derivative function for pure components
function der_temperature_phxi extends TILMedia.BaseClasses.PartialGasObjectFunction; input SI.AbsolutePressure p "Pressure"; input SI.SpecificEnthalpy h "Specific enthalpy"; input SI.MassFraction xi[:] "Mass fraction"; input TILMedia.Internals.TILMediaExternalObject gasPointer; input Real der_p "Pressure"; input Real der_h "Specific enthalpy"; input Real der_xi[:] "Mass fraction"; output Real der_T "Temperature"; end der_temperature_phxi;