1  #region License Information


2  /* HeuristicLab


3  * Copyright (C) 20022015 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.Persistence.Default.CompositeSerializers.Storable;


28 


29  namespace HeuristicLab.Algorithms.DataAnalysis {


30  [StorableClass]


31  [Item(Name = "CovarianceSum",


32  Description = "Sum covariance function for Gaussian processes.")]


33  public sealed class CovarianceSum : Item, ICovarianceFunction {


34  [Storable]


35  private ItemList<ICovarianceFunction> terms;


36 


37  [Storable]


38  private int numberOfVariables;


39  public ItemList<ICovarianceFunction> Terms {


40  get { return terms; }


41  }


42 


43  [StorableConstructor]


44  private CovarianceSum(bool deserializing)


45  : base(deserializing) {


46  }


47 


48  private CovarianceSum(CovarianceSum original, Cloner cloner)


49  : base(original, cloner) {


50  this.terms = cloner.Clone(original.terms);


51  this.numberOfVariables = original.numberOfVariables;


52  }


53 


54  public CovarianceSum()


55  : base() {


56  this.terms = new ItemList<ICovarianceFunction>();


57  }


58 


59  public override IDeepCloneable Clone(Cloner cloner) {


60  return new CovarianceSum(this, cloner);


61  }


62 


63  public int GetNumberOfParameters(int numberOfVariables) {


64  this.numberOfVariables = numberOfVariables;


65  return terms.Select(t => t.GetNumberOfParameters(numberOfVariables)).Sum();


66  }


67 


68  public void SetParameter(double[] p) {


69  int offset = 0;


70  foreach (var t in terms) {


71  var numberOfParameters = t.GetNumberOfParameters(numberOfVariables);


72  t.SetParameter(p.Skip(offset).Take(numberOfParameters).ToArray());


73  offset += numberOfParameters;


74  }


75  }


76 


77  public ParameterizedCovarianceFunction GetParameterizedCovarianceFunction(double[] p, int[] columnIndices) {


78  if (terms.Count == 0) throw new ArgumentException("at least one term is necessary for the product covariance function.");


79  var functions = new List<ParameterizedCovarianceFunction>();


80  foreach (var t in terms) {


81  var numberOfParameters = t.GetNumberOfParameters(numberOfVariables);


82  functions.Add(t.GetParameterizedCovarianceFunction(p.Take(numberOfParameters).ToArray(), columnIndices));


83  p = p.Skip(numberOfParameters).ToArray();


84  }


85 


86  var sum = new ParameterizedCovarianceFunction();


87  sum.Covariance = (x, i, j) => functions.Select(e => e.Covariance(x, i, j)).Sum();


88  sum.CrossCovariance = (x, xt, i, j) => functions.Select(e => e.CrossCovariance(x, xt, i, j)).Sum();


89  sum.CovarianceGradient = (x, i, j) => functions.Select(e => e.CovarianceGradient(x, i, j)).Aggregate(Enumerable.Concat);


90  return sum;


91  }


92  }


93  }

