vel(frame_n, u1*frame_n.z) |
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frame_b.set_ang_vel(frame_n, u2*frame_n.z) |
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point_o = _me.Point('o') |
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particle_p = _me.Particle('p', _me.Point('p_pt'), _sm.Symbol('m')) |
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particle_r = _me.Particle('r', _me.Point('r_pt'), _sm.Symbol('m')) |
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particle_p.point.set_pos(point_o, l*frame_a.x) |
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particle_r.point.set_pos(particle_p.point, l*frame_b.x) |
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point_o.set_vel(frame_n, 0) |
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particle_p.point.v2pt_theory(point_o,frame_n,frame_a) |
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particle_r.point.v2pt_theory(particle_p.point,frame_n,frame_b) |
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particle_p.mass = m |
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particle_r.mass = m |
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force_p = particle_p.mass*(g*frame_n.x) |
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force_r = particle_r.mass*(g*frame_n.x) |
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kd_eqs = [q1_d - u1, q2_d - u2] |
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forceList = [(particle_p.point,particle_p.mass*(g*frame_n.x)), (particle_r.point,particle_r.mass*(g*frame_n.x))] |
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kane = _me.KanesMethod(frame_n, q_ind=[q1,q2], u_ind=[u1, u2], kd_eqs = kd_eqs) |
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fr, frstar = kane.kanes_equations([particle_p, particle_r], forceList) |
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zero = fr+frstar |
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from pydy.system import System |
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sys = System(kane, constants = {l:1, m:1, g:9.81}, |
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specifieds={}, |
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initial_conditions={q1:.1, q2:.2, u1:0, u2:0}, |
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times = _np.linspace(0.0, 10, 10/.01)) |
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<BLANKLINE> |
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y=sys.integrate() |
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<BLANKLINE> |
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""" |
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_autolev = import_module( |
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'sympy.parsing.autolev._parse_autolev_antlr', |
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import_kwargs={'fromlist': ['X']}) |
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if _autolev is not None: |
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return _autolev.parse_autolev(autolev_code, include_numeric) |
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