Free cookie consent management tool by TermsFeed Policy Generator

source: trunk/sources/HeuristicLab.Random/UniformRandomAdder.cs @ 1157

Last change on this file since 1157 was 1157, checked in by vdorfer, 15 years ago

Created API documentation for HeuristicLab.IntVector namespace and changed some comments in HeuristicLab.Random and HeuristicLab.Selection.Offspring namespace(#331)

File size: 8.7 KB
Line 
1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2008 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.Text;
25using HeuristicLab.Core;
26using HeuristicLab.Data;
27using HeuristicLab.Constraints;
28
29namespace HeuristicLab.Random {
30  /// <summary>
31  /// Uniformly distributed random number generator that adds the generated value to the existing one.
32  /// </summary>
33  public class UniformRandomAdder : OperatorBase {
34
35    private static int MAX_NUMBER_OF_TRIES = 100;
36
37    /// <inheritdoc select="summary"/>
38    public override string Description {
39      get {
40        return @"Samples a uniformly distributed random variable 'U' with range = [min,max] and E(u) = (max-min)/2
41and adds the result to the variable 'Value'. ShakingFactor influences the effective range of U.
42If r=(max-min) then the effective range of U is [E(u) - shakingFactor * r/2, E(u) + shakingFactor * r/2].
43
44If a constraint for the allowed range of 'Value' is defined and the result of the operation would be smaller then
45the smallest allowed value then 'Value' is set to the lower bound and vice versa for the upper bound.";
46      }
47    }
48
49    /// <summary>
50    /// Initializes a new instance of <see cref="UniformRandomAdder"/> with five variable infos
51    /// (<c>Value</c>, <c>ShakingFactor</c>, <c>Random</c>, <c>Min</c> and <c>Max</c>), having an interval
52    /// of -1.0 to 1.0.
53    /// </summary>
54    public UniformRandomAdder() {
55      AddVariableInfo(new VariableInfo("Value", "The value to manipulate (type is one of: IntData, ConstrainedIntData, DoubleData, ConstrainedDoubleData)", typeof(IObjectData), VariableKind.In));
56      AddVariableInfo(new VariableInfo("ShakingFactor", "Determines the force of the shaking factor", typeof(DoubleData), VariableKind.In));
57      AddVariableInfo(new VariableInfo("Random", "The random generator to use", typeof(MersenneTwister), VariableKind.In));
58      AddVariableInfo(new VariableInfo("Min", "Lower bound of the uniform distribution (inclusive)", typeof(DoubleData), VariableKind.None));
59      GetVariableInfo("Min").Local = true;
60      AddVariable(new Variable("Min", new DoubleData(-1.0)));
61
62      AddVariableInfo(new VariableInfo("Max", "Upper bound of the uniform distribution (exclusive)", typeof(DoubleData), VariableKind.None));
63      GetVariableInfo("Max").Local = true;
64      AddVariable(new Variable("Max", new DoubleData(1.0)));
65    }
66
67    /// <summary>
68    /// Generates a new uniformly distributed random number and adds it to the value in the given
69    /// <paramref name="scope"/>.
70    /// </summary>
71    /// <param name="scope">The current scope where to add the generated random number.</param>
72    /// <returns><c>null</c>.</returns>
73    public override IOperation Apply(IScope scope) {
74      IObjectData value = GetVariableValue<IObjectData>("Value", scope, false);
75      MersenneTwister mt = GetVariableValue<MersenneTwister>("Random", scope, true);
76      double factor = GetVariableValue<DoubleData>("ShakingFactor", scope, true).Data;
77      double min = GetVariableValue<DoubleData>("Min", scope, true).Data;
78      double max = GetVariableValue<DoubleData>("Max", scope, true).Data;
79
80      double ex = (max - min) / 2.0 + min;
81      double newRange = (max - min) * factor;
82      min = ex - newRange / 2;
83      max = ex + newRange / 2;
84
85      AddUniform(value, mt, min, max);
86      return null;
87    }
88
89    private void AddUniform(IObjectData value, MersenneTwister mt, double min, double max) {
90      // dispatch manually on dynamic type
91      if (value is IntData)
92        AddUniform((IntData)value, mt, min, max);
93      else if (value is ConstrainedIntData)
94        AddUniform((ConstrainedIntData)value, mt, min, max);
95      else if (value is DoubleData)
96        AddUniform((DoubleData)value, mt, min, max);
97      else if (value is ConstrainedDoubleData)
98        AddUniform((ConstrainedDoubleData)value, mt, min, max);
99      else throw new InvalidOperationException("Can't handle type " + value.GetType().Name);
100    }
101
102    /// <summary>
103    /// Adds a new double random variable being restricted to some constraints to the value of the given
104    /// <paramref name="data"/>.
105    /// </summary>
106    /// <exception cref="InvalidProgramException">Thrown when no valid value can be found.</exception>
107    /// <param name="data">The data where to add the new variable and where to assign the new value to.</param>
108    /// <param name="mt">The random number generator.</param>
109    /// <param name="min">The left border of the interval in which the next random number has to lie.</param>
110    /// <param name="max">The right border (exclusive) of the interval in which the next random number
111    /// has to lie.</param>
112    public void AddUniform(ConstrainedDoubleData data, MersenneTwister mt, double min, double max) {
113      for (int tries = MAX_NUMBER_OF_TRIES; tries >= 0; tries--) {
114        double newValue = data.Data + mt.NextDouble() * (max - min) + min;
115        if (IsIntegerConstrained(data)) {
116          newValue = Math.Floor(newValue);
117        }
118        if (data.TrySetData(newValue)) {
119          return;
120        }
121      }
122      throw new InvalidProgramException("Couldn't find a valid value");
123    }
124
125    /// <summary>
126    /// Adds a new int random variable being restricted to some constraints to the value of the given
127    /// <paramref name="data"/>.
128    /// </summary>
129    /// <exception cref="InvalidProgramException">Thrown when no valid value could be found.</exception>
130    /// <param name="data">The data where to add the random value and where to assign the new value to.</param>
131    /// <param name="mt">The random number generator.</param>
132    /// <param name="min">The left border of the interval in which the next random number has to lie.</param>
133    /// <param name="max">The right border (exclusive) of the interval in which the next random number
134    /// has to lie.</param>
135    public void AddUniform(ConstrainedIntData data, MersenneTwister mt, double min, double max) {
136      for (int tries = MAX_NUMBER_OF_TRIES; tries >= 0; tries--) {
137        int newValue = (int)Math.Floor(data.Data + mt.NextDouble() * (max - min) + min);
138        if (data.TrySetData(newValue)) {
139          return;
140        }
141      }
142      throw new InvalidProgramException("Couldn't find a valid value");
143    }
144
145    /// <summary>
146    /// Generates a new double random variable and adds it to the value of
147    /// the given <paramref name="data"/>.
148    /// </summary>
149    /// <param name="data">The double object where to add the random value.</param>
150    /// <param name="mt">The random number generator.</param>
151    /// <param name="min">The left border of the interval in which the next random number has to lie.</param>
152    /// <param name="max">The right border (exclusive) of the interval in which the next random number
153    /// has to lie.</param>
154    public void AddUniform(DoubleData data, MersenneTwister mt, double min, double max) {
155      data.Data = data.Data + mt.NextDouble() * (max - min) + min;
156    }
157
158    /// <summary>
159    /// Generates a new int random variable and adds it to the value of the given
160    /// <paramref name="data"/>.
161    /// </summary>
162    /// <param name="data">The int object where to add the random value.</param>
163    /// <param name="mt">The random number generator.</param>
164    /// <param name="min">The left border of the interval in which the next random number has to lie.</param>
165    /// <param name="max">The right border (exclusive) of the interval in which the next random number
166    /// has to lie.</param>
167    public void AddUniform(IntData data, MersenneTwister mt, double min, double max) {
168      data.Data = (int)Math.Floor(data.Data + mt.NextDouble() * (max - min) + min);
169    }
170    private bool IsIntegerConstrained(ConstrainedDoubleData data) {
171      foreach (IConstraint constraint in data.Constraints) {
172        if (constraint is IsIntegerConstraint) {
173          return true;
174        }
175      }
176      return false;
177    }
178  }
179}
Note: See TracBrowser for help on using the repository browser.