source: trunk/sources/HeuristicLab.Algorithms.TabuSearch/3.3/TabuSelector.cs @ 3140

Last change on this file since 3140 was 3140, checked in by abeham, 12 years ago

fixed tabu selector not finding copy selected #840

File size: 6.6 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;
23using System.Collections.Generic;
24using HeuristicLab.Core;
25using HeuristicLab.Data;
26using HeuristicLab.Operators;
27using HeuristicLab.Parameters;
28using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
29using HeuristicLab.Selection;
30
31namespace HeuristicLab.Algorithms.TabuSearch {
32  /// <summary>
33  /// The tabu selector is a selection operator that separates the best n moves that are either not tabu or satisfy the default aspiration criterion from the rest. It expects the move subscopes to be sorted.
34  /// </summary>
35  /// <remarks>
36  /// For different aspiration criteria a new operator should be implemented.
37  /// </remarks>
38  [Item("TabuSelector", "An operator that selects the best move that is either not tabu or satisfies the aspiration criterion. It expects the move subscopes to be sorted by the qualities of the moves (the best move is first).")]
39  [StorableClass]
40  public class TabuSelector : Selector {
41    /// <summary>
42    /// The best found quality so far.
43    /// </summary>
44    public LookupParameter<DoubleValue> BestQualityParameter {
45      get { return (LookupParameter<DoubleValue>)Parameters["BestQuality"]; }
46    }
47    /// <summary>
48    /// Whether to use the default aspiration criteria or not.
49    /// </summary>
50    public ValueLookupParameter<BoolValue> AspirationParameter {
51      get { return (ValueLookupParameter<BoolValue>)Parameters["Aspiration"]; }
52    }
53    /// <summary>
54    /// Whether the problem is a maximization problem or not.
55    /// </summary>
56    public IValueLookupParameter<BoolValue> MaximizationParameter {
57      get { return (IValueLookupParameter<BoolValue>)Parameters["Maximization"]; }
58    }
59    /// <summary>
60    /// The parameter for the move qualities.
61    /// </summary>
62    public ILookupParameter<ItemArray<DoubleValue>> MoveQualityParameter {
63      get { return (ILookupParameter<ItemArray<DoubleValue>>)Parameters["MoveQuality"]; }
64    }
65    /// <summary>
66    /// The parameter for the tabu status of the moves.
67    /// </summary>
68    public ILookupParameter<ItemArray<BoolValue>> MoveTabuParameter {
69      get { return (ILookupParameter<ItemArray<BoolValue>>)Parameters["MoveTabu"]; }
70    }
71    public IValueLookupParameter<BoolValue> CopySelectedParameter {
72      get { return (IValueLookupParameter<BoolValue>)Parameters["CopySelected"]; }
73    }
74
75    public BoolValue CopySelected {
76      get { return CopySelectedParameter.Value; }
77      set { CopySelectedParameter.Value = value; }
78    }
79
80    /// <summary>
81    /// Initializes a new intsance with 6 parameters (<c>Quality</c>, <c>BestQuality</c>,
82    /// <c>Aspiration</c>, <c>Maximization</c>, <c>MoveQuality</c>, and <c>MoveTabu</c>).
83    /// </summary>
84    public TabuSelector()
85      : base() {
86      Parameters.Add(new LookupParameter<DoubleValue>("BestQuality", "The best found quality so far."));
87      Parameters.Add(new ValueLookupParameter<BoolValue>("Aspiration", "Whether the default aspiration criterion should be used or not. The default aspiration criterion accepts a tabu move if it results in a better solution than the best solution found so far.", new BoolValue(true)));
88      Parameters.Add(new ValueLookupParameter<BoolValue>("Maximization", "Whether the problem is a maximization or minimization problem (used to decide whether a solution is better"));
89      Parameters.Add(new SubScopesLookupParameter<DoubleValue>("MoveQuality", "The quality of the move."));
90      Parameters.Add(new SubScopesLookupParameter<BoolValue>("MoveTabu", "The tabu status of the move."));
91      Parameters.Add(new ValueLookupParameter<BoolValue>("CopySelected", "True if the selected move should be copied.", new BoolValue(false)));
92    }
93
94    /// <summary>
95    /// Implements the tabu selection with the default aspiration criteria (choose a tabu move when it is better than the best so far).
96    /// </summary>
97    /// <exception cref="InvalidOperationException">Thrown when the neighborhood contained too little moves which are not tabu.</exception>
98    /// <param name="scopes">The scopes from which to select.</param>
99    /// <returns>The selected scopes.</returns>
100    protected override IScope[] Select(List<IScope> scopes) {
101      bool copy = CopySelectedParameter.Value.Value;
102      bool aspiration = AspirationParameter.ActualValue.Value;
103      bool maximization = MaximizationParameter.ActualValue.Value;
104      double bestQuality = BestQualityParameter.ActualValue.Value;
105      ItemArray<DoubleValue> moveQualities = MoveQualityParameter.ActualValue;
106      ItemArray<BoolValue> moveTabus = MoveTabuParameter.ActualValue;
107
108      IScope[] selected = new IScope[1];
109
110      // remember scopes that should be removed
111      List<int> scopesToRemove = new List<int>();
112      for (int i = 0; i < scopes.Count; i++) {
113        if (!moveTabus[i].Value
114          || aspiration && IsBetter(maximization, moveQualities[i].Value, bestQuality)) {
115          scopesToRemove.Add(i);
116          if (copy) selected[0] = (IScope)scopes[i].Clone();
117          else selected[0] = scopes[i];
118          break;
119        }
120      }
121
122      if (selected[0] == null) throw new InvalidOperationException("TabuSelector: The neighborhood contained no or too little moves that are not tabu.");
123
124      // remove from last to first so that the stored indices remain the same
125      if (!copy) {
126        while (scopesToRemove.Count > 0) {
127          scopes.RemoveAt(scopesToRemove[scopesToRemove.Count - 1]);
128          scopesToRemove.RemoveAt(scopesToRemove.Count - 1);
129        }
130      }
131
132      return selected;
133    }
134
135    private bool IsBetter(bool maximization, double moveQuality, double bestQuality) {
136      return (maximization && moveQuality > bestQuality || !maximization && moveQuality < bestQuality);
137    }
138  }
139}
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