def modified_T(t, delta, opts):
    """
    Computes the modified nonlinear strength for use with Chromaticity correction.

    See Webb et al. "Chromatic and Dispersive Effects in Nonlinear Integrable Optics"
    for a discussion of the requirements for the transformation of nonlinear strength parameter
    t to be applied in the calculation of the adjusted invariant.

    Arguments:
        t (float): The strength parameter for the nonlinear magnet
        delta (float): The relative momentum deviation of the particle.
        opts (options.Options): A Synergia options instance specifying the needed phase advance quanties

    Returns:
        t/correction (float): A corrected effective strength for the nonlinear magnet

    """

    mu0 = opts.full_tune
    nu0 = opts.tune
    Ch = opts.Ch
    correction = 1. - (mu0*delta*Ch/nu0)

    return t/correction