A simple function that implements rotation by Euler angles.

euler_rot.py

import numpy as np
def euler_rot(XYZ,phi,theta,psi):
    '''Returns the points XYZ rotated by the given euler angles'''


    ERot = np.array([[np.cos(theta)*np.cos(psi), 
                      -np.cos(phi)*np.sin(psi) + np.sin(phi)*np.sin(theta)*np.cos(psi), 
                      np.sin(phi)*np.sin(psi) + np.cos(phi)*np.sin(theta)*np.cos(psi)],
                     [np.cos(theta)*np.sin(psi), 
                      np.cos(phi)*np.cos(psi) + np.sin(phi)*np.sin(theta)*np.sin(psi),
                      -np.sin(phi)*np.cos(psi) + np.cos(phi)*np.sin(theta)*np.sin(psi)],
                     [-np.sin(theta),
                      np.sin(phi)*np.cos(theta),
                      np.cos(phi)*np.cos(theta)]])

    return ERot.dot(XYZ)