compute_connections Subroutine

  subroutine compute_connections(itleft, itright, connections)
    use gs2_layouts, only: g_lo, il_idx, ik_idx, it_idx, ie_idx, is_idx, proc_id, idx
    use le_grids, only: il_is_trapped, il_is_wfb, trapped_wfb
    implicit none
    integer, dimension(:, :), intent(in) :: itleft, itright
    type(connections_type), dimension(g_lo%llim_proc:), intent(out) :: connections
    integer :: iglo, il, ik, it, ie, is, iglo_connection

    ! Note connections_type have initial values reflecting no connections
    ! so we don't need to explicitly populate every instance.

    !$OMP PARALLEL DO DEFAULT(none) &
    !$OMP PRIVATE(iglo, il, ik, it, ie, is, iglo_connection) &
    !$OMP SHARED(g_lo, itleft, itright, connections, trapped_wfb) &
    !$OMP SCHEDULE(static)
    do iglo = g_lo%llim_proc, g_lo%ulim_proc
       ! get processors and indices for j' (kx') modes connecting
       ! to mode j (kx) so we can set up communication -- MAB

       il = il_idx(g_lo,iglo)

       ! if non-wfb trapped particle, no connections
       ! or if wfb is trapped, no connections
       if (il_is_trapped(il) .or. (il_is_wfb(il) .and. trapped_wfb)) cycle

       ik = ik_idx(g_lo,iglo)
       it = it_idx(g_lo,iglo)

       ! If no links then cycle
       if (itleft(it, ik) < 0 .and. itright(it, ik) < 0) cycle

       ie = ie_idx(g_lo,iglo)
       is = is_idx(g_lo,iglo)

       if (itleft(it, ik) >= 0) then
          iglo_connection = idx(g_lo, ik, itleft(it, ik), il, ie, is)
          connections(iglo)%iproc_left = proc_id(g_lo, iglo_connection)
          connections(iglo)%iglo_left = iglo_connection
          connections(iglo)%neighbor = .true.
       end if

       if (itright(it, ik) >= 0) then
          iglo_connection = idx(g_lo, ik, itright(it, ik), il, ie, is)
          connections(iglo)%iproc_right = proc_id(g_lo, iglo_connection)
          connections(iglo)%iglo_right = iglo_connection
          connections(iglo)%neighbor = .true.
       end if
    end do
    !$OMP END PARALLEL DO
  end subroutine compute_connections