density derivative by pressure
function ddph_props extends Modelica.Icons.Function; input Units.SI.Pressure p "pressure"; input Units.SI.SpecificEnthalpy h "specific enthalpy"; input ThermoSysPro.Properties.WaterSteam.Common.IF97BaseTwoPhase aux "auxiliary record"; output Units.SI.DerDensityByPressure ddph "density derivative by pressure"; end ddph_props;