db/df9/arcanedoc_entities_snippet_cartesianmesh.html

// file_name is the name of the unstructured mesh file


Arcane::String file_name = options()->unstructuredMeshFile();

info() << "UnstructuredMeshFileName=" << file_name;


Arcane::ISubDomain* sd = subDomain();

Arcane::ICartesianMesh* cartesian_mesh = m_cartesian_mesh;

Arcane::IMesh* current_mesh = cartesian_mesh->mesh();

Arcane::IParallelMng* pm = current_mesh->parallelMng();


Arcane::MeshReaderMng reader_mng(sd);

Arcane::IMesh* new_mesh = reader_mng.readMesh("UnstructuredMesh2", file_name, pm);

info() << "MESH=" << new_mesh;


// Creation of the partitioning service

Arcane::ServiceBuilder<Arcane::IGridMeshPartitioner> sbuilder(sd);

auto partitioner_ref = sbuilder.createReference("SimpleGridMeshPartitioner", new_mesh);

Arcane::IGridMeshPartitioner* partitioner = partitioner_ref.get();


// Positions the coordinates of our subdomain in the grid

Int32 sd_x = cartesian_mesh->cellDirection(MD_DirX).subDomainOffset();

Int32 sd_y = cartesian_mesh->cellDirection(MD_DirY).subDomainOffset();

Int32 sd_z = cartesian_mesh->cellDirection(MD_DirZ).subDomainOffset();

partitioner->setPartIndex(sd_x, sd_y, sd_z);


// Positions the bounding box of our subdomain.

// To do this, iterate only over our nodes and take the min and max coordinates

Real max_value = FloatInfo<Real>::maxValue();

Real min_value = -max_value;

Arcane::Real3 min_box(max_value, max_value, max_value);

Arcane::Real3 max_box(min_value, min_value, min_value);

VariableNodeReal3& nodes_coord = current_mesh->nodesCoordinates();

ENUMERATE_ (Cell, icell, current_mesh->ownCells()) {

  Cell cell{ *icell };

  for (Node node : cell.nodes()) {

    Real3 coord = nodes_coord[node];

    min_box = math::min(min_box, coord);

    max_box = math::max(max_box, coord);

  }

}

partitioner->setBoundingBox(min_box, max_box);


// Applies the partitioning

partitioner->applyMeshPartitioning(new_mesh);