def asymptotic_relation_radial(enn,numax,param):
    """
    Compute the asymptotic frequency for a radial mode.

    Parameters
    ----------
    enn : int
        The radial order of the mode.
    numax : float
        The frequency of maximum oscillation power
    param : array_like 
        Collection of the asypmtotic parameters in the order `[dnu, epsilon, 
        alpha]`.

    Returns
    -------
    freq_asymp : float
        The radial asymptotic frequency of given radial order `enn`.
    """
    freq_asymp = param[0]*(enn + param[1] + param[2]/2.*(enn - numax/param[0])^2)
    return freq_asymp