skrobot.coordinates.math.rodrigues¶

skrobot.coordinates.math.rodrigues(axis, theta=None)[source]¶

Rodrigues formula.

See: Rodrigues’ rotation formula - Wikipedia.

See: Axis-angle representation - Wikipedia.

Parameters:

axis (numpy.ndarray or list) – [x, y, z] vector. You can give axis-angle representation to axis if theta is None.
theta (float or None (optional)) – radian. If None is given, calculate theta from axis.

Returns:

mat – 3x3 rotation matrix

Return type:

numpy.ndarray

Examples

>>> import numpy
>>> from skrobot.coordinates.math import rodrigues
>>> rodrigues([1, 0, 0], 0)
array([[1., 0., 0.],
       [0., 1., 0.],
       [0., 0., 1.]])
>>> rodrigues([1, 1, 1], numpy.pi)
array([[-0.33333333,  0.66666667,  0.66666667],
       [ 0.66666667, -0.33333333,  0.66666667],
       [ 0.66666667,  0.66666667, -0.33333333]])