from_matrix

Specification

Location	Author	Maintained by
isl/math/quaternion.py	Kenny Erleben	DIKU

Purpose & Params

Converts an euler rotation matrix to a quaternion.

Example

    import numpy as np
    # Cosider the case where we want to convert a euler roation matrix, that
    # rotates 90 degrees on the x-axis
    radian    = (0.5*np.pi)/2
    M  = np.array([
        [1,                               0,                                 0],
        [0,       (1-2*(np.sin(radian)**2)),  -2*np.cos(radian)*np.sin(radian)],
        [0, 2*np.cos(radian)*np.sin(radian), 1-2*(np.sin(radian)**2)          ]
    ])
    print(quat.from_matrix(M))

output:

   array([    0.70710678, 0.70710678, 0.        , 0.        ])