Bug in finite difference function in tests/python/utils.py

[edantec]

Bug description

The finite difference function in tests/python/utils.py does not integrate correctly the Jacobian transport on Lie manifold. The test of finite differences for MultibodyFreeFwdDynamics is also lacking in Python.

Expected behavior

Working unittest for MultibodyFreeFwdDynamics using the finite difference function in tests/python/utils.py.

Reproduction steps

Steps to reproduce the behavior:

1. Open unittest tests/python/test_continuous_dynamics.py

2. In function test_multibody_free(), add finite difference test for MultibodyFreeFwdDynamics, e.g.:

   Jx0 = data.Jx.copy()
   Ju0 = data.Ju.copy()
   Jxdiff, Judiff = finite_diff(ode, space, x0, u0, epsilon)
   
   assert np.linalg.norm(Jxdiff - Jx0) <= epsilon
   assert np.linalg.norm(Judiff - Ju0) <= epsilon

3. Run unittest
4. See error

[ManifoldFR]

Is this still a problem ? Or did #128 fix it