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source: trunk/sources/HeuristicLab.Permutation/3.3/InversionManipulator.cs @ 2865

Last change on this file since 2865 was 2854, checked in by svonolfe, 15 years ago

Ported ported permutation operators to HL 3.3 and added test cases (#889)

File size: 2.8 KB
Line 
1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2010 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
4 *
5 * This file is part of HeuristicLab.
6 *
7 * HeuristicLab is free software: you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation, either version 3 of the License, or
10 * (at your option) any later version.
11 *
12 * HeuristicLab is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
19 */
20#endregion
21
22using HeuristicLab.Core;
23using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
24
25namespace HeuristicLab.Permutation {
26  /// <summary>
27  /// An operator which inverts a randomly chosen part of a permutation.
28  /// </summary>
29  /// <remarks>
30  /// It is implemented as described in Eiben, A.E. and Smith, J.E. 2003. Introduction to Evolutionary Computation. Natural Computing Series, Springer-Verlag Berlin Heidelberg.<br />
31  /// </remarks>
32  [Item("InversionManipulator", "An operator which inverts a randomly chosen part of a permutation.")]
33  [EmptyStorableClass]
34  [Creatable("Test")]
35  public class InversionManipulator : PermutationManipulator {
36    /// <summary>
37    /// Inverts a randomly chosen part of a permutation.
38    /// </summary>
39    /// <param name="random">A random number generator.</param>
40    /// <param name="permutation">The permutation to manipulate.</param>
41    public static void Apply(IRandom random, Permutation permutation) {
42      int breakPoint1, breakPoint2;
43
44      breakPoint1 = random.Next(permutation.Length - 1);
45      do {
46        breakPoint2 = random.Next(permutation.Length - 1);
47      } while (breakPoint2 == breakPoint1);
48      if (breakPoint2 < breakPoint1) { int h = breakPoint1; breakPoint1 = breakPoint2; breakPoint2 = h; }
49
50      for (int i = 0; i <= (breakPoint2 - breakPoint1) / 2; i++) {  // invert permutation between breakpoints
51        int temp = permutation[breakPoint1 + i];
52        permutation[breakPoint1 + i] = permutation[breakPoint2 - i];
53        permutation[breakPoint2 - i] = temp;
54      }
55    }
56
57    /// <summary>
58    /// Inverts a randomly chosen part of a permutation.
59    /// </summary>
60    /// <param name="random">A random number generator.</param>
61    /// <param name="permutation">The permutation to manipulate.</param>
62    protected override void Manipulate(IRandom random, Permutation permutation) {
63      Apply(random, permutation);
64    }
65  }
66}
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