1  #region License Information


2  /* HeuristicLab


3  * Copyright (C) 20022018 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.Linq;


25  using HeuristicLab.Common;


26  using HeuristicLab.Core;


27  using HeuristicLab.Data;


28  using HeuristicLab.Parameters;


29  using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;


30 


31  namespace HeuristicLab.Problems.DataAnalysis {


32  [Item("Logarithm", "Logarithm transformation x' = log(x, Base)")]


33  [StorableClass]


34  public class LogarithmTransformation : Transformation<double> {


35  #region Parameters


36  private FixedValueParameter<DoubleValue> BaseParameter {


37  get { return (FixedValueParameter<DoubleValue>)Parameters["Base"]; }


38  }


39  #endregion


40 


41  #region Properties


42  public double Base {


43  get { return BaseParameter.Value.Value; }


44  set { BaseParameter.Value.Value = value; }


45  }


46  #endregion


47 


48  #region Constructor, Cloning & Persistence


49  public LogarithmTransformation()


50  : base() {


51  Parameters.Add(new FixedValueParameter<DoubleValue>("Base", "Base the logarithm", new DoubleValue(Math.E)));


52  }


53 


54  protected LogarithmTransformation(LogarithmTransformation original, Cloner cloner)


55  : base(original, cloner) {


56  }


57  public override IDeepCloneable Clone(Cloner cloner) {


58  return new LogarithmTransformation(this, cloner);


59  }


60 


61  [StorableConstructor]


62  protected LogarithmTransformation(bool deserializing)


63  : base(deserializing) {


64  }


65  #endregion


66 


67  public override bool Check(IEnumerable<double> data, out string errorMessage) {


68  if (data.Any(x => x <= 0)) {


69  errorMessage = "Log is not available for zero or negative values";


70  return false;


71  }


72  return base.Check(data, out errorMessage);


73  }


74 


75  public override IEnumerable<double> Apply(IEnumerable<double> data) {


76  return Apply(data, Base);


77  }


78 


79  public override IEnumerable<double> InverseApply(IEnumerable<double> data) {


80  return InverseApply(data, Base);


81  }


82 


83 


84  public static IEnumerable<double> Apply(IEnumerable<double> data, double @base = Math.E) {


85  return data.Select(x => Math.Log(x, @base));


86  }


87 


88  public static IEnumerable<double> InverseApply(IEnumerable<double> data, double @base = Math.E) {


89  return ExponentialTransformation.Apply(data, @base);


90  }


91  }


92  } 
