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source: trunk/sources/HeuristicLab.Operators/3.3/StochasticMultiBranch.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: 9.0 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;
23using System.Collections.Generic;
24using System.Linq;
25using HeuristicLab.Collections;
26using HeuristicLab.Common;
27using HeuristicLab.Core;
28using HeuristicLab.Data;
29using HeuristicLab.Parameters;
30using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
31
32namespace HeuristicLab.Operators {
33  /// <summary>
34  /// Selects one of its branches (if there are any) given a list of relative probabilities.
35  /// </summary>
36  [Item("StochasticMultiBranch", "Selects one of its branches (if there are any) given a list of relative probabilities.")]
37  [StorableClass]
38  public abstract class StochasticMultiBranch<T> : CheckedMultiOperator<T> where T : class, IOperator {
39    /// <summary>
40    /// Should return true if the StochasticMultiOperator should create a new child operation with the selected successor
41    /// or if it should create a new operation. If you need to shield the parameters of the successor you should return true here.
42    /// </summary>
43    protected abstract bool CreateChildOperation { get; }
44
45    public ValueLookupParameter<DoubleArray> ProbabilitiesParameter {
46      get { return (ValueLookupParameter<DoubleArray>)Parameters["Probabilities"]; }
47    }
48    public ILookupParameter<IRandom> RandomParameter {
49      get { return (ILookupParameter<IRandom>)Parameters["Random"]; }
50    }
51    public ValueParameter<BoolValue> TraceSelectedOperatorParameter {
52      get { return (ValueParameter<BoolValue>)Parameters["TraceSelectedOperator"]; }
53    }
54    public LookupParameter<StringValue> SelectedOperatorParameter {
55      get { return (LookupParameter<StringValue>)Parameters["SelectedOperator"]; }
56    }
57
58    public DoubleArray Probabilities {
59      get { return ProbabilitiesParameter.Value; }
60      set { ProbabilitiesParameter.Value = value; }
61    }
62
63    [StorableHook(HookType.AfterDeserialization)]
64    private void AfterDeserializationHook() {
65      #region Backwards Compatibility
66      if (!Parameters.ContainsKey("SelectedOperator")) {
67        Parameters.Add(new LookupParameter<StringValue>("SelectedOperator", "If the TraceSelectedOperator flag is set, the name of the operator is traced in this parameter."));
68        SelectedOperatorParameter.Hidden = false;
69      }
70      if (!Parameters.ContainsKey("TraceSelectedOperator")) {
71        Parameters.Add(new ValueParameter<BoolValue>("TraceSelectedOperator", "Indicates, if the selected operator should be traced.", new BoolValue(false)));
72      }
73      #endregion
74    }
75
76    [StorableConstructor]
77    protected StochasticMultiBranch(bool deserializing) : base(deserializing) { }
78    protected StochasticMultiBranch(StochasticMultiBranch<T> original, Cloner cloner)
79      : base(original, cloner) {
80    }
81    /// <summary>
82    /// Initializes a new instance of <see cref="StochasticMultiOperator"/> with two parameters
83    /// (<c>Probabilities</c> and <c>Random</c>).
84    /// </summary>
85    public StochasticMultiBranch()
86      : base() {
87      Parameters.Add(new ValueLookupParameter<DoubleArray>("Probabilities", "The array of relative probabilities for each operator.", new DoubleArray()));
88      Parameters.Add(new LookupParameter<IRandom>("Random", "The random number generator to use."));
89      Parameters.Add(new LookupParameter<StringValue>("SelectedOperator", "If the TraceSelectedOperator flag is set, the name of the operator is traced in this parameter."));
90      Parameters.Add(new ValueParameter<BoolValue>("TraceSelectedOperator", "Indicates, if the selected operator should be traced.", new BoolValue(false)));
91      SelectedOperatorParameter.Hidden = false;
92    }
93
94    protected override void Operators_ItemsRemoved(object sender, CollectionItemsChangedEventArgs<IndexedItem<T>> e) {
95      base.Operators_ItemsRemoved(sender, e);
96      if (Probabilities != null && Probabilities.Length > Operators.Count) {
97        List<double> probs = new List<double>(Probabilities.Cast<double>());
98        var sorted = e.Items.OrderByDescending(x => x.Index);
99        foreach (IndexedItem<T> item in sorted)
100          if (probs.Count > item.Index) probs.RemoveAt(item.Index);
101        Probabilities = new DoubleArray(probs.ToArray());
102      }
103    }
104
105    protected override void Operators_ItemsAdded(object sender, HeuristicLab.Collections.CollectionItemsChangedEventArgs<IndexedItem<T>> e) {
106      base.Operators_ItemsAdded(sender, e);
107      if (Probabilities != null && Probabilities.Length < Operators.Count) {
108        double avg = (Probabilities.Where(x => x > 0).Count() > 0) ? (Probabilities.Where(x => x > 0).Average()) : (1);
109        // add the average of all probabilities in the respective places (the new operators)
110        var added = e.Items.OrderBy(x => x.Index).ToList();
111        int insertCount = 0;
112        DoubleArray probs = new DoubleArray(Operators.Count);
113        for (int i = 0; i < Operators.Count; i++) {
114          if (insertCount < added.Count && i == added[insertCount].Index) {
115            probs[i] = avg;
116            insertCount++;
117          } else if (i - insertCount < Probabilities.Length) {
118            probs[i] = Probabilities[i - insertCount];
119          } else probs[i] = avg;
120        }
121        Probabilities = probs;
122      }
123    }
124
125    /// <summary>
126    /// Applies an operator of the branches to the current scope with a
127    /// specific probability.
128    /// </summary>
129    /// <exception cref="InvalidOperationException">Thrown when the list of probabilites does not
130    /// match the number of operators, the list of selected operators is empty,
131    /// or all selected operators have zero probabitlity.</exception>
132    /// <returns>A new operation with the operator that was selected followed by the current operator's successor.</returns>
133    public override IOperation Apply() {
134      IRandom random = RandomParameter.ActualValue;
135      DoubleArray probabilities = ProbabilitiesParameter.ActualValue;
136      if (probabilities.Length != Operators.Count) {
137        throw new InvalidOperationException(Name + ": The list of probabilities has to match the number of operators");
138      }
139      IOperator successor = null;
140      int index = -1;
141      var checkedOperators = Operators.CheckedItems;
142      if (checkedOperators.Count() > 0) {
143        // select a random operator from the checked operators
144        double sum = (from indexedItem in checkedOperators select probabilities[indexedItem.Index]).Sum();
145        if (sum == 0) throw new InvalidOperationException(Name + ": All selected operators have zero probability.");
146        double r = random.NextDouble() * sum;
147        sum = 0;
148        foreach (var indexedItem in checkedOperators) {
149          sum += probabilities[indexedItem.Index];
150          if (sum > r) {
151            successor = indexedItem.Value;
152            index = indexedItem.Index;
153            break;
154          }
155        }
156      }
157      OperationCollection next = new OperationCollection(base.Apply());
158      if (successor != null) {
159        if (TraceSelectedOperatorParameter.Value.Value)
160          SelectedOperatorParameter.ActualValue = new StringValue(index + ": " + successor.Name);
161
162        if (CreateChildOperation)
163          next.Insert(0, ExecutionContext.CreateChildOperation(successor));
164        else next.Insert(0, ExecutionContext.CreateOperation(successor));
165      } else {
166        if (TraceSelectedOperatorParameter.Value.Value)
167          SelectedOperatorParameter.ActualValue = new StringValue("");
168      }
169      return next;
170    }
171  }
172
173  /// <summary>
174  /// Selects one of its branches (if there are any) given a list of relative probabilities.
175  /// </summary>
176  [Item("StochasticMultiBranch", "Selects one of its branches (if there are any) given a list of relative probabilities.")]
177  [StorableClass]
178  public class StochasticMultiBranch : StochasticMultiBranch<IOperator> {
179    [StorableConstructor]
180    protected StochasticMultiBranch(bool deserializing) : base(deserializing) { }
181    protected StochasticMultiBranch(StochasticMultiBranch original, Cloner cloner)
182      : base(original, cloner) {
183    }
184    public StochasticMultiBranch() { }
185
186    public override IDeepCloneable Clone(Cloner cloner) {
187      return new StochasticMultiBranch(this, cloner);
188    }
189
190    protected override bool CreateChildOperation {
191      get { return false; }
192    }
193  }
194}
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