skrobot.coordinates.math.quaternion_norm

skrobot.coordinates.math.quaternion_norm(q)

Return the norm of quaternion.

Parameters:

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

Returns:

norm_q – quaternion norm of q

Return type:

float

Examples

>>> from skrobot.coordinates.math import quaternion_norm
>>> q = [1, 1, 1, 1]
>>> quaternion_norm(q)
2.0
>>> q = [0, 0.7071067811865476, 0, 0.7071067811865476]
>>> quaternion_norm(q)
1.0