tree_node.h

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// The libMesh Finite Element Library.
// Copyright (C) 2002-2018 Benjamin S. Kirk, John W. Peterson, Roy H. Stogner

// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.

// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA



#ifndef LIBMESH_TREE_NODE_H
#define LIBMESH_TREE_NODE_H

// Local includes
#include "libmesh/libmesh_common.h"
#include "libmesh/bounding_box.h"
#include "libmesh/point.h"

// C++ includes
#include <cstddef>
#include <set>
#include <unordered_map>
#include <vector>

namespace libMesh
{

// Forward Declarations
class MeshBase;
class Node;
class Elem;

template <unsigned int N>
class TreeNode
{
public:
  TreeNode (const MeshBase & m,
            unsigned int tbs,
            const TreeNode<N> * p = nullptr);

  ~TreeNode ();

  bool is_root() const { return (parent == nullptr); }

  bool active() const { return children.empty(); }

  bool insert (const Node * nd);

  bool insert (const Elem * nd);

  void refine ();

  void set_bounding_box (const std::pair<Point, Point> & bbox);

  bool bounds_node (const Node * nd,
                    Real relative_tol = 0) const;

  bool bounds_point (const Point & p,
                     Real relative_tol = 0) const;

  unsigned int level () const;

  void print_nodes(std::ostream & out=libMesh::out) const;

  void print_elements(std::ostream & out=libMesh::out) const;

  void transform_nodes_to_elements (std::vector<std::vector<const Elem *>> & nodes_to_elem);

  void transform_nodes_to_elements (std::unordered_map<dof_id_type, std::vector<const Elem *>> & nodes_to_elem);

  unsigned int n_active_bins() const;

  const Elem * find_element (const Point & p,
                             const std::set<subdomain_id_type> * allowed_subdomains = nullptr,
                             Real relative_tol = TOLERANCE) const;


private:
  const Elem * find_element_in_children (const Point & p,
                                         const std::set<subdomain_id_type> * allowed_subdomains,
                                         Real relative_tol) const;

  BoundingBox create_bounding_box (unsigned int c) const;

  const MeshBase & mesh;

  const TreeNode<N> * parent;

  std::vector<TreeNode<N> * > children;

  BoundingBox bounding_box;

  std::vector<const Elem *> elements;

  std::vector<const Node *> nodes;

  const unsigned int tgt_bin_size;

  unsigned int target_bin_size_increase_level;

  bool contains_ifems;
};





// ------------------------------------------------------------
// TreeNode class inline methods
template <unsigned int N>
inline
TreeNode<N>::TreeNode (const MeshBase & m,
                       unsigned int tbs,
                       const TreeNode<N> * p) :
  mesh           (m),
  parent         (p),
  tgt_bin_size   (tbs),
  target_bin_size_increase_level(10),
  contains_ifems (false)
{
  // libmesh_assert our children are empty, thus we are active.
  libmesh_assert (children.empty());
  libmesh_assert (this->active());

  // Reserve space for the nodes & elements
  nodes.reserve    (tgt_bin_size);
  elements.reserve (tgt_bin_size);
}



template <unsigned int N>
inline
TreeNode<N>::~TreeNode ()
{
  // When we are destructed we must delete all of our
  // children.  They will this delete their children,
  // All the way down the line...
  for (std::size_t c=0; c<children.size(); c++)
    delete children[c];
}



template <unsigned int N>
inline
unsigned int TreeNode<N>::level () const
{
  if (parent != nullptr)
    return parent->level()+1;

  // if we have no parent, we are a level-0 box
  return 0;
}


} // namespace libMesh


#endif // LIBMESH_TREE_NODE_H