anchor.diff:      maxits, eps, rjac, freesurfFac, thickness_error, &
       g_vec, nx, ny, layers, n, &
        MPI_COMM_WORLD, myid, num_procs, ilower, iupper, & 
  -     hypre_grid, hypre_b, ierr)
  +     hypre_grid, hypre_A, ierr)
        ! , &
       ! hypre_grid, hypre_A, hypre_b, hypre_x)
     implicit none
  
positive.code:           maxits, eps, rjac, freesurfFac, thickness_error, &
            g_vec, nx, ny, layers, n, &
            MPI_COMM_WORLD, myid, num_procs, ilower, iupper, &
            hypre_grid, hypre_b, ierr)
            ! , &
            ! MPI_COMM_WORLD, num_procs, ilower, iupper, &
            ! hypre_grid, hypre_A, hypre_b, hypre_x)
      end if
  
  
  
negative.code:   integer :: num_procs, myid
    integer :: ilower(0:num_procs-1,2), iupper(0:num_procs-1,2)
  
    ! Calculate the barotropic velocities
    call calc_baro_u(ub, unew, hnew, eta, freesurfFac, nx, ny, layers)
    call calc_baro_v(vb, vnew, hnew, eta, freesurfFac, nx, ny, layers)
  