c  Mahc_Init_Data: Various Initial Data Routines for Mahc_Evolve
c  Copyright (C) 2001 Mark Miller

/*@@
  @file      shocktube.F
  @date      December 1999
  @author    Mark Miller
  @desc
     Various shocktube configurations for MAHC.
  @enddesc
@@*/

#include "cctk.h"
#include "cctk_Parameters.h"
#include "cctk_Arguments.h"

/*@@
  @routine    shocktube
  @date       December 1999
  @author     Mark Miller
  @desc
     Various shocktube configurations for MAHC.
  @enddesc
  @calls
  @calledby
  @history
  @endhistory
@@*/


      subroutine shocktube(CCTK_FARGUMENTS)
      implicit  none
      DECLARE_CCTK_FARGUMENTS
      DECLARE_CCTK_PARAMETERS
      INTEGER CCTK_Equals

c     Local Vars
      integer didit,i,j,k,nx,ny,nz

      nx = cctk_lsh(1)
      ny = cctk_lsh(2)
      nz = cctk_lsh(3)
      didit = 0

      if (CCTK_Equals(shocktube_type,'diagshock') == 1) then
         didit = 1
         do i=1,nx
         do j=1,ny
         do k=1,nz
            if(x(i,j,k)+y(i,j,k)+z(i,j,k) .lt. 0.0d0) then
               dens(i,j,k) = 10.0
               tau(i,j,k)  = 20.0
               sx(i,j,k) = 0.0
               sy(i,j,k) = 0.0
               sz(i,j,k) = 0.0
            else
               dens(i,j,k) = 1.0
               tau(i,j,k)  = 1.0d-6
               sx(i,j,k) = 0.0
               sy(i,j,k) = 0.0
               sz(i,j,k) = 0.0
            endif
         enddo
         enddo
         enddo

      endif

      if (didit .eq. 0) then
         call CCTK_WARN(1,"Warning: shocktube did not set initial data")
      endif

c     initial guess for primative vars
      rho = dens
      press = (mahc_eos_gamma - 1.0d0)*tau
      eps = tau/rho

      gxx = 1.0d0
      gyy = 1.0d0
      gzz = 1.0d0
      gxy = 0.0d0
      gxz = 0.0d0
      gyz = 0.0d0


      return
      end