function der_isothermalCompressibility_pTxi extends TILMedia.BaseClasses.PartialGasObjectFunction; input SI.AbsolutePressure p "Pressure"; input SI.Temperature T "Temperature"; input SI.MassFraction[:] xi "Mass fractions of the first nc-1 components"; input TILMedia.Internals.TILMediaExternalObject gasPointer; input Real der_p "Pressure"; input Real der_T "Temperature"; input Real[:] der_xi "Mass fraction"; output Real der_kappa "Isothermal compressibility"; end der_isothermalCompressibility_pTxi;