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source: branches/SuccessProgressAnalysis/HeuristicLab.Operators/3.3/StochasticMultiBranch.cs @ 5372

Last change on this file since 5372 was 5372, checked in by svonolfe, 14 years ago

Implemented first version of success progress analysis (#1392)

File size: 8.1 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 ValueLookupParameter<StringValue> ExecutedOperatorParameter {
52      get { return (ValueLookupParameter<StringValue>)Parameters["ExecutedOperator"]; }
53    }
54
55    public DoubleArray Probabilities {
56      get { return ProbabilitiesParameter.Value; }
57      set { ProbabilitiesParameter.Value = value; }
58    }
59
60    [StorableHook(HookType.AfterDeserialization)]
61    private void AfterDeserializationHook() {
62      #region Backwards Compatibility
63      if (!Parameters.ContainsKey("ExecutedOperator")) {
64        Parameters.Add(new ValueLookupParameter<StringValue>("ExecutedOperator", "The operator that was executed."));
65      }
66      #endregion
67    }
68
69    [StorableConstructor]
70    protected StochasticMultiBranch(bool deserializing) : base(deserializing) { }
71    protected StochasticMultiBranch(StochasticMultiBranch<T> original, Cloner cloner)
72      : base(original, cloner) {
73    }
74    /// <summary>
75    /// Initializes a new instance of <see cref="StochasticMultiOperator"/> with two parameters
76    /// (<c>Probabilities</c> and <c>Random</c>).
77    /// </summary>
78    public StochasticMultiBranch()
79      : base() {
80      Parameters.Add(new ValueLookupParameter<DoubleArray>("Probabilities", "The array of relative probabilities for each operator.", new DoubleArray()));
81      Parameters.Add(new LookupParameter<IRandom>("Random", "The random number generator to use."));
82      Parameters.Add(new ValueLookupParameter<StringValue>("ExecutedOperator", "The operator that was executed."));
83    }
84
85    protected override void Operators_ItemsRemoved(object sender, CollectionItemsChangedEventArgs<IndexedItem<T>> e) {
86      base.Operators_ItemsRemoved(sender, e);
87      if (Probabilities != null && Probabilities.Length > Operators.Count) {
88        List<double> probs = new List<double>(Probabilities.Cast<double>());
89        var sorted = e.Items.OrderByDescending(x => x.Index);
90        foreach (IndexedItem<T> item in sorted)
91          if (probs.Count > item.Index) probs.RemoveAt(item.Index);
92        Probabilities = new DoubleArray(probs.ToArray());
93      }
94    }
95
96    protected override void Operators_ItemsAdded(object sender, HeuristicLab.Collections.CollectionItemsChangedEventArgs<IndexedItem<T>> e) {
97      base.Operators_ItemsAdded(sender, e);
98      if (Probabilities != null && Probabilities.Length < Operators.Count) {
99        double avg = (Probabilities.Where(x => x > 0).Count() > 0) ? (Probabilities.Where(x => x > 0).Average()) : (1);
100        // add the average of all probabilities in the respective places (the new operators)
101        var added = e.Items.OrderBy(x => x.Index).ToList();
102        int insertCount = 0;
103        DoubleArray probs = new DoubleArray(Operators.Count);
104        for (int i = 0; i < Operators.Count; i++) {
105          if (insertCount < added.Count && i == added[insertCount].Index) {
106            probs[i] = avg;
107            insertCount++;
108          } else if (i - insertCount < Probabilities.Length) {
109            probs[i] = Probabilities[i - insertCount];
110          } else probs[i] = avg;
111        }
112        Probabilities = probs;
113      }
114    }
115
116    /// <summary>
117    /// Applies an operator of the branches to the current scope with a
118    /// specific probability.
119    /// </summary>
120    /// <exception cref="InvalidOperationException">Thrown when the list of probabilites does not
121    /// match the number of operators, the list of selected operators is empty,
122    /// or all selected operators have zero probabitlity.</exception>
123    /// <returns>A new operation with the operator that was selected followed by the current operator's successor.</returns>
124    public override IOperation Apply() {
125      IRandom random = RandomParameter.ActualValue;
126      DoubleArray probabilities = ProbabilitiesParameter.ActualValue;
127      if (probabilities.Length != Operators.Count) {
128        throw new InvalidOperationException(Name + ": The list of probabilities has to match the number of operators");
129      }
130      IOperator successor = null;
131      var checkedOperators = Operators.CheckedItems;
132      if (checkedOperators.Count() > 0) {
133        // select a random operator from the checked operators
134        double sum = (from indexedItem in checkedOperators select probabilities[indexedItem.Index]).Sum();
135        if (sum == 0) throw new InvalidOperationException(Name + ": All selected operators have zero probability.");
136        double r = random.NextDouble() * sum;
137        sum = 0;
138        foreach (var indexedItem in checkedOperators) {
139          sum += probabilities[indexedItem.Index];
140          if (sum > r) {
141            successor = indexedItem.Value;
142            break;
143          }
144        }
145      }
146      OperationCollection next = new OperationCollection(base.Apply());
147      if (successor != null) {
148        ExecutedOperatorParameter.ActualValue = new StringValue(successor.GetType().Name);
149
150        if (CreateChildOperation)
151          next.Insert(0, ExecutionContext.CreateChildOperation(successor));
152        else next.Insert(0, ExecutionContext.CreateOperation(successor));
153      } else {
154        ExecutedOperatorParameter.ActualValue = new StringValue("");
155      }
156      return next;
157    }
158  }
159
160  /// <summary>
161  /// Selects one of its branches (if there are any) given a list of relative probabilities.
162  /// </summary>
163  [Item("StochasticMultiBranch", "Selects one of its branches (if there are any) given a list of relative probabilities.")]
164  [StorableClass]
165  public class StochasticMultiBranch : StochasticMultiBranch<IOperator> {
166    [StorableConstructor]
167    protected StochasticMultiBranch(bool deserializing) : base(deserializing) { }
168    protected StochasticMultiBranch(StochasticMultiBranch original, Cloner cloner)
169      : base(original, cloner) {
170    }
171    public StochasticMultiBranch() { }
172
173    public override IDeepCloneable Clone(Cloner cloner) {
174      return new StochasticMultiBranch(this, cloner);
175    }
176
177    protected override bool CreateChildOperation {
178      get { return false; }
179    }
180  }
181}
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