anchor.diff:    call MPI_INIT(ierr)
     call MPI_COMM_RANK(MPI_COMM_WORLD, myid, ierr)
     call MPI_COMM_SIZE(MPI_COMM_WORLD, num_procs, ierr)
  -  mpi_comm = MPI_COMM_WORLD
  +  ! mpi_comm = MPI_COMM_WORLD
   
     if (num_procs .ne. nProcX * nProcY) then
       if (myid .eq. 0) then
  
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)
  