EdgeUniqueIdBuilder.cc

// -*- tab-width: 2; indent-tabs-mode: nil; coding: utf-8-with-signature -*-
//-----------------------------------------------------------------------------
// Copyright 2000-2026 CEA (www.cea.fr) IFPEN (www.ifpenergiesnouvelles.com)
// See the top-level COPYRIGHT file for details.
// SPDX-License-Identifier: Apache-2.0
//-----------------------------------------------------------------------------
/*---------------------------------------------------------------------------*/
/* EdgeUniqueIdBuilder.cc                                      (C) 2000-2025 */
/*                                                                           */
/* Construction of unique edge identifiers.                                  */
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
#include "arcane/utils/PlatformUtils.h"
#include "arcane/utils/ScopedPtr.h"
#include "arcane/utils/ITraceMng.h"
#include "arcane/utils/OStringStream.h"
 
#include "arcane/mesh/DynamicMesh.h"
#include "arcane/mesh/EdgeUniqueIdBuilder.h"
#include "arcane/mesh/GhostLayerBuilder.h"
#include "arcane/mesh/OneMeshItemAdder.h"
#include "arcane/mesh/ItemsOwnerBuilder.h"
 
#include "arcane/core/IParallelExchanger.h"
#include "arcane/core/IParallelMng.h"
#include "arcane/core/ISerializeMessage.h"
#include "arcane/core/ISerializer.h"
#include "arcane/core/ParallelMngUtils.h"
#include "arcane/core/IMeshUniqueIdMng.h"
 
#include <functional>
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
namespace Arcane::mesh
{
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
EdgeUniqueIdBuilder::
EdgeUniqueIdBuilder(DynamicMeshIncrementalBuilder* mesh_builder)
: TraceAccessor(mesh_builder->mesh()->traceMng())
, m_mesh(mesh_builder->mesh())
, m_mesh_builder(mesh_builder)
{
}
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
void EdgeUniqueIdBuilder::
computeEdgesUniqueIds()
{
  double begin_time = platform::getRealTime();
 
  Int32 edge_version = m_mesh->meshUniqueIdMng()->edgeBuilderVersion();
 
  info() << "Using version=" << edge_version << " to compute edges unique ids"
         << " mesh=" << m_mesh->name();
  bool need_compute_owner = false;
  bool has_renumbering = true;
  if (edge_version == 1)
    _computeEdgesUniqueIdsParallel3();
  else if (edge_version == 2)
    _computeEdgesUniqueIdsParallelV2();
  else if (edge_version == 3) {
    need_compute_owner = true;
    _computeEdgesUniqueIdsParallel64bit();
  }
  else if (edge_version == 0) {
    need_compute_owner = true;
    has_renumbering = false;
    info() << "No renumbering for edges";
  }
  else
    ARCANE_FATAL("Invalid valid version '{0}'. Valid values are 0, 1, 2 or 3");
 
  double end_time = platform::getRealTime();
  Real diff = static_cast<Real>(end_time - begin_time);
  info() << "TIME to compute edge unique ids=" << diff;
 
  ItemInternalMap& edges_map = m_mesh->edgesMap();
 
  // The #m_edges_map must be re-indexed if the uniqueId() of the
  // edges have been modified.
  if (has_renumbering)
    edges_map.notifyUniqueIdsChanged();
 
  if (m_mesh_builder->isVerbose()) {
    info() << "NEW EDGES_MAP after re-indexing";
    edges_map.eachItem([&](Item edge) {
      info() << "Edge uid=" << edge.uniqueId() << " lid=" << edge.localId();
    });
  }
 
  // If there is no renumbering, there is no
  // owner calculation. It must therefore be done now
  // if we are in parallel.
  if (need_compute_owner && m_mesh->parallelMng()->isParallel()) {
    ItemsOwnerBuilder owner_builder(m_mesh);
    owner_builder.computeEdgesOwner();
  }
}
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
class T_CellEdgeInfo
{
 public:
 
  T_CellEdgeInfo(Int64 uid, Integer nb_back_edge, Integer nb_true_boundary_edge)
  : m_unique_id(uid)
  , m_nb_back_edge(nb_back_edge)
  , m_nb_true_boundary_edge(nb_true_boundary_edge)
  {
  }
 
  T_CellEdgeInfo()
  : m_unique_id(NULL_ITEM_ID)
  , m_nb_back_edge(0)
  , m_nb_true_boundary_edge(0)
  {
  }
 
 public:
 
  bool operator<(const T_CellEdgeInfo& ci) const
  {
    return m_unique_id < ci.m_unique_id;
  }
 
 public:
 
  Int64 m_unique_id;
  Int64 m_nb_back_edge;
  Int64 m_nb_true_boundary_edge;
};
 
template <typename DataType>
class ItemInfoMultiList
{
 public:
 private:
 
  class MyInfo
  {
   public:
 
    MyInfo(const DataType& d, Integer n)
    : data(d)
    , next_index(n)
    {}
 
   public:
 
    DataType data;
    Integer next_index;
  };
 
 public:
 
  ItemInfoMultiList()
  : m_last_index(5000, true)
  {}
 
 public:
 
  void add(Int64 node_uid, const DataType& data)
  {
    Integer current_index = m_values.size();
 
    bool is_add = false;
    HashTableMapT<Int64, Int32>::Data* d = m_last_index.lookupAdd(node_uid, -1, is_add);
 
    m_values.add(MyInfo(data, d->value()));
    d->value() = current_index;
  }
 
 public:
 
  UniqueArray<MyInfo> m_values;
  HashTableMapT<Int64, Int32> m_last_index;
};
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
class Parallel3EdgeUniqueIdBuilder
: public TraceAccessor
{
  using BoundaryInfosMap = std::unordered_map<Int32, SharedArray<Int64>>;
 
 public:
 
  Parallel3EdgeUniqueIdBuilder(ITraceMng* tm, DynamicMeshIncrementalBuilder* mesh_builder,
                               Int64 max_node_uid);
 
 public:
 
  void compute();
 
 private:
 
  DynamicMesh* m_mesh = nullptr;
  DynamicMeshIncrementalBuilder* m_mesh_builder = nullptr;
  IParallelMng* m_parallel_mng = nullptr;
  const Int32 m_my_rank = A_NULL_RANK;
  const Int32 m_nb_rank = A_NULL_RANK;
  BoundaryInfosMap m_boundary_infos_to_send;
  NodeUidToSubDomain m_uid_to_subdomain_converter;
  std::unordered_map<Int64, SharedArray<Int64>> m_nodes_info;
  UniqueArray<bool> m_is_boundary_nodes;
  bool m_is_verbose = false;
 
 private:
 
  void _exchangeData(IParallelExchanger* exchanger);
  void _addEdgeBoundaryInfo(Edge edge);
  void _computeEdgesUniqueId();
  void _sendInfosToOtherRanks();
};
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
Parallel3EdgeUniqueIdBuilder::
Parallel3EdgeUniqueIdBuilder(ITraceMng* tm, DynamicMeshIncrementalBuilder* mesh_builder, Int64 max_node_uid)
: TraceAccessor(tm)
, m_mesh(mesh_builder->mesh())
, m_mesh_builder(mesh_builder)
, m_parallel_mng(m_mesh->parallelMng())
, m_my_rank(m_parallel_mng->commRank())
, m_nb_rank(m_parallel_mng->commSize())
, m_uid_to_subdomain_converter(max_node_uid, m_nb_rank)
, m_is_verbose(m_mesh_builder->isVerbose())
{
}
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
void Parallel3EdgeUniqueIdBuilder::
_exchangeData(IParallelExchanger* exchanger)
{
  for (const auto& [key, value] : m_boundary_infos_to_send) {
    exchanger->addSender(key);
  }
  exchanger->initializeCommunicationsMessages();
  {
    for (Integer i = 0, ns = exchanger->nbSender(); i < ns; ++i) {
      ISerializeMessage* sm = exchanger->messageToSend(i);
      Int32 rank = sm->destination().value();
      ISerializer* s = sm->serializer();
      ConstArrayView<Int64> infos = m_boundary_infos_to_send[rank];
      Integer nb_info = infos.size();
      s->setMode(ISerializer::ModeReserve);
      s->reserveInt64(1); // For the number of elements
      s->reserveSpan(eBasicDataType::Int64, nb_info); // For the elements
      s->allocateBuffer();
      s->setMode(ISerializer::ModePut);
      //info() << " SEND1 rank=" << rank << " nb_info=" << nb_info;
      s->putInt64(nb_info);
      s->putSpan(infos);
    }
  }
  exchanger->processExchange();
  debug() << "END EXCHANGE";
}
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
void Parallel3EdgeUniqueIdBuilder::
_addEdgeBoundaryInfo(Edge edge)
{
  Node first_node = edge.node(0);
  Int64 first_node_uid = first_node.uniqueId();
  SharedArray<Int64> v;
  Int32 dest_rank = -1;
  if (!m_is_boundary_nodes[first_node.localId()]) {
    v = m_nodes_info[first_node_uid];
  }
  else {
    dest_rank = m_uid_to_subdomain_converter.uidToRank(first_node_uid);
    v = m_boundary_infos_to_send[dest_rank];
  }
  v.add(first_node_uid); // 0
  v.add(m_my_rank); // 1
  v.add(edge.uniqueId()); // 2
  v.add(edge.type()); // 3
  v.add(NULL_ITEM_UNIQUE_ID); // 4 : only used for debug
  v.add(NULL_ITEM_UNIQUE_ID); // 5 : only used for debug
  if (m_is_verbose)
    info() << "Edge uid=" << edge.uniqueId() << " n0,n1=" << edge.node(0).uniqueId() << "," << edge.node(1).uniqueId()
           << " n0=" << ItemPrinter(edge.node(0)) << " n1=" << ItemPrinter(edge.node(1)) << " dest_rank=" << dest_rank;
  for (Node edge_node : edge.nodes())
    v.add(edge_node.uniqueId());
}
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
void Parallel3EdgeUniqueIdBuilder::
compute()
{
  IParallelMng* pm = m_mesh->parallelMng();
 
  Integer nb_local_edge = m_mesh_builder->oneMeshItemAdder()->nbEdge();
  info() << "ComputeEdgesUniqueIdsParallel3 nb_edge=" << nb_local_edge;
 
  UniqueArray<Int64> edges_opposite_cell_uid(nb_local_edge);
  edges_opposite_cell_uid.fill(NULL_ITEM_ID);
  UniqueArray<Int32> edges_opposite_cell_index(nb_local_edge);
  UniqueArray<Int32> edges_opposite_cell_owner(nb_local_edge);
 
  // For verification, ensures that all elements of this array
  // are valid, which means that all edges have been
  // renumbered.
  UniqueArray<Int64> edges_new_uid(nb_local_edge);
  edges_new_uid.fill(NULL_ITEM_UNIQUE_ID);
 
  UniqueArray<Int64> edges_infos;
  edges_infos.reserve(10000);
  ItemInternalMap& edges_map = m_mesh->edgesMap();
  ItemInternalMap& faces_map = m_mesh->facesMap(); // used to detect the boundary
 
  // NOTE: this array is not useful on all cells. It
  // is enough that it contains the cells we need, that is
  // ours + those connected to one of our edges.
  HashTableMapT<Int32, Int32> cell_first_edge_uid(m_mesh_builder->oneMeshItemAdder()->nbCell() * 2, true);
 
  // Gather data from other processors into recv_cells;
  // To prevent the arrays from being too large, we proceed in several
  // steps.
  // Each sub-domain builds its list of boundary edges, for each
  // edge:
  //  - its type,
  //  - the list of its nodes,
  //  - the unique number of its cell,
  //  - the owner of its cell,
  //  - its index in its cell,
  // This list will then be sent to all sub-domains.
 
  IItemFamily* node_family = m_mesh->nodeFamily();
  m_is_boundary_nodes.resize(node_family->maxLocalId(), false);
 
  // Marks all boundary nodes, because these are the ones that need to be sent
  // A node is considered boundary if it belongs to a face that has only one
  // connected cell.
  faces_map.eachItem([&](Face face) {
    Integer face_nb_cell = face.nbCell();
    if (face_nb_cell == 1) {
      for (Int32 ilid : face.nodeIds())
        m_is_boundary_nodes[ilid] = true;
    }
  });
 
  // Determines the list of boundary edges.
  // The order of this list depends on the hash table implementation.
  // To have the same numbering as the historical version (which uses HashTableMapT),
  // we use a temporary instance of this class for this calculation if
  // the implementation used is different. This is the case starting from October 2024.
  // Eventually, another version of the uniqueId() calculation for
  // edges should be used.
  // TODO: This mechanism is under test. Verify that this subsequently
  // gives the same numbering.
  const bool is_new_item_map_impl = ItemInternalMap::UseNewImpl;
  if (is_new_item_map_impl) {
    info() << "Edge: ItemInternalMap is using new implementation";
    HashTableMapT<Int64, Edge> old_edges_map(5000, false);
    edges_map.eachItem([&](Edge edge) {
      old_edges_map.add(edge.uniqueId(), edge);
    });
    old_edges_map.eachValue([&](Edge edge) {
      _addEdgeBoundaryInfo(edge);
    });
  }
  else {
    edges_map.eachItem([&](Edge edge) {
      _addEdgeBoundaryInfo(edge);
    });
  }
 
  _computeEdgesUniqueId();
  _sendInfosToOtherRanks();
 
  traceMng()->flush();
  pm->barrier();
  info() << "END OF TEST NEW EDGE COMPUTE";
}
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
void Parallel3EdgeUniqueIdBuilder::
_computeEdgesUniqueId()
{
  ItemTypeMng* itm = m_mesh->itemTypeMng();
  IParallelMng* pm = m_parallel_mng;
  Ref<IParallelExchanger> exchanger{ ParallelMngUtils::createExchangerRef(pm) };
  _exchangeData(exchanger.get());
 
  Integer nb_receiver = exchanger->nbReceiver();
  debug() << "NB RECEIVER=" << nb_receiver;
  SharedArray<Int64> received_infos;
  for (Integer i = 0; i < nb_receiver; ++i) {
    ISerializeMessage* sm = exchanger->messageToReceive(i);
    //Int32 orig_rank = sm->destSubDomain();
    ISerializer* s = sm->serializer();
    s->setMode(ISerializer::ModeGet);
    Int64 nb_info = s->getInt64();
    //info() << "RECEIVE NB_INFO=" << nb_info << " from=" << orig_rank;
    received_infos.resize(nb_info);
    s->getSpan(received_infos);
    //if ((nb_info % 3)!=0)
    //fatal() << "info size can not be divided by 3";
    Integer z = 0;
    while (z < nb_info) {
      Int64 node_uid = received_infos[z + 0];
      //Int64 sender_rank = received_infos[z+1];
      //Int64 edge_uid = received_infos[z+2];
      Int32 edge_type = (Int32)received_infos[z + 3];
      // received_infos[z+4];
      // received_infos[z+5];
      ItemTypeInfo* itt = itm->typeFromId(edge_type);
      Integer edge_nb_node = itt->nbLocalNode();
      Int64Array& a = m_nodes_info[node_uid];
      a.addRange(Int64ConstArrayView(6 + edge_nb_node, &received_infos[z]));
      z += 6;
      z += edge_nb_node;
      //info() << "NODE UID=" << node_uid << " sender=" << sender_rank
      //       << " edge_uid=" << edge_uid;
      //node_cell_list.add(node_uid,cell_uid,cell_owner);
      //HashTableMapT<Int64,Int32>::Data* v = nodes_nb_cell.lookupAdd(node_uid);
      //++v->value();
    }
  }
 
  Integer my_max_edge_node = 0;
  for (const auto& [key, value] : m_nodes_info) {
    //Int64 key = inode.data()->key();
    Int64ConstArrayView a = value;
    //info() << "A key=" << key << " size=" << a.size();
    Integer nb_info = a.size();
    Integer z = 0;
    Integer node_nb_edge = 0;
    while (z < nb_info) {
      ++node_nb_edge;
      //Int64 node_uid = a[z+0];
      //Int64 sender_rank = a[z+1];
      //Int64 edge_uid = a[z+2];
      Int32 edge_type = (Int32)a[z + 3];
      // a[z+4];
      // a[z+5];
      ItemTypeInfo* itt = itm->typeFromId(edge_type);
      Integer edge_nb_node = itt->nbLocalNode();
      /*info() << "NODE2 UID=" << node_uid << " sender=" << sender_rank
          << " edge_uid=" << edge_uid */
      //for( Integer y=0; y<edge_nb_node; ++y )
      //info() << "Nodes = i="<< y << " " << a[z+6+y];
      z += 6;
      z += edge_nb_node;
    }
    my_max_edge_node = math::max(node_nb_edge, my_max_edge_node);
  }
  Integer global_max_edge_node = pm->reduce(Parallel::ReduceMax, my_max_edge_node);
  debug() << "GLOBAL MAX EDGE NODE=" << global_max_edge_node;
  // OK, maintenant donne comme uid de la edge (node_uid * global_max_edge_node + index)
  IntegerUniqueArray indexes;
  m_boundary_infos_to_send.clear();
 
  for (const auto& [key, value] : m_nodes_info) {
    Int64ConstArrayView a = value;
    Integer nb_info = a.size();
    Integer z = 0;
    Integer node_nb_edge = 0;
    indexes.clear();
    while (z < nb_info) {
      Int64 node_uid = a[z + 0];
      Int32 sender_rank = (Int32)a[z + 1];
      Int64 edge_uid = a[z + 2];
      Int32 edge_type = (Int32)a[z + 3];
      // a[z+4];
      // a[z+5];
      ItemTypeInfo* itt = itm->typeFromId(edge_type);
      Integer edge_nb_node = itt->nbLocalNode();
 
      // Regarde si la edge est déjà dans la liste:
      Integer edge_index = node_nb_edge;
      Int32 edge_new_owner = sender_rank;
      for (Integer y = 0; y < node_nb_edge; ++y) {
        if (memcmp(&a[indexes[y] + 6], &a[z + 6], sizeof(Int64) * edge_nb_node) == 0) {
          edge_index = y;
          edge_new_owner = (Int32)a[indexes[y] + 1];
        }
      }
      Int64 edge_new_uid = (node_uid * global_max_edge_node) + edge_index;
      Int64Array& v = m_boundary_infos_to_send[sender_rank];
      // Indicates to the owner of this edge its new uid
      v.add(edge_uid);
      v.add(edge_new_uid);
      v.add(edge_new_owner);
      indexes.add(z);
      z += 6;
      z += edge_nb_node;
      /* info() << "NODE3 UID=" << node_uid << " sender=" << sender_rank
               << " edge_uid=" << edge_uid
               << " edge_index=" << edge_index
               << " edge_new_uid=" << edge_new_uid; */
      ++node_nb_edge;
    }
    my_max_edge_node = math::max(node_nb_edge, my_max_edge_node);
  }
}
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
void Parallel3EdgeUniqueIdBuilder::
_sendInfosToOtherRanks()
{
  const bool is_verbose = m_mesh_builder->isVerbose();
  IParallelMng* pm = m_parallel_mng;
  Ref<IParallelExchanger> exchanger = ParallelMngUtils::createExchangerRef(pm);
 
  _exchangeData(exchanger.get());
 
  ItemInternalMap& edges_map = m_mesh->edgesMap();
  Integer nb_receiver = exchanger->nbReceiver();
  debug() << "NB RECEIVER=" << nb_receiver;
  Int64UniqueArray received_infos;
  for (Integer i = 0; i < nb_receiver; ++i) {
    ISerializeMessage* sm = exchanger->messageToReceive(i);
    auto orig_rank = sm->destination();
    ISerializer* s = sm->serializer();
    s->setMode(ISerializer::ModeGet);
    Int64 nb_info = s->getInt64();
    if (is_verbose)
      info() << "RECEIVE NB_INFO=" << nb_info << " from=" << orig_rank;
    received_infos.resize(nb_info);
    s->getSpan(received_infos);
    if ((nb_info % 3) != 0)
      ARCANE_FATAL("info size can not be divided by 3 x={0}", nb_info);
    Int64 nb_item = nb_info / 3;
    for (Int64 z = 0; z < nb_item; ++z) {
      Int64 old_uid = received_infos[(z * 3)];
      Int64 new_uid = received_infos[(z * 3) + 1];
      Int32 new_owner = static_cast<Int32>(received_infos[(z * 3) + 2]);
      //info() << "EDGE old_uid=" << old_uid << " new_uid=" << new_uid;
      impl::MutableItemBase iedge(edges_map.tryFind(old_uid));
      if (iedge.null())
        ARCANE_FATAL("Can not find own edge uid={0}", old_uid);
      iedge.setUniqueId(new_uid);
      iedge.setOwner(new_owner, m_my_rank);
      Edge edge{ iedge };
      if (is_verbose)
        info() << "SetEdgeOwner uid=" << new_uid << " owner=" << new_owner
               << " n0,n1=" << edge.node(0).uniqueId() << "," << edge.node(1).uniqueId()
               << " n0=" << ItemPrinter(edge.node(0)) << " n1=" << ItemPrinter(edge.node(1));
    }
  }
}
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
void EdgeUniqueIdBuilder::
_computeEdgesUniqueIdsSequential()
{
  bool is_verbose = m_mesh_builder->isVerbose();
  Integer nb_cell = m_mesh_builder->oneMeshItemAdder()->nbCell();
 
  ItemInternalMap& cells_map = m_mesh->cellsMap();
 
  // In sequential mode, the uniqueId() of the cells cannot exceed
  // the size of Integers even in 32 bits.
  Int32 max_uid = 0;
  cells_map.eachItem([&](Item cell) {
    Int32 cell_uid = cell.uniqueId().asInt32();
    if (cell_uid > max_uid)
      max_uid = cell_uid;
  });
  info() << "Max uid=" << max_uid;
  Int32UniqueArray cell_first_edge_uid(max_uid + 1);
  Int32UniqueArray cell_nb_num_back_edge(max_uid + 1);
  Int32UniqueArray cell_true_boundary_edge(max_uid + 1);
 
  cells_map.eachItem([&](Cell cell) {
    Int32 cell_uid = cell.uniqueId().asInt32();
    Integer nb_num_back_edge = 0;
    Integer nb_true_boundary_edge = 0;
    for (Edge edge : cell.edges()) {
      if (edge.itemBase().backCell() == cell)
        ++nb_num_back_edge;
      else if (edge.nbCell() == 1) {
        ++nb_true_boundary_edge;
      }
    }
    cell_nb_num_back_edge[cell_uid] = nb_num_back_edge;
    cell_true_boundary_edge[cell_uid] = nb_true_boundary_edge;
  });
 
  Integer current_edge_uid = 0;
  for (Integer i = 0; i < nb_cell; ++i) {
    cell_first_edge_uid[i] = current_edge_uid;
    current_edge_uid += cell_nb_num_back_edge[i] + cell_true_boundary_edge[i];
  }
 
  if (is_verbose) {
    for (Integer i = 0; i < nb_cell; ++i) {
      info() << "Recv: Cell EdgeInfo celluid=" << i
             << " firstedgeuid=" << cell_first_edge_uid[i]
             << " nbback=" << cell_nb_num_back_edge[i]
             << " nbbound=" << cell_true_boundary_edge[i];
    }
  }
 
  cells_map.eachItem([&](Cell cell) {
    Int32 cell_uid = cell.uniqueId().asInt32();
    Integer nb_num_back_edge = 0;
    Integer nb_true_boundary_edge = 0;
    for (Edge edge : cell.edges()) {
      Int64 edge_new_uid = NULL_ITEM_UNIQUE_ID;
      //info() << "CHECK CELLUID=" << cell_uid << " EDGELID=" << edge->localId();
      if (edge.itemBase().backCell() == cell) {
        edge_new_uid = cell_first_edge_uid[cell_uid] + nb_num_back_edge;
        ++nb_num_back_edge;
      }
      else if (edge.nbCell() == 1) {
        edge_new_uid = cell_first_edge_uid[cell_uid] + cell_nb_num_back_edge[cell_uid] + nb_true_boundary_edge;
        ++nb_true_boundary_edge;
      }
      if (edge_new_uid != NULL_ITEM_UNIQUE_ID) {
        //info() << "NEW EDGE UID: LID=" << edge->localId() << " OLDUID=" << edge->uniqueId()
        //<< " NEWUID=" << edge_new_uid << " THIS=" << edge;
        edge.mutableItemBase().setUniqueId(edge_new_uid);
      }
    }
  });
 
  if (is_verbose) {
    OStringStream ostr;
    cells_map.eachItem([&](Cell cell) {
      Int32 cell_uid = cell.uniqueId().asInt32();
      Integer index = 0;
      for (Edge edge : cell.edges()) {
        Int64 opposite_cell_uid = NULL_ITEM_UNIQUE_ID;
        bool true_boundary = false;
        bool internal_other = false;
        if (edge.itemBase().backCell() == cell) {
        }
        else if (edge.nbCell() == 1) {
          true_boundary = true;
        }
        else {
          internal_other = true;
          opposite_cell_uid = edge.itemBase().backCell().uniqueId().asInt64();
        }
        ostr() << "NEW LOCAL ID FOR CELLEDGE " << cell_uid << ' '
               << index << ' ' << edge.uniqueId() << " (";
        for (Node node : edge.nodes()) {
          ostr() << ' ' << node.uniqueId();
        }
        ostr() << ")";
        if (internal_other)
          ostr() << " internal-other";
        if (true_boundary)
          ostr() << " true-boundary";
        if (opposite_cell_uid != NULL_ITEM_ID)
          ostr() << " opposite " << opposite_cell_uid;
        ostr() << '\n';
        ++index;
      }
    });
    info() << ostr.str();
  }
}
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
void EdgeUniqueIdBuilder::
_computeEdgesUniqueIdsParallelV2()
{
  // Positions the uniqueId() of the edges very simply.
  // If the maximum uniqueId() of the nodes is MAX_NODE_UID, then
  // the uniqueId() of an edge is:
  //
  // node(0).uniqueId() * MAX_NODE_UID + node(1).uniqueId()
  //
  // This only works if MAX_NODE_UID is less than 2^31.
 
  IParallelMng* pm = m_mesh->parallelMng();
 
  ItemInternalMap& nodes_map = m_mesh->nodesMap();
  ItemInternalMap& edges_map = m_mesh->edgesMap();
 
  Int64 max_uid = 0;
  nodes_map.eachItem([&](Item node) {
    if (node.uniqueId() > max_uid)
      max_uid = node.uniqueId();
  });
  Int64 total_max_uid = pm->reduce(Parallel::ReduceMax, max_uid);
  if (total_max_uid > INT32_MAX)
    ARCANE_FATAL("Max uniqueId() for node is too big v={0} max_allowed={1}", total_max_uid, INT32_MAX);
 
  edges_map.eachItem([&](Edge edge) {
    Node node0{ edge.node(0) };
    Node node1{ edge.node(1) };
    Int64 new_uid = (node0.uniqueId().asInt64() * total_max_uid) + node1.uniqueId().asInt64();
    edge.mutableItemBase().setUniqueId(new_uid);
  });
}
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
void EdgeUniqueIdBuilder::
_computeEdgesUniqueIdsParallel3()
{
  IParallelMng* pm = m_mesh->parallelMng();
  ItemInternalMap& nodes_map = m_mesh->nodesMap();
 
  // Determines the maximum uniqueId() of the nodes
  Int64 my_max_node_uid = NULL_ITEM_UNIQUE_ID;
  nodes_map.eachItem([&](Item item) {
    Int64 node_uid = item.uniqueId();
    if (node_uid > my_max_node_uid)
      my_max_node_uid = node_uid;
  });
  Int64 global_max_node_uid = pm->reduce(Parallel::ReduceMax, my_max_node_uid);
  debug() << "NODE_UID_INFO: MY_MAX_UID=" << my_max_node_uid
          << " GLOBAL=" << global_max_node_uid;
 
  Parallel3EdgeUniqueIdBuilder builder(traceMng(), m_mesh_builder, global_max_node_uid);
  builder.compute();
}
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
void EdgeUniqueIdBuilder::
_computeEdgesUniqueIdsParallel64bit()
{
  // Positions the uniqueId() of the edges
  // using a hash of the two nodes of the edge.
  ItemInternalMap& edges_map = m_mesh->edgesMap();
 
  std::hash<Int64> hasher;
 
  edges_map.eachItem([&](Edge edge) {
    Node node0{ edge.node(0) };
    Node node1{ edge.node(1) };
    size_t hash0 = hasher(node0.uniqueId().asInt64());
    size_t hash1 = hasher(node1.uniqueId().asInt64());
    hash0 ^= hash1 + 0x9e3779b9 + (hash0 << 6) + (hash0 >> 2);
    Int64 new_uid = hash0 & 0x7fffffff;
    edge.mutableItemBase().setUniqueId(new_uid);
  });
}
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
} // End namespace Arcane::mesh
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/