CartesianFaceUniqueIdBuilder.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
//-----------------------------------------------------------------------------
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/* CartesianFaceUniqueIdBuilder.cc                             (C) 2000-2024 */
/*                                                                           */
/* Construction of unique face IDs in cartesian coordinates.                 */
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#include "arcane/mesh/DynamicMesh.h"
 
#include "arcane/core/ICartesianMeshGenerationInfo.h"
#include "arcane/core/IParallelMng.h"
#include "arcane/core/CartesianGridDimension.h"
 
#include "arcane/mesh/ItemInternalMap.h"
 
#include <array>
 
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namespace Arcane::mesh
{
 
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class CartesianFaceUniqueIdBuilder
: public TraceAccessor
{
 public:

  explicit CartesianFaceUniqueIdBuilder(DynamicMesh* mesh);
 
 public:
 
  void computeFacesUniqueIdAndOwner();
 
 private:
 
  DynamicMesh* m_mesh = nullptr;
  IParallelMng* m_parallel_mng = nullptr;
  bool m_is_verbose = false;
};
 
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CartesianFaceUniqueIdBuilder::
CartesianFaceUniqueIdBuilder(DynamicMesh* mesh)
: TraceAccessor(mesh->traceMng())
, m_mesh(mesh)
, m_parallel_mng(mesh->parallelMng())
{
}
 
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void CartesianFaceUniqueIdBuilder::
computeFacesUniqueIdAndOwner()
{
  auto* cmgi = ICartesianMeshGenerationInfo::getReference(m_mesh, false);
  if (!cmgi)
    ARCANE_FATAL("No 'ICartesianMeshGenerationInfo'. The mesh is not a cartesian mesh "
                 "or was not generated by 'CartesianMeshGenerator'");
 
  Integer dimension = m_mesh->dimension();
  if (dimension != 2 && dimension != 3)
    ARCANE_THROW(NotSupportedException, "Bad value '{0}' for dimension. Only dimensions 2 or 3 are supported",
                 dimension);
  Int32 my_rank = m_mesh->parallelMng()->commRank();
 
  Int64ConstArrayView global_nb_cells = cmgi->globalNbCells();
  info() << "Dim=" << dimension;
 
  CartesianGridDimension grid_dimension(global_nb_cells[0], global_nb_cells[1], global_nb_cells[2]);
  Int64x3 nb_cell = grid_dimension.nbCell();
  Int64x3 nb_face = grid_dimension.nbFace();
  Int64x3 nb_face_dir = grid_dimension.nbFaceParallelToDirection();
 
  Int64 nb_cell_xy = nb_cell.x * nb_cell.y;
 
  Int64 face_offset_z = nb_face_dir.x + nb_face_dir.y;
  Int64 nb_face_xyz = face_offset_z + nb_cell_xy;
  Int64 total_nb_face_xy = (nb_face_dir.x + nb_face_dir.y) * nb_cell.z;
  Int64 total_nb_face_x = (nb_face_dir.x * nb_cell.z);
 
  info() << "NB_Cell: X=" << nb_cell.x << " Y=" << nb_cell.y << " Z=" << nb_cell.z
         << " XY=" << nb_cell_xy;
  info() << "NB_Face: X=" << nb_face.x << " Y=" << nb_face.y << " Z=" << nb_face.z
         << " NbDirX=" << nb_face_dir.x << " NbDirY=" << nb_face_dir.y << " NbDirZ=" << nb_face_dir.z
         << " NbFaceXYZ=" << nb_face_xyz << " OffsetZ=" << face_offset_z
         << " TotalNbFaceX=" << total_nb_face_x << " TotalNbFaceXY=" << total_nb_face_xy;
 
  auto own_cells_offsets = cmgi->ownCellOffsets();
  Int64 own_cell_offset_x = own_cells_offsets[0];
  Int64 own_cell_offset_y = own_cells_offsets[1];
  Int64 own_cell_offset_z = own_cells_offsets[2];
  info() << "CellOffset: X=" << own_cell_offset_x << " Y=" << own_cell_offset_y << " Z=" << own_cell_offset_z;
 
  auto sub_domain_offsets = cmgi->subDomainOffsets();
  Int64 sub_domain_offset_x = sub_domain_offsets[0];
  Int64 sub_domain_offset_y = sub_domain_offsets[1];
  Int64 sub_domain_offset_z = sub_domain_offsets[2];
  info() << "SubDomainOffset: X=" << sub_domain_offset_x << " Y=" << sub_domain_offset_y << " Z=" << sub_domain_offset_z;
 
  auto nb_sub_domains = cmgi->nbSubDomains();
  Int32 nb_sub_domain_x = nb_sub_domains[0];
  Int32 nb_sub_domain_y = nb_sub_domains[1];
  Int32 nb_sub_domain_z = nb_sub_domains[2];
  info() << "NbSubDomain: X=" << nb_sub_domain_x << " Y=" << nb_sub_domain_y << " Z=" << nb_sub_domain_z;
 
  // Determines the lower rank in each direction
  Int32 previous_rank_x = my_rank;
  Int32 previous_rank_y = my_rank;
  Int32 previous_rank_z = my_rank;
 
  ItemInternalMap& cells_map = m_mesh->cellsMap();
  bool is_verbose = m_is_verbose;
 
  if (dimension == 2) {
    if (sub_domain_offset_x > 0)
      previous_rank_x = my_rank - 1;
    if (sub_domain_offset_y > 0)
      previous_rank_y = my_rank - nb_sub_domain_x;
    info() << "PreviousRank X=" << previous_rank_x << " Y=" << previous_rank_y;
    CartesianGridDimension::CellUniqueIdComputer2D cell_uid_computer(0, nb_cell.x);
    CartesianGridDimension::FaceUniqueIdComputer2D face_uid_computer(grid_dimension.getFaceComputer2D(0));
 
    // The cells are quadrangles
    std::array<Int64, 4> face_uids;
    std::array<Int64, 4> face_uids2;
    cells_map.eachItem([&](Cell cell) {
      // Retrieves the index (I,J) of the cell
      Int64 uid = cell.uniqueId();
      const Int64 y2 = uid / nb_cell.x;
      const Int64 x2 = uid % nb_cell.x;
      Int64x3 xyz = cell_uid_computer.compute(uid);
      Int64 x = xyz.x;
      Int64 y = xyz.y;
      // For test. To be removed later
      if (x != x2)
        ARCANE_FATAL("Bad X {0} {1}", x, x2);
      if (y != y2)
        ARCANE_FATAL("Bad Y {0} {1}", y, y2);
      if (is_verbose)
        info() << "CELL (UID=" << uid << ",XY=" << x << "," << y << ") "
               << " N0=" << cell.node(0).uniqueId()
               << " N1=" << cell.node(1).uniqueId()
               << " N2=" << cell.node(2).uniqueId()
               << " N3=" << cell.node(3).uniqueId();
      //  For test. To be removed later and keep the one from face_uid_computer.
      // Faces according to Y
      face_uids[0] = (x + 0) + ((y + 0) * nb_cell.x) + nb_face_dir.x;
      face_uids[2] = (x + 0) + ((y + 1) * nb_cell.x) + nb_face_dir.x;
 
      // Faces according to X
      face_uids[1] = (x + 1) + (y + 0) * nb_face.x;
      face_uids[3] = (x + 0) + (y + 0) * nb_face.x;
      face_uids2 = face_uid_computer.computeForCell(x, y);
      for (int i = 0; i < 4; ++i) {
        if (face_uids[i] != face_uids2[i])
          ARCANE_FATAL("Bad face uid i={0} ref={1} new={2}", i, face_uids[i], face_uids2[i]);
      }
      for (int i = 0; i < 4; ++i) {
        Face face = cell.face(i);
        if (is_verbose)
          info() << "CELL=" << uid << " Face=" << i << " uid=" << face_uids[i]
                 << " N0=" << face.node(0).uniqueId()
                 << " N1=" << face.node(1).uniqueId();
 
        face.mutableItemBase().setUniqueId(face_uids[i]);
      }
      // Positions the owner of the lower face in X
      if (x == own_cell_offset_x && previous_rank_x != my_rank)
        cell.face(3).mutableItemBase().setOwner(previous_rank_x, my_rank);
      // Positions the owner of the lower face in Y
      if (y == own_cell_offset_y && previous_rank_y != my_rank)
        cell.face(0).mutableItemBase().setOwner(previous_rank_y, my_rank);
    });
  }
  else if (dimension == 3) {
    if (sub_domain_offset_x > 0)
      previous_rank_x = my_rank - 1;
    if (sub_domain_offset_y > 0)
      previous_rank_y = my_rank - nb_sub_domain_x;
    if (sub_domain_offset_z > 0)
      previous_rank_z = my_rank - (nb_sub_domain_x * nb_sub_domain_y);
    info() << "PreviousRank X=" << previous_rank_x << " Y=" << previous_rank_y << " Z=" << previous_rank_z;
    CartesianGridDimension::CellUniqueIdComputer3D cell_uid_computer(0, nb_cell.x, nb_cell_xy);
    CartesianGridDimension::FaceUniqueIdComputer3D face_uid_computer(grid_dimension.getFaceComputer3D(0));
    // The cells are hexahedrons
    std::array<Int64, 6> face_uids;
    std::array<Int64, 6> face_uids2;
    cells_map.eachItem([&](Cell cell) {
      // Retrieves the index (I,J) of the cell
      Int64 uid = cell.uniqueId();
      Int64 z2 = uid / nb_cell_xy;
      Int64 v2 = uid - (z2 * nb_cell_xy);
      Int64 y2 = v2 / nb_cell.x;
      Int64 x2 = v2 % nb_cell.x;
      Int64x3 xyz = cell_uid_computer.compute(uid);
      Int64 x = xyz.x;
      Int64 y = xyz.y;
      Int64 z = xyz.z;
      // For test. To be removed later
      if (x != x2)
        ARCANE_FATAL("Bad X {0} {1}", x, x2);
      if (y != y2)
        ARCANE_FATAL("Bad Y {0} {1}", y, y2);
      if (z != z2)
        ARCANE_FATAL("Bad Z {0} {1}", z, z2);
      if (is_verbose)
        info() << "CELL (UID=" << uid << ",XYZ=" << x << "," << y << "," << z << ") "
               << " N0=" << cell.node(0).uniqueId()
               << " N1=" << cell.node(1).uniqueId()
               << " N2=" << cell.node(2).uniqueId()
               << " N3=" << cell.node(3).uniqueId()
               << " N4=" << cell.node(4).uniqueId()
               << " N5=" << cell.node(5).uniqueId()
               << " N6=" << cell.node(6).uniqueId()
               << " N7=" << cell.node(7).uniqueId();
 
      //  For test. To be removed later and keep the one from face_uid_computer.
      // Faces according to Z
      face_uids[0] = (x + 0) + ((y + 0) * nb_cell.x) + ((z + 0) * nb_face_dir.z) + total_nb_face_xy;
      face_uids[3] = (x + 0) + ((y + 0) * nb_cell.x) + ((z + 1) * nb_face_dir.z) + total_nb_face_xy;
 
      // Faces according to X
      face_uids[1] = (x + 0) + ((y + 0) * nb_face.x) + ((z + 0) * nb_face_dir.x);
      face_uids[4] = (x + 1) + ((y + 0) * nb_face.x) + ((z + 0) * nb_face_dir.x);
 
      // Faces according to Y
      face_uids[2] = (x + 0) + ((y + 0) * nb_cell.x) + ((z + 0) * nb_face_dir.y) + total_nb_face_x;
      face_uids[5] = (x + 0) + ((y + 1) * nb_cell.x) + ((z + 0) * nb_face_dir.y) + total_nb_face_x;
 
      face_uids2 = face_uid_computer.computeForCell(x, y, z);
      for (int i = 0; i < 6; ++i) {
        if (face_uids[i] != face_uids2[i])
          ARCANE_FATAL("Bad face uid i={0} ref={1} new={2}", i, face_uids[i], face_uids2[i]);
      }
 
      for (int i = 0; i < 6; ++i) {
        Face face = cell.face(i);
        if (is_verbose)
          info() << "CELL=" << uid << " Face=" << i << " uid=" << face_uids[i]
                 << " N0=" << face.node(0).uniqueId()
                 << " N1=" << face.node(1).uniqueId()
                 << " N2=" << face.node(2).uniqueId()
                 << " N3=" << face.node(3).uniqueId();
        face.mutableItemBase().setUniqueId(face_uids[i]);
      }
 
      // Positions the owner of the lower face in X
      if (x == own_cell_offset_x && previous_rank_x != my_rank)
        cell.face(1).mutableItemBase().setOwner(previous_rank_x, my_rank);
      // Positions the owner of the lower face in Y
      if (y == own_cell_offset_y && previous_rank_y != my_rank)
        cell.face(2).mutableItemBase().setOwner(previous_rank_y, my_rank);
      // Positions the owner of the lower face in Z
      if (z == own_cell_offset_z && previous_rank_z != my_rank)
        cell.face(0).mutableItemBase().setOwner(previous_rank_z, my_rank);
    });
  }
  else
    ARCANE_FATAL("Invalid dimension");
}
 
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extern "C++" void
arcaneComputeCartesianFaceUniqueId(DynamicMesh* mesh)
{
  CartesianFaceUniqueIdBuilder f(mesh);
  f.computeFacesUniqueIdAndOwner();
}
 
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} // End namespace Arcane::mesh
 
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