Tracking down a bug in the PyDy code gen.

eom_formulation.py

import sympy as sm
import numpy as np
from pydy.models import n_link_pendulum_on_cart
from pydy.codegen.ode_function_generators import generate_ode_function

sys = n_link_pendulum_on_cart(10, True, True)

x = np.random.random(len(sys.coordinates) + len(sys.speeds))
t = 0.0
r = np.random.random(len(sys.specifieds_symbols))
p = np.random.random(len(sys.constants_symbols))

k_d_dict = sys.eom_method.kindiffdict()
coord_derivs = sm.Matrix([k_d_dict[q.diff()] for q in sys.eom_method.q[:]])

rhs = generate_ode_function(sys.eom_method.forcing,
                            sys.coordinates,
                            sys.speeds,
                            sys.constants_symbols,             
                            mass_matrix=sys.eom_method.mass_matrix,
                            coordinate_derivatives=coord_derivs, 
                            specifieds=sys.specifieds_symbols,
                            constants_arg_type='array',
                            specifieds_arg_type='array',
                            generator='cython')

xd = rhs(x, t, r, p)
print(xd)

rhs = generate_ode_function(sys.eom_method.forcing_full,
                            sys.coordinates,
                            sys.speeds,
                            sys.constants_symbols,
                            mass_matrix=sys.eom_method.mass_matrix_full,
                            specifieds=sys.specifieds_symbols,
                            constants_arg_type='array',
                            specifieds_arg_type='array',
                            generator='cython')
xd = rhs(x, t, r, p)
print(xd)