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source: branches/Persistence Test/HeuristicLab.Permutation/3.2/RandomPermutationGenerator.cs @ 3154

Last change on this file since 3154 was 1530, checked in by gkronber, 16 years ago

Moved source files of plugins Hive ... Visualization.Test into version-specific sub-folders. #576

File size: 3.3 KB
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1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2008 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 System;
23using System.Collections.Generic;
24using System.Text;
25using HeuristicLab.Core;
26using HeuristicLab.Data;
27
28namespace HeuristicLab.Permutation {
29  /// <summary>
30  /// Generates a randomly shuffled permuation.
31  /// </summary>
32  public class RandomPermutationGenerator : OperatorBase {
33    /// <inheritdoc select="summary"/>
34    public override string Description {
35      get { return @"TODO\r\nOperator description still missing ..."; }
36    }
37
38    /// <summary>
39    /// Initializes a new instance of <see cref="RandomPermutationGenerator"/> with three variable infos
40    /// (<c>Length</c>, <c>Random</c> and <c>Permutation</c>).
41    /// </summary>
42    public RandomPermutationGenerator()
43      : base() {
44      AddVariableInfo(new VariableInfo("Length", "Permutation length", typeof(IntData), VariableKind.In));
45      AddVariableInfo(new VariableInfo("Random", "Pseudo random number generator", typeof(IRandom), VariableKind.In));
46      AddVariableInfo(new VariableInfo("Permutation", "Created random permutation", typeof(Permutation), VariableKind.New));
47    }
48
49    /// <summary>
50    /// Generates a randomly shuffled permutation.
51    /// </summary>
52    /// <param name="random">The random number generator.</param>
53    /// <param name="length">The length of the permutation to create.</param>
54    /// <returns>The generated permuation as int array.</returns>
55    public static int[] Apply(IRandom random, int length) {
56      int[] perm = new int[length];
57
58      for (int i = 0; i < length; i++)
59        perm[i] = i;
60
61      // Knuth shuffle
62      int index, tmp;
63      for (int i = 0; i < length - 1; i++) {
64        index = random.Next(i, length);
65        tmp = perm[i];
66        perm[i] = perm[index];
67        perm[index] = tmp;
68      }
69      return perm;
70    }
71
72    /// <summary>
73    /// Generates a randomly shuffled permutation.
74    /// </summary>
75    /// <remarks>Calls <see cref="Apply(HeuristicLab.Core.IRandom, int)"/>.</remarks>
76    /// <param name="scope">The current scope with the variables.</param>
77    /// <returns><c>null</c>.</returns>
78    public override IOperation Apply(IScope scope) {
79      IRandom random = GetVariableValue<IRandom>("Random", scope, true);
80      IntData length = GetVariableValue<IntData>("Length", scope, true);
81
82      int[] perm = Apply(random, length.Data);
83      scope.AddVariable(new Variable(scope.TranslateName("Permutation"), new Permutation(perm)));
84
85      return null;
86    }
87  }
88}
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