anchor.diff:    ! External solver variables
     integer   :: offsets(2,5)
     integer :: i, j ! loop variables
  -  integer   ::  nentries, nvalues, stencil_indices(5)
     double precision, dimension(:), allocatable :: values
     integer   :: indicies(2)
     integer*8 :: hypre_grid
  
positive.code:           num_procs, myid, ierr)
    implicit none
  
    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)
    integer :: myid
    integer :: ierr
  
  #ifdef useExtSolver
    call Hypre_StructGridCreate(MPI_COMM_WORLD, 2, hypre_grid, ierr)
  
negative.code:           a, nx, ny, freesurfFac, dt, ierr)
    implicit none
  
    integer,          intent(in)  :: MPI_COMM_WORLD
    integer*8,        intent(in)  :: hypre_grid
    integer*8,        intent(out) :: hypre_A
    double precision, intent(in)  :: a(5, nx, ny)
    integer,          intent(in)  :: nx, ny
    double precision, intent(in)  :: freesurfFac
    double precision, intent(in)  :: dt
    integer,          intent(out) :: ierr
  
    ! Hypre stencil for creating the A matrix
    integer*8 :: stencil
  
    integer :: offsets(2,5)
  