dual_graph.h

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/*
 * Copyright (c) 2010-2015:  G-CSC, Goethe University Frankfurt
 * Author: Sebastian Reiter
 * 
 * This file is part of UG4.
 * 
 * UG4 is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License version 3 (as published by the
 * Free Software Foundation) with the following additional attribution
 * requirements (according to LGPL/GPL v3 §7):
 * 
 * (1) The following notice must be displayed in the Appropriate Legal Notices
 * of covered and combined works: "Based on UG4 (www.ug4.org/license)".
 * 
 * (2) The following notice must be displayed at a prominent place in the
 * terminal output of covered works: "Based on UG4 (www.ug4.org/license)".
 * 
 * (3) The following bibliography is recommended for citation and must be
 * preserved in all covered files:
 * "Reiter, S., Vogel, A., Heppner, I., Rupp, M., and Wittum, G. A massively
 *   parallel geometric multigrid solver on hierarchically distributed grids.
 *   Computing and visualization in science 16, 4 (2013), 151-164"
 * "Vogel, A., Reiter, S., Rupp, M., Nägel, A., and Wittum, G. UG4 -- a novel
 *   flexible software system for simulating pde based models on high performance
 *   computers. Computing and visualization in science 16, 4 (2013), 165-179"
 * 
 * This program 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.
 */
 
#ifndef __H__LIB_GRID__DUAL_GRAPH__
#define __H__LIB_GRID__DUAL_GRAPH__
 
#include <vector>
#include "lib_grid/lg_base.h"
 
namespace ug
{
 
 
template <class TGeomBaseObj, class TIndexType>
void ConstructDualGraph(std::vector<TIndexType>& adjacencyMapStructureOut,
            std::vector<TIndexType>& adjacencyMapOut,
            Grid& grid, Attachment<TIndexType>* paIndex = NULL,
            TGeomBaseObj** pGeomObjsOut = NULL,
            NeighborhoodType nbhType = NHT_DEFAULT,
            const GridObjectCollection* pgoc = NULL)
{
  using namespace std;
  typedef TGeomBaseObj Elem;
  typedef typename geometry_traits<Elem>::iterator ElemIterator;
  
//  set up index attachment and attachment accessor
  typedef Attachment<TIndexType> AIndex;
  AIndex aIndex;
  if(paIndex)
    aIndex = *paIndex;
  
  if(!grid.has_attachment<Elem>(aIndex))
    grid.attach_to_dv<Elem>(aIndex, -1);
    
  Grid::AttachmentAccessor<Elem, AIndex> aaInd(grid, aIndex);
  
  GridObjectCollection goc;
  if(pgoc)
    goc = *pgoc;
  else
    goc = grid.get_grid_objects();
 
//  init the indices
  TIndexType ind = 0;
  for(size_t lvl = 0; lvl < goc.num_levels(); ++lvl)
  {
    for(ElemIterator iter = goc.begin<Elem>(lvl); iter != goc.end<Elem>(lvl);
      ++iter, ++ind)
    {
      aaInd[*iter] = ind;
    }
  }
  
//  init the adjacencyMapStructure
  adjacencyMapStructureOut.resize(goc.num<Elem>() + 1);
  adjacencyMapOut.clear();
 
//  construct the graph
  {
    vector<Elem*> vNeighbours;
    int ind = 0;
 
  //  iterate through all elements
    for(size_t lvl = 0; lvl < goc.num_levels(); ++lvl)
    {
      for(ElemIterator iter = goc.begin<Elem>(lvl);
        iter != goc.end<Elem>(lvl); ++iter, ++ind)
      {
      //  get all neighbours
        CollectNeighbors(vNeighbours, *iter, grid, nbhType);
 
      //  store first entry at which the connections will be written to the map
        adjacencyMapStructureOut[ind] = adjacencyMapOut.size();
 
      //  iterate over the neighbours and push adjacent indices to the adjacencyMap
        for(size_t i = 0; i < vNeighbours.size(); ++i)
          adjacencyMapOut.push_back(aaInd[vNeighbours[i]]);
      }
    }
  }
  
//  add the final element
  adjacencyMapStructureOut[adjacencyMapStructureOut.size() - 1] = adjacencyMapOut.size();
  
//  fill pGeomObjsOut
  if(pGeomObjsOut)
  {
    int ind = 0;
    for(size_t lvl = 0; lvl < goc.num_levels(); ++lvl){
      for(ElemIterator iter = goc.begin<Elem>(lvl);
        iter != goc.end<Elem>(lvl); ++iter, ++ind)
      {
        pGeomObjsOut[ind] = *iter;
      }
    }
  }
  
//  clean up
  if(!paIndex)
    grid.detach_from<Elem>(aIndex);
}           
 
 
 
template <class TGeomBaseObj, class TIndexType>
void ConstructDualGraphMG(std::vector<TIndexType>& adjacencyMapStructureOut,
            std::vector<TIndexType>& adjacencyMapOut,
            std::vector<TIndexType>* pEdgeWeightsOut,
            MultiGrid& mg, size_t baseLevel = 0,
            int hWeight = 1, int vWeight = 1,
            Attachment<TIndexType>* paIndex = NULL,
            TGeomBaseObj** pGeomObjsOut = NULL,
            NeighborhoodType nbhType = NHT_DEFAULT)
{
  using namespace std;
  typedef TGeomBaseObj Elem;
  typedef typename geometry_traits<Elem>::iterator ElemIterator;
 
//  set up index attachment and attachment accessor
  typedef Attachment<TIndexType> AIndex;
  AIndex aIndex;
  if(paIndex)
    aIndex = *paIndex;
 
  if(!mg.has_attachment<Elem>(aIndex))
    mg.attach_to<Elem>(aIndex);
 
  Grid::AttachmentAccessor<Elem, AIndex> aaInd(mg, aIndex);
 
//  init the indices
  TIndexType ind = 0;
  size_t numElems = 0;
  for(size_t lvl = baseLevel; lvl < mg.num_levels(); ++lvl)
  {
    numElems += mg.num<Elem>(lvl);
    for(ElemIterator iter = mg.begin<Elem>(lvl); iter != mg.end<Elem>(lvl);
      ++iter, ++ind)
    {
      aaInd[*iter] = ind;
    }
  }
 
//  init the adjacencyMapStructure
  adjacencyMapStructureOut.resize(numElems + 1);
  adjacencyMapOut.clear();
  if(pEdgeWeightsOut)
    pEdgeWeightsOut->clear();
 
//  construct the graph
  {
    vector<Elem*> vNeighbours;
    int ind = 0;
 
  //  iterate through all elements
    for(size_t lvl = baseLevel; lvl < mg.num_levels(); ++lvl)
    {
      for(ElemIterator iter = mg.begin<Elem>(lvl);
        iter != mg.end<Elem>(lvl); ++iter, ++ind)
      {
        Elem* elem = *iter;
 
      //  get all neighbours
        CollectNeighbors(vNeighbours, elem, mg, nbhType);
 
      //  store first entry at which the connections will be written to the map
        adjacencyMapStructureOut[ind] = adjacencyMapOut.size();
 
      //  iterate over the neighbours and push adjacent indices to the adjacencyMap
        for(size_t i = 0; i < vNeighbours.size(); ++i)
          adjacencyMapOut.push_back(aaInd[vNeighbours[i]]);
 
        if(pEdgeWeightsOut){
          for(size_t i = 0; i < vNeighbours.size(); ++i)
            pEdgeWeightsOut->push_back(hWeight);
        }
 
      //  add a connection to the parents to the list
        GridObject* parent = mg.get_parent(elem);
        if(parent && Elem::type_match(parent)){
          adjacencyMapOut.push_back(aaInd[static_cast<Elem*>(parent)]);
          if(pEdgeWeightsOut)
            pEdgeWeightsOut->push_back(vWeight);
        }
 
      //  add children to the list
      //todo: add edge-weights
        size_t numChildren = mg.num_children<Elem>(elem);
        for(size_t i = 0; i < numChildren; ++i){
          adjacencyMapOut.push_back(aaInd[mg.get_child<Elem>(elem, i)]);
        }
 
        if(pEdgeWeightsOut){
          for(size_t i = 0; i < numChildren; ++i)
            pEdgeWeightsOut->push_back(1);
        }
      }
    }
  }
 
//  add the final element
  adjacencyMapStructureOut[adjacencyMapStructureOut.size() - 1] = adjacencyMapOut.size();
 
//  fill pGeomObjsOut
  if(pGeomObjsOut)
  {
    int ind = 0;
    for(size_t lvl = baseLevel; lvl < mg.num_levels(); ++lvl){
      for(ElemIterator iter = mg.begin<Elem>(lvl);
        iter != mg.end<Elem>(lvl); ++iter, ++ind)
      {
        pGeomObjsOut[ind] = *iter;
      }
    }
  }
 
//  clean up
  if(!paIndex)
    mg.detach_from<Elem>(aIndex);
}
 
 
template <typename TBaseElem>
class DualGraphNeighborCollector
{
  public:
    virtual ~DualGraphNeighborCollector() {}
    virtual void collect_neighbors(std::vector<TBaseElem*>& neighborsOut, TBaseElem* elem) = 0;
};
 
 
template <class TGeomBaseObj, class TIndexType>
void ConstructDualGraphMGLevel(
    std::vector<TIndexType>& adjacencyMapStructureOut,
    std::vector<TIndexType>& adjacencyMapOut,
    MultiGrid& mg, size_t level,
    Attachment<TIndexType>* paIndex = NULL,
    TGeomBaseObj** pGeomObjsOut = NULL,
    NeighborhoodType nbhType = NHT_DEFAULT,
    DualGraphNeighborCollector<TGeomBaseObj>* neighborCollector = NULL)
{
  using namespace std;
  typedef TGeomBaseObj Elem;
  typedef typename geometry_traits<Elem>::iterator ElemIterator;
 
//  set up index attachment and attachment accessor
  typedef Attachment<TIndexType> AIndex;
  AIndex aIndex;
  if(paIndex)
    aIndex = *paIndex;
 
  if(!mg.has_attachment<Elem>(aIndex))
    mg.attach_to<Elem>(aIndex);
 
  Grid::AttachmentAccessor<Elem, AIndex> aaInd(mg, aIndex);
 
//  init the indices
  size_t numElems = mg.num<Elem>(level);
  {
    TIndexType ind = 0;
    for(ElemIterator iter = mg.begin<Elem>(level); iter != mg.end<Elem>(level);
      ++iter, ++ind)
    {
      aaInd[*iter] = ind;
    }
  }
 
//  init the adjacencyMapStructure
  adjacencyMapStructureOut.resize(numElems + 1);
  adjacencyMapOut.clear();
 
//  construct the graph
  vector<Elem*> vNeighbours;
  int ind = 0;
 
//  generate adjacency structure first
  for(ElemIterator iter = mg.begin<Elem>(level);
    iter != mg.end<Elem>(level); ++iter, ++ind)
  {
    Elem* elem = *iter;
 
  //  get all neighbours
    if (neighborCollector)
      neighborCollector->collect_neighbors(vNeighbours, elem);
    else
      CollectNeighbors(vNeighbours, elem, mg, nbhType);
 
  //  store first entry at which the connections will be written to the map
    adjacencyMapStructureOut[ind] = adjacencyMapOut.size();
 
  //  iterate over the neighbours and push adjacent indices to the adjacencyMap
    for(size_t i = 0; i < vNeighbours.size(); ++i)
      adjacencyMapOut.push_back(aaInd[vNeighbours[i]]);
  }
 
//  add the final element
  adjacencyMapStructureOut[adjacencyMapStructureOut.size() - 1] = adjacencyMapOut.size();
 
//  fill pGeomObjsOut
  if(pGeomObjsOut)
  {
    int ind = 0;
    for(ElemIterator iter = mg.begin<Elem>(level);
      iter != mg.end<Elem>(level); ++iter, ++ind)
    {
      pGeomObjsOut[ind] = *iter;
    }
  }
 
//  clean up
  if(!paIndex)
    mg.detach_from<Elem>(aIndex);
}
 
 
}// end of namespace
 
#endif