anchor.diff:        base_wind_x, base_wind_y, wind_mag_time_series, &
         spongeHTimeScale, spongeUTimeScale, spongeVTimeScale, &
         spongeH, spongeU, spongeV, &
  -      nx, ny, layers, RedGrav, DumpWind)
  +      nx, ny, layers, RedGrav, DumpWind, &
  +      MPI_COMM_WORLD, hypre_grid)
     print *, 'Execution ended normally'
     stop 0
   end program aronnax
  
positive.code:   integer*8 :: stencil
    integer :: ierr
    integer :: i ! loop variable
    integer*8 :: hypre_A
    integer*8 :: hypre_b
    integer*8 :: hypre_x
  
    ! Time step loop variable
    integer :: n
  
negative.code:       call HYPRE_StructStencilSetElement(stencil, i, offsets(:,i),ierr) 
      end do
  
      call HYPRE_StructMatrixCreate(MPI_COMM_WORLD, hypre_grid, stencil, hypre_A, ierr)
      call HYPRE_StructMatrixInitialize(hypre_A, ierr)
  
  ! ilower(myid,1), & 
  !            iupper(myid,1), ilower(myid,2), iupper(myid,2)
  