calculate bulk modulus, wrapper for cal_k_vinet
    cannot handle uncertainties

    :param p: pressure in GPa
    :param v0: unit-cell volume in A^3 at 1 bar
    :param k0: bulk modulus at reference conditions
    :param k0p: pressure derivative of bulk modulus at reference conditions
    :return: bulk modulus at high pressure in GPa

def vinet_k(p, v0, k0, k0p, numerical=False):
    """
    calculate bulk modulus, wrapper for cal_k_vinet
    cannot handle uncertainties

    :param p: pressure in GPa
    :param v0: unit-cell volume in A^3 at 1 bar
    :param k0: bulk modulus at reference conditions
    :param k0p: pressure derivative of bulk modulus at reference conditions
    :return: bulk modulus at high pressure in GPa
    """
    f_u = uct.wrap(cal_k_vinet)
    return f_u(p, [v0, k0, k0p])