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source: branches/SuccessProgressAnalysis/HeuristicLab.Operators/3.3/StochasticMultiBranch.cs @ 5682

Last change on this file since 5682 was 5682, checked in by svonolfe, 12 years ago

Implemented review comments from swagner (#1392)

File size: 9.0 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;
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 ValueLookupParameter<StringValue> SelectedOperatorParameter {
55      get { return (ValueLookupParameter<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 ValueLookupParameter<StringValue>("SelectedOperator", "If the TraceSelectedOperator flag is set, the name of the operator is traced in this parameter."));
68      }
69      if (!Parameters.ContainsKey("TraceSelectedOperator")) {
70        Parameters.Add(new ValueParameter<BoolValue>("TraceSelectedOperator", "Indicates, if the selected operator should be traced.", new BoolValue(false)));
71      }
72      #endregion
73    }
74
75    [StorableConstructor]
76    protected StochasticMultiBranch(bool deserializing) : base(deserializing) { }
77    protected StochasticMultiBranch(StochasticMultiBranch<T> original, Cloner cloner)
78      : base(original, cloner) {
79    }
80    /// <summary>
81    /// Initializes a new instance of <see cref="StochasticMultiOperator"/> with two parameters
82    /// (<c>Probabilities</c> and <c>Random</c>).
83    /// </summary>
84    public StochasticMultiBranch()
85      : base() {
86      Parameters.Add(new ValueLookupParameter<DoubleArray>("Probabilities", "The array of relative probabilities for each operator.", new DoubleArray()));
87      Parameters.Add(new LookupParameter<IRandom>("Random", "The random number generator to use."));
88      Parameters.Add(new ValueLookupParameter<StringValue>("SelectedOperator", "If the TraceSelectedOperator flag is set, the name of the operator is traced in this parameter."));
89      Parameters.Add(new ValueParameter<BoolValue>("TraceSelectedOperator", "Indicates, if the selected operator should be traced.", new BoolValue(false)));
90    }
91
92    protected override void Operators_ItemsRemoved(object sender, CollectionItemsChangedEventArgs<IndexedItem<T>> e) {
93      base.Operators_ItemsRemoved(sender, e);
94      if (Probabilities != null && Probabilities.Length > Operators.Count) {
95        List<double> probs = new List<double>(Probabilities.Cast<double>());
96        var sorted = e.Items.OrderByDescending(x => x.Index);
97        foreach (IndexedItem<T> item in sorted)
98          if (probs.Count > item.Index) probs.RemoveAt(item.Index);
99        Probabilities = new DoubleArray(probs.ToArray());
100      }
101    }
102
103    protected override void Operators_ItemsAdded(object sender, HeuristicLab.Collections.CollectionItemsChangedEventArgs<IndexedItem<T>> e) {
104      base.Operators_ItemsAdded(sender, e);
105      if (Probabilities != null && Probabilities.Length < Operators.Count) {
106        double avg = (Probabilities.Where(x => x > 0).Count() > 0) ? (Probabilities.Where(x => x > 0).Average()) : (1);
107        // add the average of all probabilities in the respective places (the new operators)
108        var added = e.Items.OrderBy(x => x.Index).ToList();
109        int insertCount = 0;
110        DoubleArray probs = new DoubleArray(Operators.Count);
111        for (int i = 0; i < Operators.Count; i++) {
112          if (insertCount < added.Count && i == added[insertCount].Index) {
113            probs[i] = avg;
114            insertCount++;
115          } else if (i - insertCount < Probabilities.Length) {
116            probs[i] = Probabilities[i - insertCount];
117          } else probs[i] = avg;
118        }
119        Probabilities = probs;
120      }
121    }
122
123    /// <summary>
124    /// Applies an operator of the branches to the current scope with a
125    /// specific probability.
126    /// </summary>
127    /// <exception cref="InvalidOperationException">Thrown when the list of probabilites does not
128    /// match the number of operators, the list of selected operators is empty,
129    /// or all selected operators have zero probabitlity.</exception>
130    /// <returns>A new operation with the operator that was selected followed by the current operator's successor.</returns>
131    public override IOperation Apply() {
132      IRandom random = RandomParameter.ActualValue;
133      DoubleArray probabilities = ProbabilitiesParameter.ActualValue;
134      if (probabilities.Length != Operators.Count) {
135        throw new InvalidOperationException(Name + ": The list of probabilities has to match the number of operators");
136      }
137      IOperator successor = null;
138      int index = -1;
139      var checkedOperators = Operators.CheckedItems;
140      if (checkedOperators.Count() > 0) {
141        // select a random operator from the checked operators
142        double sum = (from indexedItem in checkedOperators select probabilities[indexedItem.Index]).Sum();
143        if (sum == 0) throw new InvalidOperationException(Name + ": All selected operators have zero probability.");
144        double r = random.NextDouble() * sum;
145        sum = 0;
146        foreach (var indexedItem in checkedOperators) {
147          sum += probabilities[indexedItem.Index];
148          if (sum > r) {
149            successor = indexedItem.Value;
150            index = indexedItem.Index;
151            break;
152          }
153        }
154      }
155      OperationCollection next = new OperationCollection(base.Apply());
156      if (successor != null) {
157        if (TraceSelectedOperatorParameter.Value.Value)
158          SelectedOperatorParameter.ActualValue = new StringValue(index + ": " + successor.Name);
159
160        if (CreateChildOperation)
161          next.Insert(0, ExecutionContext.CreateChildOperation(successor));
162        else next.Insert(0, ExecutionContext.CreateOperation(successor));
163      } else {
164        if (TraceSelectedOperatorParameter.Value.Value)
165          SelectedOperatorParameter.ActualValue = new StringValue("");
166      }
167      return next;
168    }
169  }
170
171  /// <summary>
172  /// Selects one of its branches (if there are any) given a list of relative probabilities.
173  /// </summary>
174  [Item("StochasticMultiBranch", "Selects one of its branches (if there are any) given a list of relative probabilities.")]
175  [StorableClass]
176  public class StochasticMultiBranch : StochasticMultiBranch<IOperator> {
177    [StorableConstructor]
178    protected StochasticMultiBranch(bool deserializing) : base(deserializing) { }
179    protected StochasticMultiBranch(StochasticMultiBranch original, Cloner cloner)
180      : base(original, cloner) {
181    }
182    public StochasticMultiBranch() { }
183
184    public override IDeepCloneable Clone(Cloner cloner) {
185      return new StochasticMultiBranch(this, cloner);
186    }
187
188    protected override bool CreateChildOperation {
189      get { return false; }
190    }
191  }
192}
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