Free cookie consent management tool by TermsFeed Policy Generator

source: trunk/sources/HeuristicLab.Selection/3.3/LinearRankSelector.cs @ 2895

Last change on this file since 2895 was 2830, checked in by swagner, 15 years ago

Operator architecture refactoring (#95)

  • worked on operators and SGA
  • improved performance
File size: 3.0 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 System.Collections.Generic;
23using System.Linq;
24using HeuristicLab.Core;
25using HeuristicLab.Data;
26using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
27
28namespace HeuristicLab.Selection {
29  /// <summary>
30  /// A linear rank selection operator which considers the rank based on a single double quality value for selection.
31  /// </summary>
32  [Item("LinearRankSelector", "A linear rank selection operator which considers the rank based on a single double quality value for selection.")]
33  [EmptyStorableClass]
34  [Creatable("Test")]
35  public sealed class LinearRankSelector : StochasticSingleObjectiveSelector {
36    public LinearRankSelector()
37      : base() {
38      CopySelected.Value = true;
39    }
40
41    protected override IScope[] Select(List<IScope> scopes) {
42      int count = NumberOfSelectedSubScopesParameter.ActualValue.Value;
43      bool copy = CopySelectedParameter.Value.Value;
44      IRandom random = RandomParameter.ActualValue;
45      bool maximization = MaximizationParameter.ActualValue.Value;
46      ItemArray<DoubleData> qualities = QualityParameter.ActualValue;
47      IScope[] selected = new IScope[count];
48
49      // create a list for each scope that contains the scope's index in the original scope list and its lots
50      var temp = qualities.Select((x, index) => new { index, x.Value });
51      if (maximization)
52        temp = temp.OrderBy(x => x.Value);
53      else
54        temp = temp.OrderByDescending(x => x.Value);
55      var list = temp.Select((x, index) => new { x.index, lots = index + 1 }).ToList();
56
57      int lotSum = list.Count * (list.Count + 1) / 2;
58      for (int i = 0; i < count; i++) {
59        int selectedLot = random.Next(lotSum) + 1;
60        int index = 0;
61        int currentLot = list[index].lots;
62        while (currentLot < selectedLot) {
63          index++;
64          currentLot += list[index].lots;
65        }
66        if (copy)
67          selected[i] = (IScope)scopes[list[index].index].Clone();
68        else {
69          selected[i] = scopes[list[index].index];
70          scopes.RemoveAt(list[index].index);
71          lotSum -= list[index].lots;
72          list.RemoveAt(index);
73        }
74      }
75      return selected;
76    }
77  }
78}
Note: See TracBrowser for help on using the repository browser.