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// Copyright (C) 2025 Jørgen S. Dokken and Joseph P. Dean
//
// This file is part of DOLFINx (https://www.fenicsproject.org)
//
// SPDX-License-Identifier: LGPL-3.0-or-later
#include "EntityMap.h"
#include "Topology.h"
#include <ranges>
#include <span>
#include <unordered_map>
#include <vector>
namespace dolfinx::mesh
{
//-----------------------------------------------------------------------------
std::size_t EntityMap::dim() const { return _dim; }
//-----------------------------------------------------------------------------
std::shared_ptr<const Topology> EntityMap::topology() const
{
return _topology;
}
//-----------------------------------------------------------------------------
std::shared_ptr<const Topology> EntityMap::sub_topology() const
{
return _sub_topology;
}
//-----------------------------------------------------------------------------
std::vector<std::int32_t>
EntityMap::sub_topology_to_topology(std::span<const std::int32_t> entities,
bool inverse) const
{
if (!inverse)
{
// In this case, we want to map from entity indices in
// `_sub_topology` to corresponding entities in `_topology`. Hence,
// for each index in `entities`, we get the corresponding index in
// `_topology` using `_sub_topology_to_topology`
auto mapped
= entities
| std::views::transform([this](std::int32_t i)
{ return _sub_topology_to_topology[i]; });
return std::vector<std::int32_t>(mapped.begin(), mapped.end());
}
else
{
// In this case, we are mapping from entity indices in `_topology`
// to entity indices in `_sub_topology`. Hence, we first need to
// construct the "inverse" of `_sub_topology_to_topology`
std::unordered_map<std::int32_t, std::int32_t> topology_to_sub_topology;
topology_to_sub_topology.reserve(_sub_topology_to_topology.size());
for (std::size_t i = 0; i < _sub_topology_to_topology.size(); ++i)
topology_to_sub_topology.insert({_sub_topology_to_topology[i], i});
// For each entity index in `entities` (which are indices in
// `_topology`), get the corresponding entity in `_sub_topology`.
// Since `_sub_topology` consists of a subset of entities in
// `_topology`, there are entities in topology that may not exist in
// `_sub_topology`. If this is the case, mark those entities with
// -1.
auto mapped
= entities
| std::views::transform(
[&topology_to_sub_topology](std::int32_t i)
{
// Map the entity if it exists. If it doesn't, mark with
// -1.
auto it = topology_to_sub_topology.find(i);
return (it != topology_to_sub_topology.end()) ? it->second : -1;
});
return std::vector<std::int32_t>(mapped.begin(), mapped.end());
}
}
//-----------------------------------------------------------------------------
} // namespace dolfinx::mesh
|
