Method and program for the numerical calculation of discrete stellar models with pressure depending on the density and spatial coordinate

A method for computation of discrete hydrostatic equilibrium stellar models is described for the case when the dependence of pressure on density and spatial coordinate is specified. The appropriate finite-difference equations are solved by fitting at an arbitrary intermediate interface of two successive inversely directed integrations, with one starting from stellar centre and the other from stellar surface. The effectiveness of the method is demonstrated by calculating the finite-difference polytropic stellar models. A brief description of the program realizing the algorithm proposed and proper operational instructions are presented as well