anchor.diff:  
   ! ---------------------------------------------------------------------------
   
  +subroutine create_Hypre_grid(MPI_COMM_WORLD, hypre_grid, ilower, iupper, &
  +          num_procs, ierr)
  +
  +  integer, intent(in) :: MPI_COMM_WORLD
  +  integer*8 :: hypre_grid
  +  integer :: num_procs
  +  integer :: ilower(0:num_procs-1,2), iupper(0:num_procs-1,2)
  +
  +  call Hypre_StructGridCreate(MPI_COMM_WORLD, 2, hypre_grid, ierr)
  +
  +  !do i = 0, num_procs-1
  +  call HYPRE_StructGridSetExtents(hypre_grid, ilower(myid,:),iupper(myid,:), ierr)
  +  !end do
  +
  +  call HYPRE_StructGridAssemble(hypre_grid, ierr)
  +
  +  return
  +end subroutine create_Hypre_grid
  +
  +! ---------------------------------------------------------------------------
  +
   subroutine Ext_solver(hypre_A, MPI_COMM_WORLD, num_procs, & 
       ilower, iupper, etastar, &
       etanew, nx, ny, dt, hypre_grid, maxits, eps)
  
positive.code:   integer, dimension(:,:), allocatable :: ilower, iupper
    integer, dimension(:,:), allocatable :: jlower, jupper
    integer*8 :: hypre_grid
  #ifdef useExtSolver
    integer :: i, j
    integer   :: offsets(2,5)
  #endif
  
  
    ! Set default values here
  
negative.code: 
    namelist /MODEL/ hmean, depthFile, H0, RedGrav
  
    namelist /PRESSURE_SOLVER/ nProcX, nProcY
  
    namelist /SPONGE/ spongeHTimeScaleFile, spongeUTimeScaleFile, &
        spongeVTimeScaleFile, spongeHfile, spongeUfile, spongeVfile
  