mg_fill_ghost_cells_lvl Subroutine

  subroutine mg_fill_ghost_cells_lvl(mg, lvl, iv)

    type(mg_t)                   :: mg
    integer, intent(in)          :: lvl
    integer, intent(in)          :: iv
    !< Index of variable
    integer                      :: i, id, dsize, nc

    if (lvl < mg%lowest_lvl) error stop "fill_ghost_cells_lvl: lvl < lowest_lvl"
    if (lvl > mg%highest_lvl) error stop "fill_ghost_cells_lvl: lvl > highest_lvl"

    nc               = mg%box_size_lvl(lvl)

    if (lvl >= mg%first_normal_lvl) then
       dsize            = nc**(2-1)
       mg%buf(:)%i_send = 0
       mg%buf(:)%i_recv = 0
       mg%buf(:)%i_ix   = 0

       do i = 1, size(mg%lvls(lvl)%my_ids)
          id = mg%lvls(lvl)%my_ids(i)
          call buffer_ghost_cells(mg, id, nc, iv, .false.)
       end do

       if (lvl > 1) then
          do i = 1, size(mg%lvls(lvl-1)%my_ref_bnds)
             id = mg%lvls(lvl-1)%my_ref_bnds(i)
             call buffer_refinement_boundaries(mg, id, nc, iv, .false.)
          end do
       end if

       ! Transfer data between processes
       mg%buf(:)%i_recv = mg%comm_ghostcell%n_recv(:, lvl) * dsize
       call sort_and_transfer_buffers(mg, dsize)

       ! Set ghost cells to received data
       mg%buf(:)%i_recv = 0
    end if

    do i = 1, size(mg%lvls(lvl)%my_ids)
       id = mg%lvls(lvl)%my_ids(i)
       call set_ghost_cells(mg, id, nc, iv, .false.)
    end do
  end subroutine mg_fill_ghost_cells_lvl