def METHOD_NAME(ctx, coeffs):
    """
    Evaluate equation (11) on p. 484.
    """
    ln_p = coeffs['c1'] + coeffs['c2']*ctx.mag + \
        coeffs['c3']*(CONSTS['ref_mag'] - ctx.mag)**3 + \
        coeffs['c4']*np.log(
            ctx.rrup + coeffs['c5']*np.exp(coeffs['c6']*ctx.mag))
    return ln_p