ext/OGDF/ogdf/graphalg/PageRank.h

   1 /*
   2  * $Revision: 2597 $
   3  *
   4  * last checkin:
   5  *   $Author: gutwenger $
   6  *   $Date: 2012-07-15 19:26:11 +0200 (So, 15. Jul 2012) $
   7  ***************************************************************/
   8
   9 /** \file
  10  * \brief Declaration of basic page rank.
  11  *
  12  * \author Martin Gronemann
  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 #ifndef OGDF_PAGE_RANK_H_
  44 #define OGDF_PAGE_RANK_H_
  45
  46 #include <ogdf/basic/NodeArray.h>
  47 #include <ogdf/basic/EdgeArray.h>
  48
  49 namespace ogdf {
  50
  51 //! Basic page rank calculation
  52 class BasicPageRank
  53 {
  54 public:
  55         BasicPageRank()
  56         {
  57                 initDefaultOptions();
  58         }
  59
  60         //! main algorithm call
  61         void call(
  62                 const Graph& graph,
  63                 const EdgeArray<double>& edgeWeight,
  64                 NodeArray<double>& pageRankResult);
  65
  66         //! sets the default options.
  67         void initDefaultOptions()
  68         {
  69                 m_dampingFactor         = 0.85;
  70                 m_maxNumIterations      = 1000;
  71                 m_threshold                     = 0.0;
  72         }
  73
  74         //! returns the damping factor for each iteration (default is 0.85)
  75         double dampingFactor() const
  76         {
  77                 return m_dampingFactor;
  78         }
  79
  80         //! sets the damping factor for each iteration (default is 0.85)
  81         void setDampingFactor(double dampingFactor)
  82         {
  83                 m_dampingFactor = dampingFactor;
  84         }
  85
  86         //! the maximum number of iterations (default is 1000)
  87         int maxNumIterations() const
  88         {
  89                 return m_maxNumIterations;
  90         }
  91
  92         //! sets the maximum number of iterations (default is 1000)
  93         void setMaxNumIterations(int maxNumIterations)
  94         {
  95                 m_maxNumIterations = maxNumIterations;
  96         }
  97
  98         /*! returns the threshold/epsilon. After each iteration the result is compared to
  99          * to the old one and in case all changes are smaller than threshold the algorithm
 100          * stops. Note that the default value is 0.0 resulting in maxNumIterations usually.
 101          */
 102         double threshold() const
 103         {
 104                 return m_threshold;
 105         }
 106
 107
 108         //! sets the threshold to t. See threshold for more information
 109         void setThreshold(double t)
 110         {
 111                 m_threshold = t;
 112         }
 113
 114 private:
 115         //! the damping factor
 116         double m_dampingFactor;
 117
 118         //! maximum number of iterations
 119         int m_maxNumIterations;
 120
 121         //! the threshold
 122         double m_threshold;
 123 };
 124
 125 } // end of namespace ogdf
 126
 127 #endif // OGDF_PAGE_RANK_H_
 128