calculate static pressure at 300 K.

        :param v: unit-cell volume in A^3
        :return: static pressure at t_ref (=300 K) in GPa

def _hugoniot_p(self, v):
        """
        calculate static pressure at 300 K.

        :param v: unit-cell volume in A^3
        :return: static pressure at t_ref (=300 K) in GPa
        """
        rho = self._get_rho(v)
        params = self._set_params(self.params_hugoniot)
        if self.nonlinear:
            return hugoniot_p_nlin(rho, *params)
        else:
            return hugoniot_p(rho, *params)