rot_deriv

rot_deriv(angle, axis, dAngle, dAxis): 

Gives a rotational derivative w/r/t some unspecified coordinate (you have to supply the chain rule terms)

angle: float

angle for rotation
axis: np.ndarray

axis for rotation
dAngle: float

chain rule angle deriv.
dAxis: np.ndarray

chain rule axis deriv.
:returns: np.ndarray

derivatives of the rotation matrices with respect to both the angle and the axis