#region License Information
/* HeuristicLab
* Copyright (C) 2002-2018 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
*
* This file is part of HeuristicLab.
*
* HeuristicLab is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* HeuristicLab is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with HeuristicLab. If not, see .
*/
#endregion
using System;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
namespace HeuristicLab.Optimization.Operators {
///
/// Modifies the value by exponential fall (steep fall initially, slow fall to the end) or rise (slow rise initially, fast rise to the end).
///
[Item("ExponentialDiscreteDoubleValueModifier",
@"Modifies the value by exponential fall (steep fall initially, slow fall to the end) or rise (slow rise initially, fast rise to the end).
This uses a standard exponential distribution and yields a base which is implicitly derived by start and end indices and values.")]
[StorableClass]
public class ExponentialDiscreteDoubleValueModifier : DiscreteDoubleValueModifier {
[StorableConstructor]
protected ExponentialDiscreteDoubleValueModifier(bool deserializing) : base(deserializing) { }
protected ExponentialDiscreteDoubleValueModifier(ExponentialDiscreteDoubleValueModifier original, Cloner cloner) : base(original, cloner) { }
public ExponentialDiscreteDoubleValueModifier() : base() { }
public override IDeepCloneable Clone(Cloner cloner) {
return new ExponentialDiscreteDoubleValueModifier(this, cloner);
}
///
/// Calculates a new value based on exponential decay or growth.
///
/// Thrown when endValue or startValue or both are 0.
/// The last value.
/// The start value.
/// The end value.
/// The current index.
/// The start index.
/// The end index.
/// The new value.
protected override double Modify(double value, double startValue, double endValue, int index, int startIndex, int endIndex) {
if (endValue <= 0 || startValue <= 0) throw new ArgumentException("startValue and endValue must be greater than 0.");
double b = Math.Pow(endValue / startValue, 1.0 / (endIndex - startIndex));
return startValue * Math.Pow(b, index - startIndex);
}
}
}