#region License Information
/* HeuristicLab
* Copyright (C) 2002-2011 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 System.Collections.Generic;
using System.Linq;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Data;
using HeuristicLab.Operators;
using HeuristicLab.Optimization;
using HeuristicLab.Parameters;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
using SVM;
namespace HeuristicLab.Problems.DataAnalysis.SupportVectorMachine {
///
/// Represents an operator that performs SVM cross validation with the given parameters.
///
[StorableClass]
[Item("SupportVectorMachineCrossValidationEvaluator", "Represents an operator that performs SVM cross validation with the given parameters.")]
public class SupportVectorMachineCrossValidationEvaluator : SingleSuccessorOperator, ISingleObjectiveEvaluator {
private const string RandomParameterName = "Random";
private const string DataAnalysisProblemDataParameterName = "DataAnalysisProblemData";
private const string SvmTypeParameterName = "SvmType";
private const string KernelTypeParameterName = "KernelType";
private const string CostParameterName = "Cost";
private const string NuParameterName = "Nu";
private const string GammaParameterName = "Gamma";
private const string EpsilonParameterName = "Epsilon";
private const string SamplesStartParameterName = "SamplesStart";
private const string SamplesEndParameterName = "SamplesEnd";
private const string ActualSamplesParameterName = "ActualSamples";
private const string NumberOfFoldsParameterName = "NumberOfFolds";
private const string QualityParameterName = "Quality";
#region parameter properties
public ILookupParameter RandomParameter {
get { return (ILookupParameter)Parameters[RandomParameterName]; }
}
public IValueLookupParameter DataAnalysisProblemDataParameter {
get { return (IValueLookupParameter)Parameters[DataAnalysisProblemDataParameterName]; }
}
public IValueLookupParameter SvmTypeParameter {
get { return (IValueLookupParameter)Parameters[SvmTypeParameterName]; }
}
public IValueLookupParameter KernelTypeParameter {
get { return (IValueLookupParameter)Parameters[KernelTypeParameterName]; }
}
public IValueLookupParameter NuParameter {
get { return (IValueLookupParameter)Parameters[NuParameterName]; }
}
public IValueLookupParameter CostParameter {
get { return (IValueLookupParameter)Parameters[CostParameterName]; }
}
public IValueLookupParameter GammaParameter {
get { return (IValueLookupParameter)Parameters[GammaParameterName]; }
}
public IValueLookupParameter EpsilonParameter {
get { return (IValueLookupParameter)Parameters[EpsilonParameterName]; }
}
public IValueLookupParameter SamplesStartParameter {
get { return (IValueLookupParameter)Parameters[SamplesStartParameterName]; }
}
public IValueLookupParameter SamplesEndParameter {
get { return (IValueLookupParameter)Parameters[SamplesEndParameterName]; }
}
public IValueLookupParameter ActualSamplesParameter {
get { return (IValueLookupParameter)Parameters[ActualSamplesParameterName]; }
}
public IValueLookupParameter NumberOfFoldsParameter {
get { return (IValueLookupParameter)Parameters[NumberOfFoldsParameterName]; }
}
public ILookupParameter QualityParameter {
get { return (ILookupParameter)Parameters[QualityParameterName]; }
}
#endregion
#region properties
public DataAnalysisProblemData DataAnalysisProblemData {
get { return DataAnalysisProblemDataParameter.ActualValue; }
}
public StringValue SvmType {
get { return SvmTypeParameter.ActualValue; }
}
public StringValue KernelType {
get { return KernelTypeParameter.ActualValue; }
}
public DoubleValue Nu {
get { return NuParameter.ActualValue; }
}
public DoubleValue Cost {
get { return CostParameter.ActualValue; }
}
public DoubleValue Gamma {
get { return GammaParameter.ActualValue; }
}
public DoubleValue Epsilon {
get { return EpsilonParameter.ActualValue; }
}
public IntValue SamplesStart {
get { return SamplesStartParameter.ActualValue; }
}
public IntValue SamplesEnd {
get { return SamplesEndParameter.ActualValue; }
}
public IntValue NumberOfFolds {
get { return NumberOfFoldsParameter.ActualValue; }
}
#endregion
[StorableConstructor]
protected SupportVectorMachineCrossValidationEvaluator(bool deserializing) : base(deserializing) { }
protected SupportVectorMachineCrossValidationEvaluator(SupportVectorMachineCrossValidationEvaluator original,
Cloner cloner)
: base(original, cloner) { }
public SupportVectorMachineCrossValidationEvaluator()
: base() {
Parameters.Add(new LookupParameter(RandomParameterName, "The random generator to use."));
Parameters.Add(new ValueLookupParameter(DataAnalysisProblemDataParameterName, "The data analysis problem data to use for training."));
Parameters.Add(new ValueLookupParameter(SvmTypeParameterName, "The type of SVM to use."));
Parameters.Add(new ValueLookupParameter(KernelTypeParameterName, "The kernel type to use for the SVM."));
Parameters.Add(new ValueLookupParameter(NuParameterName, "The value of the nu parameter nu-SVC, one-class SVM and nu-SVR."));
Parameters.Add(new ValueLookupParameter(CostParameterName, "The value of the C (cost) parameter of C-SVC, epsilon-SVR and nu-SVR."));
Parameters.Add(new ValueLookupParameter(GammaParameterName, "The value of the gamma parameter in the kernel function."));
Parameters.Add(new ValueLookupParameter(EpsilonParameterName, "The value of the epsilon parameter for epsilon-SVR."));
Parameters.Add(new ValueLookupParameter(SamplesStartParameterName, "The first index of the data set partition the support vector machine should use for training."));
Parameters.Add(new ValueLookupParameter(SamplesEndParameterName, "The last index of the data set partition the support vector machine should use for training."));
Parameters.Add(new ValueLookupParameter(ActualSamplesParameterName, "The percentage of the training set that should be acutally used for cross-validation (samples are picked randomly from the training set)."));
Parameters.Add(new ValueLookupParameter(NumberOfFoldsParameterName, "The number of folds to use for cross-validation."));
Parameters.Add(new LookupParameter(QualityParameterName, "The cross validation quality reached with the given parameters."));
}
public override IDeepCloneable Clone(Cloner cloner) {
return new SupportVectorMachineCrossValidationEvaluator(this, cloner);
}
public override IOperation Apply() {
double reductionRatio = 1.0; // TODO: make parameter
if (ActualSamplesParameter.ActualValue != null)
reductionRatio = ActualSamplesParameter.ActualValue.Value;
IEnumerable rows =
Enumerable.Range(SamplesStart.Value, SamplesEnd.Value - SamplesStart.Value)
.Where(i => i < DataAnalysisProblemData.TestSamplesStart.Value || DataAnalysisProblemData.TestSamplesEnd.Value <= i);
// create a new DataAnalysisProblemData instance
DataAnalysisProblemData reducedProblemData = (DataAnalysisProblemData)DataAnalysisProblemData.Clone();
reducedProblemData.Dataset =
CreateReducedDataset(RandomParameter.ActualValue, reducedProblemData.Dataset, rows, reductionRatio);
reducedProblemData.TrainingSamplesStart.Value = 0;
reducedProblemData.TrainingSamplesEnd.Value = reducedProblemData.Dataset.Rows;
reducedProblemData.TestSamplesStart.Value = reducedProblemData.Dataset.Rows;
reducedProblemData.TestSamplesEnd.Value = reducedProblemData.Dataset.Rows;
reducedProblemData.ValidationPercentage.Value = 0;
double quality = PerformCrossValidation(reducedProblemData,
SvmType.Value, KernelType.Value,
Cost.Value, Nu.Value, Gamma.Value, Epsilon.Value, NumberOfFolds.Value);
QualityParameter.ActualValue = new DoubleValue(quality);
return base.Apply();
}
private Dataset CreateReducedDataset(IRandom random, Dataset dataset, IEnumerable rowIndices, double reductionRatio) {
// must not make a fink:
// => select n rows randomly from start..end
// => sort the selected rows by index
// => move rows to beginning of partition (start)
// all possible rowIndexes from start..end
int[] rowIndexArr = rowIndices.ToArray();
int n = (int)Math.Max(1.0, rowIndexArr.Length * reductionRatio);
// knuth shuffle
for (int i = rowIndexArr.Length - 1; i > 0; i--) {
int j = random.Next(0, i);
// swap
int tmp = rowIndexArr[i];
rowIndexArr[i] = rowIndexArr[j];
rowIndexArr[j] = tmp;
}
// take the first n indexes (selected n rowIndexes from start..end)
// now order by index
int[] orderedRandomIndexes =
rowIndexArr.Take(n)
.OrderBy(x => x)
.ToArray();
// now build a dataset containing only rows from orderedRandomIndexes
double[,] reducedData = new double[n, dataset.Columns];
for (int i = 0; i < n; i++) {
for (int column = 0; column < dataset.Columns; column++) {
reducedData[i, column] = dataset[orderedRandomIndexes[i], column];
}
}
return new Dataset(dataset.VariableNames, reducedData);
}
private static double PerformCrossValidation(
DataAnalysisProblemData problemData,
string svmType, string kernelType,
double cost, double nu, double gamma, double epsilon,
int nFolds) {
return PerformCrossValidation(problemData, problemData.TrainingIndizes, svmType, kernelType, cost, nu, gamma, epsilon, nFolds);
}
public static double PerformCrossValidation(
DataAnalysisProblemData problemData,
IEnumerable rowIndices,
string svmType, string kernelType,
double cost, double nu, double gamma, double epsilon,
int nFolds) {
int targetVariableIndex = problemData.Dataset.GetVariableIndex(problemData.TargetVariable.Value);
//extract SVM parameters from scope and set them
SVM.Parameter parameter = new SVM.Parameter();
parameter.SvmType = (SVM.SvmType)Enum.Parse(typeof(SVM.SvmType), svmType, true);
parameter.KernelType = (SVM.KernelType)Enum.Parse(typeof(SVM.KernelType), kernelType, true);
parameter.C = cost;
parameter.Nu = nu;
parameter.Gamma = gamma;
parameter.P = epsilon;
parameter.CacheSize = 500;
parameter.Probability = false;
SVM.Problem problem = SupportVectorMachineUtil.CreateSvmProblem(problemData, rowIndices);
SVM.RangeTransform rangeTransform = SVM.RangeTransform.Compute(problem);
SVM.Problem scaledProblem = Scaling.Scale(rangeTransform, problem);
return SVM.Training.PerformCrossValidation(scaledProblem, parameter, nFolds, false);
}
}
}