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source: trunk/sources/HeuristicLab.Random/3.3/UniformRandomizer.cs @ 2524

Last change on this file since 2524 was 2524, checked in by swagner, 14 years ago

Removed plugin HeuristicLab.Constraints (#804)

File size: 6.7 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.Persistence.Default.CompositeSerializers.Storable;
28
29namespace HeuristicLab.Random {
30  /// <summary>
31  /// Uniformly distributed random number generator.
32  /// </summary>
33  [EmptyStorableClass]
34  public class UniformRandomizer : OperatorBase {
35    private static int MAX_NUMBER_OF_TRIES = 100;
36    /// <inheritdoc select="summary"/>
37    public override string Description {
38      get { return "Initializes the value of variable 'Value' to a random value uniformly distributed between 'Min' and 'Max' (exclusive)"; }
39    }
40
41    /// <summary>
42    /// Gets or sets the maximum value of the random number generator (exclusive).
43    /// </summary>
44    /// <remarks>Gets or sets the variable with name <c>Max</c> through the
45    /// <see cref="OperatorBase.GetVariable"/> method of class <see cref="OperatorBase"/>.</remarks>
46    public double Max {
47      get { return ((DoubleData)GetVariable("Max").Value).Data; }
48      set { ((DoubleData)GetVariable("Max").Value).Data = value; }
49    }
50    /// <summary>
51    /// Gets or sets the minimum value of the random number generator.
52    /// </summary>
53    /// <remarks>Gets or sets the variable with name <c>Min</c> through the
54    /// <see cref="OperatorBase.GetVariable"/> method of class <see cref="OperatorBase"/>.</remarks>
55    public double Min {
56      get { return ((DoubleData)GetVariable("Min").Value).Data; }
57      set { ((DoubleData)GetVariable("Min").Value).Data = value; }
58    }
59
60    /// <summary>
61    /// Initializes a new instance of <see cref="UniformRandomizer"/> with four variable infos
62    /// (<c>Value</c>, <c>Random</c>, <c>Max</c> and <c>Min</c>), being a random number generator
63    /// between 0.0 and 1.0.
64    /// </summary>
65    public UniformRandomizer() {
66      AddVariableInfo(new VariableInfo("Value", "The value to manipulate (type is one of: IntData, ConstrainedIntData, DoubleData, ConstrainedDoubleData)", typeof(IObjectData), VariableKind.In));
67      AddVariableInfo(new VariableInfo("Random", "The random generator to use", typeof(MersenneTwister), VariableKind.In));
68      AddVariableInfo(new VariableInfo("Min", "Lower bound of the uniform distribution (inclusive)", typeof(DoubleData), VariableKind.None));
69      GetVariableInfo("Min").Local = true;
70      AddVariable(new Variable("Min", new DoubleData(0.0)));
71
72      AddVariableInfo(new VariableInfo("Max", "Upper bound of the uniform distribution (exclusive)", typeof(DoubleData), VariableKind.None));
73      GetVariableInfo("Max").Local = true;
74      AddVariable(new Variable("Max", new DoubleData(1.0)));
75    }
76
77    /// <summary>
78    /// Generates a new uniformly distributed random variable.
79    /// </summary>
80    /// <param name="scope">The scope where to apply the random number generator.</param>
81    /// <returns><c>null</c>.</returns>
82    public override IOperation Apply(IScope scope) {
83      IObjectData value = GetVariableValue<IObjectData>("Value", scope, false);
84      MersenneTwister mt = GetVariableValue<MersenneTwister>("Random", scope, true);
85      double min = GetVariableValue<DoubleData>("Min", scope, true).Data;
86      double max = GetVariableValue<DoubleData>("Max", scope, true).Data;
87
88      RandomizeUniform(value, mt, min, max);
89      return null;
90    }
91
92    /// <summary>
93    /// Generates a new random number depending on the type of the <paramref name="value"/>.
94    /// </summary>
95    /// <exception cref="ArgumentException">Thrown when an unhandleable type appears.</exception>
96    /// <param name="value">The object whose data should be a new randomly generated number.</param>
97    /// <param name="mt">The MersenneTwister to generate a new random number.</param>
98    /// <param name="min">The left border of the interval in which the next random number has to lie.</param>
99    /// <param name="max">The right border (exclusive) of the interval in which the next random number
100    /// has to lie.</param>
101    private void RandomizeUniform(IObjectData value, MersenneTwister mt, double min, double max) {
102      // Dispatch manually based on dynamic type,
103      // a bit awkward but necessary until we create a better type hierarchy for numeric types (gkronber 15.11.2008).
104      if (value is DoubleData)
105        RandomizeUniform((DoubleData)value, mt, min, max);
106      else if (value is IntData)
107        RandomizeUniform((IntData)value, mt, min, max);
108      else throw new ArgumentException("Can't handle type " + value.GetType().Name);
109    }
110
111      /// <summary>
112      /// Generates a new double random number.
113      /// </summary>
114      /// <param name="data">The double object which the new value is assigned to.</param>
115      /// <param name="mt">The random number generator.</param>
116      /// <param name="min">The left border of the interval in which the next random number has to lie.</param>
117      /// <param name="max">The right border (exclusive) of the interval in which the next random number
118      /// has to lie.</param>
119      public void RandomizeUniform(DoubleData data, MersenneTwister mt, double min, double max) {
120        data.Data = mt.NextDouble() * (max - min) + min;
121      }
122
123      /// <summary>
124      /// Generates a new int random number.
125      /// </summary>
126      /// <param name="data">The int object which the new value is assigned to.</param>
127      /// <param name="mt">The random number generator.</param>
128      /// <param name="min">The left border of the interval in which the next random number has to lie.</param>
129      /// <param name="max">The right border (exclusive) of the interval in which the next random number
130      /// has to lie.</param>
131      public void RandomizeUniform(IntData data, MersenneTwister mt, double min, double max) {
132        data.Data = (int)Math.Floor(mt.NextDouble() * (max - min) + min);
133      }
134    }
135}
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