quadrialteral_util_impl.h

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/*
 * Copyright (c) 2016:  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__UG_quadrialteral_util_impl
#define __H__UG_quadrialteral_util_impl
 
#include <set>
#include "boost/iterator/transform_iterator.hpp"
#include "quadrilateral_util.h"
#include "lib_grid/algorithms/geom_obj_util/vertex_util.h"
#include "common/util/hash.h"
 
namespace ug{
 
template <class face_iter_t, class TAAPos>
void ReplaceByQuadrilaterals_FaceBased(
    Grid& g,
    face_iter_t facesBegin,
    face_iter_t facesEnd,
    TAAPos aaPos)
{
  std::vector<Edge*> edges;
  GetInnerEdgesOfFaceSoup(edges, g, facesBegin, facesEnd);
 
  if(!edges.empty())
  {
    ReplaceByQuadrilaterals_EdgeBased (
        g,
        edges.begin(),
        edges.end(),
        aaPos);
  }
}
 
namespace detail{
  namespace quadUtil{
    struct EdgeToQuadInfo {
      EdgeToQuadInfo () : e(NULL), quality(-1) {};
      EdgeToQuadInfo (Edge* _e, number _q) : e(_e), quality(_q) {};
 
      typedef Edge* result_type;
 
      Edge* e;
      number quality;
 
      bool operator < (const EdgeToQuadInfo& other) const
      {return quality > other.quality;}
 
      inline Edge* operator() (const EdgeToQuadInfo& v) const
      {return v.e;}
    };
  }// end of namespace
}// end of namespace detail
 
template <class edge_iter_t, class TAAPos>
void ReplaceByQuadrilaterals_EdgeBased(
    Grid& g,
    edge_iter_t edgesBegin,
    edge_iter_t edgesEnd,
    TAAPos aaPos)
{
  using namespace detail::quadUtil;
 
  Grid::face_traits::secure_container faces;
  FaceDescriptor fd(4);
  std::multiset<EdgeToQuadInfo> ms;
 
  for(edge_iter_t eiter = edgesBegin; eiter != edgesEnd; ++eiter){
    Edge* e = *eiter;
    g.associated_elements(faces, e);
    if(   faces.size() == 2
      &&  faces[0]->num_vertices() == 3
      && faces[1]->num_vertices() == 3)
    {
      int i0 = GetConnectedVertexIndex(faces[0], e);
      if(i0 != -1){
        fd.set_vertex(0, faces[0]->vertex(i0));
        fd.set_vertex(1, faces[0]->vertex((i0+1)%3));
        fd.set_vertex(2, GetConnectedVertex(e, faces[1]));
        fd.set_vertex(3, faces[0]->vertex((i0+2)%3));
 
        ms.insert(EdgeToQuadInfo(e, FaceQuality(&fd, aaPos)));
      }
    }
  }
 
  typedef boost::transform_iterator<
            EdgeToQuadInfo,
            std::multiset<EdgeToQuadInfo>::iterator>
      trans_iter_t;
 
  ReplaceByQuadrilaterals_EdgeBasedNoSort(
      g,
      trans_iter_t(ms.begin()),
      trans_iter_t(ms.end()));
}
 
 
template <class face_iter_t>
void ReplaceByQuadrilaterals_FaceBasedNoSort(
    Grid& g,
    face_iter_t facesBegin,
    face_iter_t facesEnd)
{
  std::vector<Edge*> edges;
  GetInnerEdgesOfFaceSoup(edges, g, facesBegin, facesEnd);
 
  if(!edges.empty())
  {
    ReplaceByQuadrilaterals_EdgeBasedNoSort (
        g,
        edges.begin(),
        edges.end());
  }
}
 
 
template <class edge_iter_t>
void ReplaceByQuadrilaterals_EdgeBasedNoSort(
    Grid& g,
    edge_iter_t edgesBegin,
    edge_iter_t edgesEnd)
{
  Grid::face_traits::secure_container faces;
  for(edge_iter_t eiter = edgesBegin; eiter != edgesEnd;)
  {
    Edge* e = *eiter;
    ++eiter;
    g.associated_elements(faces, e);
    if(faces.size() == 2) {
      try{
      //NOTE: This may fail. faces[0] and faces[1] don't have to be
      //    triangles or may be identical etc. This would, however,
      //    raise an UGError.
        ReplaceByQuadrilateral(g, faces[0], faces[1]);
      }
      catch(UGError&) {}
    }
  }
}
 
}// end of namespace
 
#endif  //__H__UG_quadrialteral_util_impl