def test_average_rt():
# TODO: investigate why this does not work
# angles = Angles.from_random_data(size=(3, 1, 100))
# or
# angles = Angles(np.arange(300).reshape((3, 1, 100)))
angles = Angles(np.random.rand(3, 1, 100))
seq = "xyz"
rt = Rototrans.from_euler_angles(angles, seq)
rt_mean = Rototrans.from_averaged_rototrans(rt)
angles_mean = Angles.from_rototrans(rt_mean, seq).isel(time=0)
angles_mean_ref = Angles.from_rototrans(rt, seq).mean(dim="time")
np.testing.assert_array_almost_equal(angles_mean,
angles_mean_ref,
decimal=2)
def test_euler2rot_rot2euleur(seq, angles=ANGLES, epsilon=EPSILON):
if seq == "zyzz":
angles_to_test = angles[:3, ...]
else:
angles_to_test = angles[:len(seq), ...]
r = Rototrans.from_euler_angles(angles=angles_to_test, angle_sequence=seq)
a = Angles.from_rototrans(rt=r, angle_sequence=seq)
np.testing.assert_array_less((a - angles_to_test).meca.abs().sum(),
epsilon)
def test_average_rt():
seq = "xyz"
angles_size = (3, 1, 100)
ref_angles_from_rt_mean = [0.25265133, 0.57436872, 0.79133042]
restart_seed()
angles = Angles.from_random_data(size=angles_size)
# min-max normalization to keep the angles low
angles = angles.pipe(lambda x: (x - x.min()) / (x.max() - x.min()))
rt = Rototrans.from_euler_angles(angles, seq)
rt_mean = Rototrans.from_averaged_rototrans(rt)
angles_from_rt_mean = Angles.from_rototrans(rt_mean, seq)
np.testing.assert_almost_equal(angles_from_rt_mean.data.ravel(),
ref_angles_from_rt_mean,
decimal=4)
def rototrans_from_averaged_rototrans(
caller: Callable, rt: xr.DataArray
) -> xr.DataArray:
# arbitrary angle sequence
seq = "xyz"
target = rt.mean(dim="time").expand_dims("time", axis=-1)
angles = Angles(np.ndarray((3, 1, 1)))
def objective_function(x):
angles[:3, 0, 0] = x
rt = caller.from_euler_angles(angles, seq)
return np.ravel(rt.meca.rotation - target.meca.rotation)
initia_guess = Angles.from_rototrans(target, seq).squeeze()
angles[:3, 0, 0] = least_squares(objective_function, initia_guess).x
return caller.from_euler_angles(angles, seq, translations=target.meca.translation)