def METHOD_NAME(self, x, y, logM, concentration, e1, e2, center_x=0, center_y=0):
    """Return df/dx and df/dy of the function (integral of NFW).
    :param x: angular position
    :param y: angular position
    :param Rs: angular turn over point
    :param alpha_Rs: deflection at Rs
    :param e1: eccentricity component in x-direction
    :param e2: eccentricity component in y-direction
    :param center_x: center of halo
    :param center_y: center of halo
    :return:
    """
    Rs, alpha_Rs = self._m_c2deflections(logM, concentration)
    return self._nfw.METHOD_NAME(x, y, Rs, alpha_Rs, e1, e2, center_x, center_y)