Derivative function of rho_ph
function rho_ph_der extends Modelica.Icons.Function; input Modelica.Units.SI.Pressure p "pressure"; input Modelica.Units.SI.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;