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Merged
garth-wells merged 2 commits into from
Feb 28, 2026
Merged

Improve Topology code readability #4109

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Improve readability
garth-wells Aug 18, 2025
da7cbe5
Merge branch 'main' into garth/topology-readability
garth-wells Feb 28, 2026
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41 changes: 24 additions & 17 deletions cpp/dolfinx/mesh/Topology.cpp
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
// Copyright (C) 2006-2024 Anders Logg and Garth N. Wells
// Copyright (C) 2006-2025 Anders Logg and Garth N. Wells
//
// This file is part of DOLFINx (https://www.fenicsproject.org)
//
Expand Down Expand Up @@ -143,7 +143,6 @@ determine_sharing_ranks(MPI_Comm comm, std::span<const std::int64_t> indices)
// Find which ranks have each index
std::vector<std::int32_t> num_items_per_dest1(recv_disp0.size() - 1, 0);
std::vector<std::int32_t> num_items_per_pos1(recv_disp0.back(), 0);

std::vector<int> owner;
std::vector<int> disp1{0};
{
Expand Down Expand Up @@ -207,8 +206,7 @@ determine_sharing_ranks(MPI_Comm comm, std::span<const std::int64_t> indices)
auto indices_it1 = std::next(indices_it0, num_sharing_ranks);
for (std::int32_t j = disp1[i]; j < disp1[i + 1]; ++j)
{
auto& data1 = indices_list[j];
std::size_t pos = data1[1];
std::size_t pos = indices_list[j][1];
std::int32_t bufferpos = bdisp1[pos];
send_buffer1[bufferpos] = num_sharing_ranks;

Expand Down Expand Up @@ -729,8 +727,8 @@ build_entity_types(const std::vector<CellType>& cell_types)
// Find all facet types
std::set<mesh::CellType> e_types;
for (auto c : entity_types[tdim])
for (int i = 0; i < cell_num_entities(c, 2); ++i)
e_types.insert(cell_facet_type(c, i));
for (int i = 0; i < mesh::cell_num_entities(c, 2); ++i)
e_types.insert(mesh::cell_facet_type(c, i));
entity_types[2] = std::vector(e_types.begin(), e_types.end());
}
return entity_types;
Expand Down Expand Up @@ -778,7 +776,7 @@ Topology::Topology(
if (tdim == 1)
{
auto [cell_entity, entity_vertex, index_map, interprocess_entities]
= compute_entities(*this, 0, CellType::point, num_threads);
= mesh::compute_entities(*this, 0, CellType::point, num_threads);
std::ranges::sort(interprocess_entities);
_interprocess_facets.push_back(std::move(interprocess_entities));
}
Expand All @@ -796,11 +794,13 @@ const std::vector<CellType>& Topology::entity_types(int dim) const
//-----------------------------------------------------------------------------
mesh::CellType Topology::cell_type() const
{
std::vector<CellType> cell_types = entity_types(dim());
std::vector<CellType> cell_types = entity_types(this->dim());
if (cell_types.size() > 1)
{
throw std::runtime_error(
"Multiple cell types of this dimension. Call cell_types "
"instead.");
}
return cell_types.front();
}
//-----------------------------------------------------------------------------
Expand All @@ -825,15 +825,20 @@ Topology::index_maps(int dim) const
std::shared_ptr<const common::IndexMap> Topology::index_map(int dim) const
{
if (_entity_types[dim].size() > 1)
{
throw std::runtime_error(
"Multiple index maps of this dimension. Call index_maps instead.");
auto im = index_maps(dim);
}

std::vector<std::shared_ptr<const common::IndexMap>> im
= this->index_maps(dim);
if (im.empty())
{
throw std::runtime_error(std::format(
"Missing IndexMap in Topology. Maybe you need to create_entities({}).",
dim));
}

return im.at(0);
}
//-----------------------------------------------------------------------------
Expand Down Expand Up @@ -878,7 +883,7 @@ const std::vector<std::uint8_t>& Topology::get_facet_permutations() const
if (auto i_map = this->index_map(this->dim() - 1);
!i_map
or (_facet_permutations.empty()
and i_map->size_local() + i_map->num_ghosts() > 0))
and (i_map->size_local() + i_map->num_ghosts() > 0)))
{
throw std::runtime_error(
"create_entity_permutations must be called before using this data.");
Expand Down Expand Up @@ -910,7 +915,7 @@ bool Topology::create_entities(int dim, int num_threads)
for (int ent_type_idx = 0, num_ent_types = this->entity_types(dim).size();
ent_type_idx < num_ent_types; ++ent_type_idx)
{
if (!connectivity({dim, ent_type_idx}, {0, 0}))
if (!this->connectivity({dim, ent_type_idx}, {0, 0}))
{
entities_created = false;
break;
Expand All @@ -928,7 +933,7 @@ bool Topology::create_entities(int dim, int num_threads)

// Create local entities
auto [cell_entity, entity_vertex, index_map, interprocess_entities]
= compute_entities(*this, dim, *entity, num_threads);
= mesh::compute_entities(*this, dim, *entity, num_threads);
for (std::size_t k = 0; k < cell_entity.size(); ++k)
{
if (cell_entity[k])
Expand Down Expand Up @@ -959,8 +964,8 @@ bool Topology::create_entities(int dim, int num_threads)
void Topology::create_connectivity(int d0, int d1)
{
// Make sure entities exist
create_entities(d0);
create_entities(d1);
this->create_entities(d0);
this->create_entities(d1);

// Get the number of different entity types in each dimension
int num_d0 = this->entity_types(d0).size();
Expand All @@ -972,7 +977,8 @@ void Topology::create_connectivity(int d0, int d1)
for (int i1 = 0; i1 < num_d1; ++i1)
{
// Compute connectivity
auto [c_d0_d1, c_d1_d0] = compute_connectivity(*this, {d0, i0}, {d1, i1});
auto [c_d0_d1, c_d1_d0]
= mesh::compute_connectivity(*this, {d0, i0}, {d1, i1});

// NOTE: that to compute the (d0, d1) connections is it sometimes
// necessary to compute the (d1, d0) connections. We store the (d1,
Expand Down Expand Up @@ -1011,7 +1017,7 @@ void Topology::create_entity_permutations()
create_entities(d);

auto [facet_permutations, cell_permutations]
= compute_entity_permutations(*this);
= mesh::compute_entity_permutations(*this);
_facet_permutations = std::move(facet_permutations);
_cell_permutations = std::move(cell_permutations);
}
Expand Down Expand Up @@ -1044,7 +1050,7 @@ Topology mesh::create_topology(
std::vector<std::span<const std::int64_t>> ghost_cells;
for (std::size_t i = 0; i < cell_types.size(); i++)
{
int num_vertices = num_cell_vertices(cell_types[i]);
int num_vertices = mesh::num_cell_vertices(cell_types[i]);
if (cells[i].size() % num_vertices != 0)
{
throw std::runtime_error("Inconsistent number of cell vertices. Got "
Expand Down Expand Up @@ -1537,3 +1543,4 @@ mesh::compute_mixed_cell_pairs(const Topology& topology,

return facet_pair_lists;
}
//-----------------------------------------------------------------------------
5 changes: 2 additions & 3 deletions cpp/dolfinx/mesh/cell_types.h
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,6 @@

namespace dolfinx::mesh
{

/// Cell type identifier
enum class CellType : std::int8_t
{
Expand Down Expand Up @@ -120,8 +119,8 @@ inline CellType cell_entity_type(CellType type, int d, int index)
return CellType::point;
}

/// Return list of entities, where entities(e, k) is the local vertex
/// index for the kth vertex of entity e of dimension dim
/// @brief List of entities, where entity `(e, k)` is the local vertex
/// index for the `k`th vertex of entity `e` of dimension `dim`.
graph::AdjacencyList<int> get_entity_vertices(CellType type, int dim);

/// Get entities of dimension dim1 and that make up entities of dimension
Expand Down
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