Derivative of density wrt. pressure at constant specific entropy in liquid region for given pressure and specific entropy
function dd2ps_Ps input Units.SI.AbsolutePressure p "Pressure"; input Units.SI.SpecificEntropy s "Specific entropy"; output Units.SI.DerDensityByPressure ddps "Derivative of density wrt. pressure at constant specific entropy"; end dd2ps_Ps;