def rect_radius(ellipsoid):
    """
    Computes the Rectifying Radius of an Ellipsoid with specified Inverse Flattening
    (See Ref 2 Equation 3)
    :param ellipsoid: Ellipsoid Object
    :return: Ellipsoid Rectifying Radius
    """
    nval = (1 / float(ellipsoid.inversef)) / (2 - (1 / float(ellipsoid.inversef)))
    nval2 = nval ** 2
    return (ellipsoid.semimaj / (1 + nval) * ((nval2 *
                                              (nval2 *
                                               (nval2 *
                                                (25 * nval2 + 64)
                                                + 256)
                                               + 4096)
                                              + 16384)
                                              / 16384.))