Derivative of density wrt. specific entropy at constant pressure in liquid region for given pressure and specific entropy
function dd1sp_Ps input Units.SI.AbsolutePressure p "Pressure"; input Units.SI.SpecificEntropy s "Specific entropy"; output ThermoSysPro.Units.xSI.DerDensityByEntropy ddsp "Derivative of density wrt. specific enthalpy at constant pressure"; end dd1sp_Ps;