ext/OGDF/src/energybased/numexcept.h

   1 /*
   2  * $Revision: 2559 $
   3  *
   4  * last checkin:
   5  *   $Author: gutwenger $
   6  *   $Date: 2012-07-06 15:04:28 +0200 (Fr, 06. Jul 2012) $
   7  ***************************************************************/
   8
   9 /** \file
  10  * \brief Declaration of class numexcept (handling of numeric problems).
  11  *
  12  * \author Stefan Hachul
  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 #ifdef _MSC_VER
  45 #pragma once
  46 #endif
  47
  48 #ifndef OGDF_NUMEXCEPT_H
  49 #define OGDF_NUMEXCEPT_H
  50
  51 #include <ogdf/basic/geometry.h>
  52
  53 namespace ogdf {
  54
  55 //--------------------------------------------------------------------------
  56 // this class is developed for exceptions that might occure, when nodes are
  57 // placed at the same position and a new random position has to be found, or
  58 // when the calculated forces are near the machine accuracy, where no
  59 // reasonable numeric and logic calculations are possible any more
  60 //---------------------------------------------------------------------------
  61
  62         class numexcept
  63         {
  64         public:
  65
  66                 //Returns a distinct random point within the smallest disque D with center
  67                 //old_point that is contained in the box defined by xmin,...,ymax; The size of
  68                 //D is shrunk by multiplying with epsilon = 0.1; Precondition:
  69                 //old_point is contained in the box and the box is not equal to old_point.
  70                 DPoint choose_distinct_random_point_in_disque(
  71                         DPoint old_point,
  72                         double xmin,
  73                         double xmax,
  74                         double ymin,
  75                         double ymax);
  76
  77                 //A random point (distinct from old_pos) on the disque around old_pos with
  78                 //radius epsilon = 0.1 is computed.
  79                 DPoint choose_distinct_random_point_in_radius_epsilon(DPoint old_pos);
  80
  81                 //If distance has a value near the machine precision the repulsive force calculation
  82                 //is not possible (calculated values exceed the machine accuracy) in this cases
  83                 //true is returned and force is set to a reasonable value that does
  84                 //not cause problems; Else false is returned and force keeps unchanged.
  85                 bool f_rep_near_machine_precision(double distance, DPoint& force);
  86
  87                 //If distance has a value near the machine precision the (attractive)force
  88                 //calculation is not possible (calculated values exceed the machine accuracy) in
  89                 //this cases true is returned and force is set to a reasonable value that does
  90                 //not cause problems; Else false is returned and force keeps unchanged.
  91                 bool f_near_machine_precision(double distance, DPoint& force);
  92
  93                 //Returns true if a is "nearly" equal to b (needed, when machine accuracy is
  94                 //insufficient in functions well_seperated and bordering of NMM)
  95                 bool nearly_equal(double a, double b);
  96
  97         };
  98
  99 }//namespace ogdf
 100 #endif
 101