HeuristicLab.Optimization.Operators/3.3/ExponentialDiscreteDoubleValueModifier.cs

   1 #region License Information
   2 /* HeuristicLab
   3  * Copyright (C) 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 HeuristicLab.Common;
  24 using HeuristicLab.Core;
  25 using HEAL.Attic;
  26
  27 namespace HeuristicLab.Optimization.Operators {
  28   /// <summary>
  29   /// Modifies the value by exponential fall (steep fall initially, slow fall to the end) or rise (slow rise initially, fast rise to the end).
  30   /// </summary>
  31   [Item("ExponentialDiscreteDoubleValueModifier",
  32 @"Modifies the value by exponential fall (steep fall initially, slow fall to the end) or rise (slow rise initially, fast rise to the end).
  33 This uses a standard exponential distribution and yields a base which is implicitly derived by start and end indices and values.")]
  34   [StorableType("9DEDC020-F9A5-4067-AC23-7A29B656E818")]
  35   public class ExponentialDiscreteDoubleValueModifier : DiscreteDoubleValueModifier {
  36     [StorableConstructor]
  37     protected ExponentialDiscreteDoubleValueModifier(StorableConstructorFlag _) : base(_) { }
  38     protected ExponentialDiscreteDoubleValueModifier(ExponentialDiscreteDoubleValueModifier original, Cloner cloner) : base(original, cloner) { }
  39     public ExponentialDiscreteDoubleValueModifier() : base() { }
  40
  41     public override IDeepCloneable Clone(Cloner cloner) {
  42       return new ExponentialDiscreteDoubleValueModifier(this, cloner);
  43     }
  44
  45
  46     protected override double Modify(double value, double startValue, double endValue, int index, int startIndex, int endIndex) {
  47       return Apply(value, startValue, endValue, index, startIndex, endIndex);
  48     }
  49
  50     /// <summary>
  51     /// Calculates a new value based on exponential decay or growth.
  52     /// </summary>
  53     /// <exception cref="ArgumentException">Thrown when endValue or startValue or both are 0.</exception>
  54     /// <param name="value">The last value.</param>
  55     /// <param name="startValue">The start value.</param>
  56     /// <param name="endValue">The end value.</param>
  57     /// <param name="index">The current index.</param>
  58     /// <param name="startIndex">The start index.</param>
  59     /// <param name="endIndex">The end index.</param>
  60     /// <returns>The new value.</returns>
  61     public static double Apply(double value, double startValue, double endValue, int index, int startIndex, int endIndex) {
  62       if (endValue <= 0 || startValue <= 0) throw new ArgumentException("startValue and endValue must be greater than 0.");
  63       double b = Math.Pow(endValue / startValue, 1.0 / (endIndex - startIndex));
  64       return startValue * Math.Pow(b, index - startIndex);
  65     }
  66   }
  67 }