function rho_ph_der extends Modelica.Icons.Function; input AbsolutePressure p "Pressure"; input SpecificEnthalpy h "Specific enthalpy"; input Common.InverseDerivatives_rhoT derivs "Record for derivatives"; input Real p_der "Derivative of pressure"; input Real h_der "Derivative of specific enthalpy"; output Real d_der "Derivative of density"; end rho_ph_der;