Method PIP

include/CoolProp/AbstractState.h:1303–1305

Return the phase identification parameter (PIP) of G. Venkatarathnam and L.R. Oellrich, "Identification of the phase of a fluid using partial derivatives of pressure, volume, and temperature without reference to saturation properties: Applications in phase equilibria calculations"

    double fundamental_derivative_of_gas_dynamics();
    /// Return the phase identification parameter (PIP) of G. Venkatarathnam and L.R. Oellrich, "Identification of the phase of a fluid using partial derivatives of pressure, volume, and temperature without reference to saturation properties: Applications in phase equilibria calculations"
    double PIP() {
        return calc_PIP();
    };

    /// Calculate the "true" critical point for pure fluids where dpdrho|T and d2p/drho2|T are equal to zero
    void true_critical_point(double& T, double& rho) {