ext/OGDF/src/layered/SplitHeuristic.cpp

   1 /*
   2  * $Revision: 2552 $
   3  *
   4  * last checkin:
   5  *   $Author: gutwenger $
   6  *   $Date: 2012-07-05 16:45:20 +0200 (Do, 05. Jul 2012) $
   7  ***************************************************************/
   8
   9 /** \file
  10  * \brief Implementation of split heuristic.
  11  *
  12  * \author Andrea Wagner
  13  *
  14  * \par License:
  15  * This file is part of the Open Graph Drawing Framework (OGDF).
  16  *
  17  * \par
  18  * Copyright (C)<br>
  19  * See README.txt in the root directory of the OGDF installation for details.
  20  *
  21  * \par
  22  * This program is free software; you can redistribute it and/or
  23  * modify it under the terms of the GNU General Public License
  24  * Version 2 or 3 as published by the Free Software Foundation;
  25  * see the file LICENSE.txt included in the packaging of this file
  26  * for details.
  27  *
  28  * \par
  29  * This program is distributed in the hope that it will be useful,
  30  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  31  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  32  * GNU General Public License for more details.
  33  *
  34  * \par
  35  * You should have received a copy of the GNU General Public
  36  * License along with this program; if not, write to the Free
  37  * Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  38  * Boston, MA 02110-1301, USA.
  39  *
  40  * \see  http://www.gnu.org/copyleft/gpl.html
  41  ***************************************************************/
  42
  43
  44 #include <ogdf/layered/SplitHeuristic.h>
  45 #include <ogdf/layered/CrossingsMatrix.h>
  46
  47 namespace ogdf
  48 {
  49 //-------------------------------------------------------------------
  50 //                          SplitHeuristic
  51 //-------------------------------------------------------------------
  52
  53 void SplitHeuristic::init (const Hierarchy &H)
  54 {
  55         m_cm = new CrossingsMatrix(H);
  56 }
  57
  58 void SplitHeuristic::cleanup()
  59 {
  60         delete m_cm;
  61 }
  62
  63 // ordinary call
  64 void SplitHeuristic::call(Level &L)
  65 {
  66         m_cm->init(L);
  67         buffer = Array<node>(L.size());
  68
  69         recCall(L, 0, L.size() - 1);
  70
  71         buffer = Array<node>(-1);
  72 }
  73
  74 // SimDraw call
  75 void SplitHeuristic::call(Level &L, const EdgeArray<unsigned int> *edgeSubGraph)
  76 {
  77         // only difference to call is the different calculation of the crossingsmatrix
  78         m_cm->init(L, edgeSubGraph);
  79         buffer = Array<node>(L.size());
  80
  81         recCall(L, 0, L.size() - 1);
  82
  83         buffer = Array<node>(-1);
  84 }
  85
  86 void SplitHeuristic::recCall(Level &L, int low, int high)
  87 {
  88         if (high <= low) return;
  89
  90         const Hierarchy &H = L.hierarchy();
  91         CrossingsMatrix &crossings = *m_cm;
  92         int up = high, down = low;
  93
  94         // chooses L[low] as pivot
  95         int i;
  96         for (i = low+1; i <= high; i++)
  97         {
  98                 if (crossings(i,low) < crossings(low,i))
  99                         buffer[down++] = L[i];
 100         }
 101
 102         // use two for-loops in order to keep the number of swaps low
 103         for (i = high; i >= low+1; i--)
 104         {
 105                 if (crossings(i,low) >= crossings(low,i))
 106                         buffer[up--] = L[i];
 107         }
 108
 109         buffer[down] = L[low];
 110
 111         for (i = low; i < high; i++)
 112         {
 113                 int j = H.pos(buffer[i]);
 114                 if (i != j)
 115                 {
 116                         L.swap(i,j);
 117                         crossings.swap(i,j);
 118                 }
 119         }
 120
 121         recCall(L,low,down-1);
 122         recCall(L,up+1,high);
 123 }
 124
 125 } // end namespace ogdf