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)
     implicit none
   
     ! Layer thickness (h)
  
positive.code:   ! unless the external solver is used.
    integer :: nProcX, nProcY
  
    integer :: mpi_comm
    integer :: ierr
    integer :: num_procs, myid
  
  
negative.code:   integer*8 :: stencil
    integer :: ierr
    integer :: i ! loop variable
    integer*8 :: hypre_grid
    integer*8 :: hypre_A
    integer*8 :: hypre_b
    integer*8 :: hypre_x
  
    integer :: MPI_COMM_WORLD
  
    ! Time step loop variable
    integer :: n
  