C++ MeshBase::elements_begin方法代码示例

void MeshTools::Subdivision::tag_boundary_ghosts(MeshBase & mesh)
{
  MeshBase::element_iterator       el     = mesh.elements_begin();
  const MeshBase::element_iterator end_el = mesh.elements_end();
  for (; el != end_el; ++el)
    {
      Elem * elem = *el;
      libmesh_assert_equal_to(elem->type(), TRI3SUBDIVISION);

      Tri3Subdivision * sd_elem = static_cast<Tri3Subdivision *>(elem);
      for (unsigned int i = 0; i < elem->n_sides(); ++i)
        {
          if (elem->neighbor(i) == libmesh_nullptr)
            {
              sd_elem->set_ghost(true);
              // set all other neighbors to ghosts as well
              if (elem->neighbor(next[i]))
                {
                  Tri3Subdivision * nb = static_cast<Tri3Subdivision *>(elem->neighbor(next[i]));
                  nb->set_ghost(true);
                }
              if (elem->neighbor(prev[i]))
                {
                  Tri3Subdivision * nb = static_cast<Tri3Subdivision *>(elem->neighbor(prev[i]));
                  nb->set_ghost(true);
                }
            }
        }
    }
}

void findElementsIntersectedByPlane(const Plane & plane, const MeshBase & mesh, std::vector<const Elem *> & intersected_elems)
{
  // Loop over all elements to find elements intersected by the plane
  MeshBase::const_element_iterator el = mesh.elements_begin();
  const MeshBase::const_element_iterator end_el = mesh.elements_end();
  for (; el != end_el; ++el)
  {
    const Elem * elem = *el;
    bool intersected = false;

    // Check whether the first node of this element is below or above the plane
    const Node node0 = *elem->get_node(0);
    bool node0_above_plane = plane.above_surface(node0);

    // Loop over the rest of the nodes and check if any node is on the other side of the plane
    for (unsigned int i = 1; i < elem->n_nodes(); ++i)
    {
      const Node node = *elem->get_node(i);

      bool node_above_plane = plane.above_surface(node);
      if (node0_above_plane != node_above_plane)
        intersected = true;
    }

    if (intersected)
      intersected_elems.push_back(elem);
  }
}

void TopologyMap::fill(const MeshBase& mesh)
{
  // Populate the nodes map
  MeshBase::const_element_iterator
    it = mesh.elements_begin(),
    end = mesh.elements_end();
  for (; it != end; ++it)
    {
      const Elem* elem = *it;

      // We only need to add nodes which might be added during mesh
      // refinement; this means they need to be child nodes.
      if (!elem->has_children())
        continue;

      for (unsigned int c = 0; c != elem->n_children(); ++c)
        {
          if (elem->child(c)->is_remote())
            continue;

          for (unsigned int n = 0; n != elem->n_nodes_in_child(c); ++n)
            {
              const std::vector<std::pair<dof_id_type, dof_id_type> >
                bracketing_nodes = elem->bracketing_nodes(c,n);

              this->add_node(*elem->child(c)->get_node(n),
                             bracketing_nodes);
            }
        }
    }
}

void UCDIO::write_interior_elems(std::ostream& out_stream, const MeshBase& mesh)
{
  std::string type[] =
    { "edge",  "edge",  "edge",
      "tri",   "tri",
      "quad",  "quad",  "quad",
      "tet",   "tet",
      "hex",   "hex",   "hex",
      "prism", "prism", "prism",
      "pyramid" };

  MeshBase::const_element_iterator it  = mesh.elements_begin();
  const MeshBase::const_element_iterator end = mesh.elements_end();

  unsigned int e=1; // 1-based element number for UCD

  // Write element information
  for (; it != end; ++it)
    {
      libmesh_assert (out_stream.good());

      // PB: I believe these are the only supported ElemTypes.
      const ElemType etype = (*it)->type();
      if( (etype != TRI3) && (etype != QUAD4) &&
          (etype != TET4) && (etype != HEX8) &&
          (etype != PRISM6) && (etype != PYRAMID5) )
        libmesh_error_msg("Error: Unsupported ElemType for UCDIO.");

      out_stream << e++ << " 0 " << type[etype] << "\t";
      // (*it)->write_ucd_connectivity(out_stream);
      (*it)->write_connectivity(out_stream, UCD);
    }

  return;
}

void CentroidPartitioner::_do_partition (MeshBase & mesh,
                                         const unsigned int n)
{
  this->partition_range(mesh,
                        mesh.elements_begin(),
                        mesh.elements_end(),
                        n);
}

void Partitioner::single_partition (MeshBase & mesh)
{
  LOG_SCOPE("single_partition()","Partitioner");

  // Loop over all the elements and assign them to processor 0.
  MeshBase::element_iterator       elem_it  = mesh.elements_begin();
  const MeshBase::element_iterator elem_end = mesh.elements_end();

  for ( ; elem_it != elem_end; ++elem_it)
    (*elem_it)->processor_id() = 0;

  // For a single partition, all the nodes are on processor 0
  MeshBase::node_iterator       node_it  = mesh.nodes_begin();
  const MeshBase::node_iterator node_end = mesh.nodes_end();

  for ( ; node_it != node_end; ++node_it)
    (*node_it)->processor_id() = 0;
}

void CentroidPartitioner::compute_centroids (MeshBase& mesh)
{
  _elem_centroids.clear();
  _elem_centroids.reserve(mesh.n_elem());

  //   elem_iterator it(mesh.elements_begin());
  //   const elem_iterator it_end(mesh.elements_end());

  MeshBase::element_iterator       it     = mesh.elements_begin();
  const MeshBase::element_iterator it_end = mesh.elements_end();

  for (; it != it_end; ++it)
    {
      Elem* elem = *it;

      _elem_centroids.push_back(std::make_pair(elem->centroid(), elem));
    }
}

void Partitioner::single_partition (MeshBase & mesh)
{
  this->single_partition_range(mesh.elements_begin(),
                               mesh.elements_end());
}