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