.TILMedia.BaseClasses.PartialGasFunctions.densityDerivativeWRTpressure_psxi .TILMedia.BaseClasses.PartialGasFunctions.densityDerivativeWRTpressure_psxipartial function densityDerivativeWRTpressure_psxi = TILMedia.BaseClasses.PartialGasFunctionPrototypes.densityDerivativeWRTpressure_psxi;