c     Copyright (C) 2008-2014 Vincent Eymet
c
c     KDISTRIBUTION is free software; you can redistribute it and/or modify
c     it under the terms of the GNU General Public License as published by
c     the Free Software Foundation; either version 3, or (at your option)
c     any later version.

c     KDISTRIBUTION is distributed in the hope that it will be useful,
c     but WITHOUT ANY WARRANTY; without even the implied warranty of
c     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
c     GNU General Public License for more details.

c     You should have received a copy of the GNU General Public License
c     along with KDISTRIBUTION; if not, see <http://www.gnu.org/licenses/>
c
      subroutine calc_rho(mfile,tfile,i,rho)
      implicit none
      include 'max.inc'
c
c     Purpose: to compute the volumic mass (rho) of the gaseous mixture
c     on Venus, at interface index 'i'
c     
      integer strlen
      integer m,i
      double precision alt(1:Nmax)
      double precision pres(1:Nmax)
      double precision temp(1:Nmax)
      double precision Tsol
      double precision Tesp
      double precision Rgp,rho,Mass
      character*(Nchar_mx) mfile,tfile
c     label
      character*(Nchar_mx) label
      label='subroutine calc_rho'

      call read_model(m,alt,pres,temp,Tsol,Tesp)
      Rgp=1.0D+0*22.4D-3/(1.0D+0*273.15D+0) ! atm.m³/(mol.K)
      Mass=0.965D+0*44.0D+0+0.035D+0*28.0D+0 ! g/mol
      rho=Mass*1.0D-3*pres(i)/(Rgp*temp(i)) ! kg/m³
c     Debug
c      write(*,*) 'rho=',rho
c      write(*,*) 'Mass=',Mass
c      write(*,*) 'pres(',i,')=',pres(i)
c      write(*,*) 'Rgp=',Rgp
c      write(*,*) 'temp(',i,')=',temp(i)
c     Debug

      return
      end