in safety_gym/envs/engine.py [0:0]
def quat2mat(quat):
''' Convert Quaternion to a 3x3 Rotation Matrix using mujoco '''
q = np.array(quat, dtype='float64')
m = np.zeros(9, dtype='float64')
mujoco_py.functions.mju_quat2Mat(m, q)
return m.reshape((3,3))