source: trunk/sources/HeuristicLab.Selection/3.3/TournamentSelector.cs @ 7259

Last change on this file since 7259 was 7259, checked in by swagner, 11 years ago

Updated year of copyrights to 2012 (#1716)

File size: 3.3 KB
Line 
1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2012 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.Collections.Generic;
23using System.Linq;
24using HeuristicLab.Common;
25using HeuristicLab.Core;
26using HeuristicLab.Data;
27using HeuristicLab.Optimization;
28using HeuristicLab.Parameters;
29using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
30
31namespace HeuristicLab.Selection {
32  /// <summary>
33  /// A tournament selection operator which considers a single double quality value for selection.
34  /// </summary>
35  [Item("TournamentSelector", "A tournament selection operator which considers a single double quality value for selection.")]
36  [StorableClass]
37  public sealed class TournamentSelector : StochasticSingleObjectiveSelector, ISingleObjectiveSelector {
38    public ValueLookupParameter<IntValue> GroupSizeParameter {
39      get { return (ValueLookupParameter<IntValue>)Parameters["GroupSize"]; }
40    }
41
42    [StorableConstructor]
43    private TournamentSelector(bool deserializing) : base(deserializing) { }
44    private TournamentSelector(TournamentSelector original, Cloner cloner) : base(original, cloner) { }
45    public override IDeepCloneable Clone(Cloner cloner) {
46      return new TournamentSelector(this, cloner);
47    }
48
49    public TournamentSelector()
50      : base() {
51      Parameters.Add(new ValueLookupParameter<IntValue>("GroupSize", "The size of the tournament group.", new IntValue(2)));
52    }
53
54    protected override IScope[] Select(List<IScope> scopes) {
55      int count = NumberOfSelectedSubScopesParameter.ActualValue.Value;
56      bool copy = CopySelectedParameter.Value.Value;
57      IRandom random = RandomParameter.ActualValue;
58      bool maximization = MaximizationParameter.ActualValue.Value;
59      List<double> qualities = QualityParameter.ActualValue.Select(x => x.Value).ToList();
60      int groupSize = GroupSizeParameter.ActualValue.Value;
61      IScope[] selected = new IScope[count];
62
63      for (int i = 0; i < count; i++) {
64        int best = random.Next(scopes.Count);
65        int index;
66        for (int j = 1; j < groupSize; j++) {
67          index = random.Next(scopes.Count);
68          if (((maximization) && (qualities[index] > qualities[best])) ||
69              ((!maximization) && (qualities[index] < qualities[best]))) {
70            best = index;
71          }
72        }
73
74        if (copy)
75          selected[i] = (IScope)scopes[best].Clone();
76        else {
77          selected[i] = scopes[best];
78          scopes.RemoveAt(best);
79          qualities.RemoveAt(best);
80        }
81      }
82      return selected;
83    }
84  }
85}
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