mg_deallocate_storage Subroutine

  subroutine mg_deallocate_storage(mg)
    type(mg_t), intent(inout) :: mg
    integer                   :: lvl

    if (.not. mg%is_allocated) error stop "deallocate_storage: tree is not allocated"

    deallocate(mg%boxes)
    deallocate(mg%buf)

    deallocate(mg%comm_restrict%n_send)
    deallocate(mg%comm_restrict%n_recv)

    deallocate(mg%comm_prolong%n_send)
    deallocate(mg%comm_prolong%n_recv)

    deallocate(mg%comm_ghostcell%n_send)
    deallocate(mg%comm_ghostcell%n_recv)

    do lvl = mg%lowest_lvl, mg%highest_lvl
       deallocate(mg%lvls(lvl)%ids)
       deallocate(mg%lvls(lvl)%leaves)
       deallocate(mg%lvls(lvl)%parents)
       deallocate(mg%lvls(lvl)%ref_bnds)
       deallocate(mg%lvls(lvl)%my_ids)
       deallocate(mg%lvls(lvl)%my_leaves)
       deallocate(mg%lvls(lvl)%my_parents)
       deallocate(mg%lvls(lvl)%my_ref_bnds)
    end do

    mg%is_allocated       = .false.
    mg%n_boxes            = 0
    mg%phi_bc_data_stored = .false.
  end subroutine mg_deallocate_storage