create_allParentNeighbors Subroutine

  recursive subroutine create_allParentNeighbors(                          &
    &                           targetID, level, stencil, tree, levelDesc, &
    &                           pathFirst, pathLast, proc                  )
    ! -------------------------------------------------------------------- !
    !> requested element position (child element) in LevelDesc elem list
    integer(kind=long_k), intent(in) :: targetID
    !> requested element level
    integer, intent(in) :: level
    !> first treeID path in every process
    type(tem_path_type), intent(in) :: pathFirst(:)
    !> last treeID path in every process
    type(tem_path_type), intent(in) :: pathLast(:)
    !> tree information
    type(treelmesh_type), intent(in) :: tree
    !> the level descriptor to be filled
    type(tem_levelDesc_type), intent(inout) :: levelDesc(tree%global%minLevel:)
    !> process
    type(tem_comm_env_type), intent(in) :: proc
    !> current stencil definition
    type(tem_stencilHeader_type), intent(in) :: stencil
    ! -------------------------------------------------------------------- !
    integer(kind=long_k) :: parentID, neighID  ! current tree ID
    integer :: coarserLevel, cPos, parentNesting, addedPos, iStencilElem
    integer :: neighIDpos
    ! -------------------------------------------------------------------- !

    ! exit if we have reached the minimal level
    if ( level == tree%global%minlevel ) return

    ! Get the parent of the current treeID
    parentID = tem_parentOf( targetID )

    ! ... and identify the parent
    parentNesting = -1
    call identify_elements( TreeID     = parentID,  &
      &                     tree       = tree,      &
      &                     pathFirst  = pathFirst, &
      &                     pathLast   = pathLast,  &
      &                     levelDesc  = levelDesc, &
      &                     elemPos    = cPos,      &
      &                     proc       = proc,      &
      &                     stencil    = stencil,   &
      &                     nesting    = -1         )

    if ( cPos <= 0 ) then
      write(dbgUnit(3),*) ' Element not found: ', parentID
      write(dbgUnit(3),*) '              cPos: ', cPos
    end if

    ! identify the stencil neighbors of the parent.
    ! Here we should identify the fromCoarser interpolation stencil neighbors
    ! instead of the compute stencil neighbors
    coarserLevel = level - 1
    call identify_stencilNeigh( iElem     = cPos,         &
      &                         iLevel    = coarserLevel, &
      &                         tree      = tree,         &
      &                         iStencil  = 1,            &
      &                         pathFirst = pathFirst,    &
      &                         pathLast  = pathLast,     &
      &                         levelDesc = levelDesc,    &
      &                         proc      = proc,         &
      &                         stencil   = stencil,      &
      &                         nesting   = parentNesting )
      
    ! adding neighs of neighs for interpolation at ML
    ! this is for the stencil of the fine ghost, composed by coarse fluid 
    do iStencilElem = 1, stencil%QQN
    
      neighIDpos = levelDesc(coarserLevel)%elem%stencil%val(cPos)    &
        &                           %val(1)%tIDpos(iStencilElem)
      if( neighIDpos > 0 ) then
        neighID = &
          & levelDesc( coarserLevel )%elem%neighID%val(cPos)%val(neighIDpos)
        ! This call might add new halo elements
        if ( neighID > 0_long_k ) then
          call append( me       = levelDesc( coarserLevel )%require, &
            &          val      = neighID,                           &
            &          pos      = addedPos )
        end if
      end if ! neighIDpos > 0
    enddo

  end subroutine create_allParentNeighbors