anchor.diff:      values( ((i-1)*ny + j) )    = etastar(i,j)
       end do
     end do
  +
  +  do i = 0, num_procs-1
  +    call HYPRE_StructVectorSetBoxValues(hypre_b, & 
  +      ilower(i,:), iupper(i,:), values, ierr)
  +  end do
  +
  +  call HYPRE_StructVectorAssemble(hypre_b, ierr)
   
   #endif
   
  
positive.code:   call HYPRE_StructVectorCreate(MPI_COMM_WORLD, hypre_grid, hypre_b, ierr)
    call HYPRE_StructVectorInitialize(hypre_b, ierr)
  
    do i = 1, nx ! loop over every grid point
      do j = 1, ny
    ! the 2D array is being laid out like
  
negative.code:   integer*8 :: hypre_b
    integer*8 :: hypre_x
    integer   ::  nentries, nvalues, stencil_indices(5)
    double precision :: values(nx * ny)
  
    integer :: MPI_COMM_WORLD
    integer :: num_procs
  