Method adjust_indices

cpp/dolfinx/refinement/utils.cpp:102–151

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}
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std::vector<std::int64_t>
refinement::adjust_indices(const common::IndexMap& map, std::int32_t n)
{
  // NOTE: Is this effectively concatenating index maps?

  // Get offset for 'n' for this process
  const std::int64_t num_local = n;
  std::int64_t global_offset = 0;
  MPI_Exscan(&num_local, &global_offset, 1, MPI_INT64_T, MPI_SUM, map.comm());

  std::span owners = map.owners();
  std::span src = map.src();
  std::span dest = map.dest();

  MPI_Comm comm;
  MPI_Dist_graph_create_adjacent(map.comm(), src.size(), src.data(),
                                 MPI_UNWEIGHTED, dest.size(), dest.data(),
                                 MPI_UNWEIGHTED, MPI_INFO_NULL, false, &comm);

  // Communicate offset to neighbors
  std::vector<std::int64_t> offsets(src.size(), 0);
  offsets.reserve(1);
  MPI_Neighbor_allgather(&global_offset, 1, MPI_INT64_T, offsets.data(), 1,
                         MPI_INT64_T, comm);

  MPI_Comm_free(&comm);

  int local_size = map.size_local();
  std::vector<std::int64_t> global_indices = map.global_indices();

  // Add new offset to owned indices
  std::transform(global_indices.begin(),
                 std::next(global_indices.begin(), local_size),
                 global_indices.begin(),
                 [global_offset](auto x) { return x + global_offset; });

  // Add offsets to ghost indices
  std::transform(std::next(global_indices.begin(), local_size),
                 global_indices.end(), owners.begin(),
                 std::next(global_indices.begin(), local_size),
                 [&src, &offsets](auto idx, auto r)
                 {
                   auto it = std::ranges::lower_bound(src, r);
                   assert(it != src.end() and *it == r);
                   int rank = std::distance(src.begin(), it);
                   return idx + offsets[rank];
                 });

  return global_indices;
}
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std::array<std::vector<std::int32_t>, 2> refinement::transfer_facet_meshtag(
    const mesh::MeshTags<std::int32_t>& tags0, const mesh::Topology& topology1,