quaternion.py 文件源码

def from_angle_axis(cls, theta, axis):
        """ Construct Quaternion from axis-angle representation """
        x, y, z = axis
        norm = math.sqrt(x*x + y*y + z*z)
        if 0 == norm:
            return cls([0, 0, 0, 1])
        t = math.sin(theta/2) / norm;
        return cls([x*t, y*t, z*t, math.cos(theta/2)])

    # Properties