NewItemOwnerBuilder.h

// -*- 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
//-----------------------------------------------------------------------------
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/* NewItemOwnerBuilder.h                                       (C) 2000-2026 */
/*                                                                           */
/* Owner management tool for new items                                       */
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#ifndef ARCANE_MESH_NEWITEMOWNERBUILDER_H
#define ARCANE_MESH_NEWITEMOWNERBUILDER_H
 
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#include "arcane/mesh/MeshGlobal.h"
 
#include "arcane/core/Item.h"
 
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namespace Arcane::mesh
{
 
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// While waiting for an algorithm that better balances
// messages, we apply the following:
// - each sub-domain is responsible for determining the new
// owner of nodes, faces, edges, dual nodes, and links belonging to it.
// - for nodes and edges, the new owner is the new owner of the cell
// connected to this node whose uniqueId() is the smallest.
// - for faces, the new owner is the new owner of the cell behind this face
// if it is an internal face, and the connected mesh if it is a boundary face.
// - for dual nodes, the new owner is the new owner of the cell connected to
// the dual element
// - for links, the new owner is the new owner of the cell connected to the
// first dual node, that is, the owner of the link's first dual node.
 
class NewItemOwnerBuilder
{
 public:
 
  NewItemOwnerBuilder() {}
 
  // Determines the cell connected to the item
  template <typename T>
  inline Cell connectedCellOfItem(const T& item) const;
 
  // Determines the owner of the item, that is,
  // the owner of the cell connected to the item
  template <typename T>
  inline Integer ownerOfItem(const T& item) const
  {
    return connectedCellOfItem(item).owner();
  }
 
 private:
 
  // Finds the cell with the smallest uniqueId() of an item
  // Static polymorphism: only item types with a
  // cell() method are accepted
  template <typename T>
  inline Cell _minimumUniqueIdCellOfItem(const T& item) const
  {
    Cell cell = item.cell(0);
    for (Cell item_cell : item.cells()) {
      if (item_cell.uniqueId() < cell.uniqueId())
        cell = item_cell;
    }
    return cell;
  }
};
 
// For nodes, the connected cell is the one with the smallest uniqueId().
template <>
inline Cell NewItemOwnerBuilder::connectedCellOfItem<Node>(const Node& node) const
{
  return _minimumUniqueIdCellOfItem(node);
}
 
// For edges, the connected cell is the one with the smallest uniqueId().
template <>
inline Cell NewItemOwnerBuilder::connectedCellOfItem<Edge>(const Edge& edge) const
{
  return _minimumUniqueIdCellOfItem(edge);
}
 
// For faces, the connected cell is backCell() if it exists, otherwise frontCell()
template <>
inline Cell NewItemOwnerBuilder::connectedCellOfItem<Face>(const Face& face) const
{
  Cell cell = face.backCell();
  if (cell.null())
    cell = face.frontCell();
  return cell;
}
template <>
inline Cell NewItemOwnerBuilder::connectedCellOfItem<Particle>(const Particle& particle) const
{
  return particle.cell();
}
 
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} // namespace Arcane::mesh
 
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#endif