1  #region License Information


2  /* HeuristicLab


3  * Copyright (C) 20022008 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 


22  using System;


23  using System.Collections.Generic;


24  using System.Text;


25  using HeuristicLab.Core;


26  using HeuristicLab.Data;


27  using HeuristicLab.Constraints;


28 


29  namespace 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) = (maxmin)/2


41  and adds the result to the variable 'Value'. ShakingFactor influences the effective range of U.


42  If r=(maxmin) then the effective range of U is [E(u)  shakingFactor * r/2, E(u) + shakingFactor * r/2].


43 


44  If a constraint for the allowed range of 'Value' is defined and the result of the operation would be smaller then


45  the 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>null.</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  }

