skrobot.coordinates.math.quaternion_distance

skrobot.coordinates.math.quaternion_distance(q1, q2, absolute=False)

Return the distance of quaternion.

Parameters:

• q1 (list or numpy.ndarray) –

• q2 (list or numpy.ndarray) – [w, x, y, z] order

• absolute (bool) – if True, return distance accounting for the sign ambiguity.

Returns:

diff_theta – distance of q1 and q2 in radian.

Return type:

float

Examples

>>> from skrobot.coordinates.math import quaternion_distance
>>> quaternion_distance([1, 0, 0, 0], [1, 0, 0, 0])
0.0
>>> quaternion_distance([1, 0, 0, 0], [0, 1, 0, 0])
3.141592653589793
>>> distance = quaternion_distance(
        [1, 0, 0, 0],
        [0.8660254, 0, 0.5, 0])
>>> np.rad2deg(distance)
60.00000021683236