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source: trunk/sources/HeuristicLab.Selection/3.3/NoSameMatesSelector.cs @ 5596

Last change on this file since 5596 was 5596, checked in by cfischer, 12 years ago

#1364 implemented NoSameMatesSelector

File size: 7.0 KB
Line 
1using System;
2using System.Collections.Generic;
3using System.Threading;
4using HeuristicLab.Common;
5using HeuristicLab.Core;
6using HeuristicLab.Data;
7using HeuristicLab.Optimization;
8using HeuristicLab.Parameters;
9using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
10
11namespace HeuristicLab.Selection {
12  /// <summary>
13  /// A selector which tries to select two parents which differ in quality.
14  /// </summary>
15  [Item("NoSameMatesSelector", "A selector which tries to select two parents which differ in quality.")]
16  [StorableClass]
17  public class NoSameMatesSelector : StochasticSingleObjectiveSelector, ISingleObjectiveSelector {
18    private const string SelectorParameterName = "Selector";
19    private const string QualityDifferencePercentageParameterName = "QualityDifferencePercentage";
20    private const string QualityDifferenceMaxAttemptsParameterName = "QualityDifferenceMaxAttempts";
21
22    #region Parameters
23    public IValueParameter<ISelector> SelectorParameter {
24      get { return (IValueParameter<ISelector>)Parameters[SelectorParameterName]; }
25    }
26    public IValueParameter<PercentValue> QualityDifferencePercentageParameter {
27      get { return (IValueParameter<PercentValue>)Parameters[QualityDifferencePercentageParameterName]; }
28    }
29    public IValueParameter<IntValue> QualityDifferenceMaxAttemptsParameter {
30      get { return (IValueParameter<IntValue>)Parameters[QualityDifferenceMaxAttemptsParameterName]; }
31    }
32    #endregion
33
34    #region Properties
35    public IntValue NumberOfSelectedSubScopes {
36      get { return NumberOfSelectedSubScopesParameter.ActualValue; }
37    }
38    public ISelector Selector {
39      get { return SelectorParameter.Value; }
40      set { SelectorParameter.Value = value; }
41    }
42    public PercentValue QualityDifferencePercentage {
43      get { return QualityDifferencePercentageParameter.Value; }
44    }
45    public IntValue QualityDifferenceMaxAttempts {
46      get { return QualityDifferenceMaxAttemptsParameter.Value; }
47    }
48    #endregion
49
50    [StorableConstructor]
51    protected NoSameMatesSelector(bool deserializing) : base(deserializing) { }
52    protected NoSameMatesSelector(NoSameMatesSelector original, Cloner cloner) : base(original, cloner) { }
53    public override IDeepCloneable Clone(Cloner cloner) {
54      return new NoSameMatesSelector(this, cloner);
55    }
56
57    public NoSameMatesSelector() : base() {
58      #region Create parameters
59      Parameters.Add(new ValueParameter<ISelector>(SelectorParameterName, "The inner selection operator to select the parents."));
60      Parameters.Add(new ValueParameter<PercentValue>(QualityDifferencePercentageParameterName, "The minimum quality difference from parent1 to parent2 to accept the selection.", new PercentValue(0.05)));
61      Parameters.Add(new ValueParameter<IntValue>(QualityDifferenceMaxAttemptsParameterName, "The maximum number of attempts to find parents which differ in quality.", new IntValue(5)));
62      #endregion
63
64      Initialize();
65    }
66
67    [StorableHook(HookType.AfterDeserialization)]
68    private void AfterDeserialization() {
69      Initialize();
70    }
71
72    protected override IScope[] Select(List<IScope> scopes) {
73      int count = NumberOfSelectedSubScopes.Value;
74      if (count % 2 > 0) throw new InvalidOperationException(Name + ": There must be an equal number of sub-scopes to be selected.");
75      IScope[] selected = new IScope[count];
76
77      double qualityDifferencePercentage = QualityDifferencePercentage.Value;
78      int qualityDifferenceMaxAttempts = QualityDifferenceMaxAttempts.Value;
79   
80      int attempts = 1;
81      int j = 0;
82      while (j < count - 1) { // repeat until enough parents are selected
83        ApplyInnerSelector();
84        ScopeList parents = CurrentScope.SubScopes[1].SubScopes;
85
86        for (int i = 0; j < count - 1 && i < parents.Count / 2; i++) {
87          double qualityParent1 = ((DoubleValue)parents[i * 2].Variables[QualityParameter.ActualName].Value).Value;
88          double qualityParent2 = ((DoubleValue)parents[i * 2 + 1].Variables[QualityParameter.ActualName].Value).Value;
89
90          bool parentsDifferent = (qualityParent2 > qualityParent1 * (1.0 + qualityDifferencePercentage) ||
91                                   qualityParent2 < qualityParent1 * (1.0 - qualityDifferencePercentage));
92          // parents meet difference criterion or max attempts reached
93          if (attempts >= qualityDifferenceMaxAttempts || parentsDifferent) {
94     
95            // inner selector already copied scopes
96            selected[j++] = parents[i * 2];
97            selected[j++] = parents[i * 2 + 1];
98            if (!CopySelected.Value) {
99              scopes.Remove(parents[i * 2]);
100              scopes.Remove(parents[i * 2 + 1]);
101            }
102            attempts = 1;
103          } else { // skip parents
104            attempts++;
105          }
106        }
107        // modify scopes
108        ScopeList remaining = CurrentScope.SubScopes[0].SubScopes;
109        CurrentScope.SubScopes.Clear();
110        CurrentScope.SubScopes.AddRange(remaining);
111      }
112      return selected;
113    }
114
115    #region Events
116    private void SelectorParameter_ValueChanged(object sender, EventArgs e) {
117      IValueParameter<ISelector> selectorParam = (sender as IValueParameter<ISelector>);
118      if (selectorParam != null)
119        ParameterizeSelector(selectorParam.Value);
120    }
121    #endregion
122
123    #region Helpers
124    private void ApplyInnerSelector() {
125      IOperation next;
126      IAtomicOperation operation;
127      OperationCollection coll;
128      Stack<IOperation> executionStack = new Stack<IOperation>();
129
130      executionStack.Push(ExecutionContext.CreateChildOperation(Selector));
131      while (executionStack.Count > 0) {
132        CancellationToken.ThrowIfCancellationRequested();
133        next = executionStack.Pop();
134        if (next is OperationCollection) {
135          coll = (OperationCollection)next;
136          for (int i = coll.Count - 1; i >= 0; i--)
137            if (coll[i] != null) executionStack.Push(coll[i]);
138        } else if (next is IAtomicOperation) {
139          operation = (IAtomicOperation)next;
140          next = operation.Operator.Execute((IExecutionContext)operation, CancellationToken);
141          if (next != null) executionStack.Push(next);
142        }
143      }
144    }
145
146    private void Initialize() {
147      SelectorParameter.ValueChanged += new EventHandler(SelectorParameter_ValueChanged);
148      if (Selector == null) Selector = new TournamentSelector();
149    }
150
151    private void ParameterizeSelector(ISelector selector) {
152      selector.CopySelected = new BoolValue(true); // must always be true
153      IStochasticOperator stoOp = (selector as IStochasticOperator);
154      if (stoOp != null) stoOp.RandomParameter.ActualName = RandomParameter.Name;
155      ISingleObjectiveSelector soSelector = (selector as ISingleObjectiveSelector);
156      if (soSelector != null) {
157        soSelector.MaximizationParameter.ActualName = MaximizationParameter.Name;
158        soSelector.QualityParameter.ActualName = QualityParameter.Name;
159      }
160    }
161    #endregion
162  }
163}
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