def METHOD_NAME(phi, q):
    """Transforms orientation angle and axis ratio into complex ellipticity moduli e1,
    e2.
    :param phi: angle of orientation (in radian)
    :param q: axis ratio minor axis / major axis
    :return: eccentricities e1 and e2 in complex ellipticity moduli
    """
    e1 = (1.0 - q) / (1.0 + q) * np.cos(2 * phi)
    e2 = (1.0 - q) / (1.0 + q) * np.sin(2 * phi)
    return e1, e2