rotate

Specification

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

Purpose & Params

Given $p = \[0,r\]$ and a unit quaternion $q = \[cos(\theta),n \cdot sin(\theta)\]$ , then the rotation of p is given by

$p' = qpq*$

the it represents a rotation of $2 \theta$ radians around the axis n

Example

    r      = np.array([1,0,0])
    n      = np.array([0,1,0])
    radian = (0.5 * np.pi) / 2
    q      = np.array([np.cos(radian),n[0]*np.sin(radian),n[1]*np.sin(radian),n[2]*np.sin(radian)], dtype=np.float64)
    print(quat.rotate(q, r))

output:

   array([0.0,0.0,-1.0])