source: trunk/sources/HeuristicLab.Encodings.RealVectorEncoding/3.3/Manipulators/MichalewiczNonUniformAllPositionsManipulator.cs @ 3677

Last change on this file since 3677 was 3677, checked in by abeham, 12 years ago

#890

  • updated MichalewiczNonUniform(All|One)PositionsManipulator to default to "Generations" and added better explanation of one of the parameters
File size: 7.6 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 HeuristicLab.Common;
24using HeuristicLab.Core;
25using HeuristicLab.Data;
26using HeuristicLab.Parameters;
27using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
28
29namespace HeuristicLab.Encodings.RealVectorEncoding {
30  /// <summary>
31  /// The solution is manipulated with diminishing strength over time. In addition the mutated values are not sampled over the entire domain, but additive.<br/>
32  /// Initially, the space will be searched uniformly and very locally at later stages. This increases the probability of generating the new numbers closer to the current value.
33  /// </summary>
34  /// <remarks>
35  /// It is implemented as described in Michalewicz, Z. 1999. Genetic Algorithms + Data Structures = Evolution Programs. Third, Revised and Extended Edition, Spring-Verlag Berlin Heidelberg.
36  /// </remarks>
37  [Item("MichalewiczNonUniformAllPositionsManipulator", "It is implemented as described in Michalewicz, Z. 1999. Genetic Algorithms + Data Structures = Evolution Programs. Third, Revised and Extended Edition, Spring-Verlag Berlin Heidelberg.")]
38  [StorableClass]
39  public class MichalewiczNonUniformAllPositionsManipulator : RealVectorManipulator {
40    /// <summary>
41    /// The current generation.
42    /// </summary>
43    public LookupParameter<IntValue> GenerationParameter {
44      get { return (LookupParameter<IntValue>)Parameters["Generations"]; }
45    }
46    /// <summary>
47    /// The maximum generation.
48    /// </summary>
49    public LookupParameter<IntValue> MaximumGenerationsParameter {
50      get { return (LookupParameter<IntValue>)Parameters["MaximumGenerations"]; }
51    }
52    /// <summary>
53    /// The parameter describing how much the mutation should depend on the progress towards the maximum generation.
54    /// </summary>
55    public ValueLookupParameter<DoubleValue> GenerationDependencyParameter {
56      get { return (ValueLookupParameter<DoubleValue>)Parameters["GenerationDependency"]; }
57    }
58
59    /// <summary>
60    /// Initializes a new instance of <see cref="MichalewiczNonUniformAllPositionsManipulator"/> with
61    /// four parameters (<c>Bounds</c>, <c>CurrentGeneration</c>,
62    /// <c>MaximumGenerations</c> and <c>GenerationDependency</c>).
63    /// </summary>
64    public MichalewiczNonUniformAllPositionsManipulator()
65      : base() {
66      Parameters.Add(new LookupParameter<IntValue>("Generations", "Current generation of the algorithm"));
67      Parameters.Add(new LookupParameter<IntValue>("MaximumGenerations", "Maximum number of generations"));
68      Parameters.Add(new ValueLookupParameter<DoubleValue>("GenerationDependency", "Specifies the degree of dependency on the number of generations. A value of 0 means no dependency and the higher the value the stronger the progress towards maximum generations will be taken into account by sampling closer around the current position. Value must be >= 0.", new DoubleValue(5)));
69    }
70
71    /// <summary>
72    /// Performs a non uniformly distributed all position manipulation on the given
73    /// real <paramref name="vector"/>. The probability of stronger mutations reduces the more <see cref="currentGeneration"/> approaches <see cref="maximumGenerations"/>.
74    /// </summary>
75    /// <exception cref="ArgumentException">Thrown when <paramref name="currentGeneration"/> is greater than <paramref name="maximumGenerations"/>.</exception>
76    /// <param name="random">The random number generator.</param>
77    /// <param name="vector">The real vector to manipulate.</param>
78    /// <param name="bounds">The lower and upper bound (1st and 2nd column) of the positions in the vector. If there are less rows than dimensions, the rows are cycled.</param>
79    /// <param name="currentGeneration">The current generation of the algorithm.</param>
80    /// <param name="maximumGenerations">Maximum number of generations.</param>
81    /// <param name="generationsDependency">Specifies the degree of dependency on the number of generations. A value of 0 means no dependency and the higher the value the stronger the progress towards maximum generations will be taken into account by sampling closer around the current position. Value must be >= 0.</param>
82    /// <returns>The manipulated real vector.</returns>
83    public static void Apply(IRandom random, RealVector vector, DoubleMatrix bounds, IntValue currentGeneration, IntValue maximumGenerations, DoubleValue generationsDependency) {
84      if (currentGeneration.Value > maximumGenerations.Value) throw new ArgumentException("MichalewiczNonUniformAllPositionManipulator: CurrentGeneration must be smaller or equal than MaximumGeneration", "currentGeneration");
85      if (generationsDependency.Value < 0) throw new ArgumentException("MichalewiczNonUniformOnePositionManipulator: GenerationsDependency must be >= 0.");
86      int length = vector.Length;
87
88      double prob = Math.Pow(1 - currentGeneration.Value / maximumGenerations.Value, generationsDependency.Value);
89
90      for (int i = 0; i < length; i++) {
91        double min = bounds[i % bounds.Rows, 0];
92        double max = bounds[i % bounds.Rows, 1];
93        if (random.NextDouble() < 0.5) {
94          vector[i] = vector[i] + (max - vector[i]) * (1 - Math.Pow(random.NextDouble(), prob));
95        } else {
96          vector[i] = vector[i] - (vector[i] - min) * (1 - Math.Pow(random.NextDouble(), prob));
97        }
98      }
99    }
100
101    /// <summary>
102    /// Checks if all parameters are available and forwards the call to <see cref="Apply(IRandom, RealVector, DoubleValue, DoubleValue, IntValue, IntValue, DoubleValue)"/>.
103    /// </summary>
104    /// <param name="random">The random number generator.</param>
105    /// <param name="realVector">The real vector that should be manipulated.</param>
106    protected override void Manipulate(IRandom random, RealVector realVector) {
107      if (BoundsParameter.ActualValue == null) throw new InvalidOperationException("MichalewiczNonUniformAllPositionManipulator: Parameter " + BoundsParameter.ActualName + " could not be found.");
108      if (GenerationParameter.ActualValue == null) throw new InvalidOperationException("MichalewiczNonUniformAllPositionManipulator: Parameter " + GenerationParameter.ActualName + " could not be found.");
109      if (MaximumGenerationsParameter.ActualValue == null) throw new InvalidOperationException("MichalewiczNonUniformAllPositionManipulator: Parameter " + MaximumGenerationsParameter.ActualName + " could not be found.");
110      if (GenerationDependencyParameter.ActualValue == null) throw new InvalidOperationException("MichalewiczNonUniformAllPositionManipulator: Parameter " + GenerationDependencyParameter.ActualName + " could not be found.");
111      Apply(random, realVector, BoundsParameter.ActualValue, GenerationParameter.ActualValue, MaximumGenerationsParameter.ActualValue, GenerationDependencyParameter.ActualValue);
112    }
113  }
114}
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