source: branches/VOSGA/HeuristicLab.Algorithms.VOffspringSelectionGeneticAlgorithm/WeightedParentsDiversityComparator.cs @ 11614

#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2014 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 <http://www.gnu.org/licenses/>.
 */
#endregion

using System;
using System.Linq;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Data;
using HeuristicLab.Operators;
using HeuristicLab.Optimization;
using HeuristicLab.Optimization.Operators;
using HeuristicLab.Parameters;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
using HeuristicLab.PluginInfrastructure;

namespace HeuristicLab.Algorithms.VOffspringSelectionGeneticAlgorithm {
  [Item("WeightedParentsDiversityComparator", "Compares the similarity against that of its parents (assumes the parents are subscopes to the child scope). This operator works with any number of subscopes > 0.")]
  [StorableClass]
  public class WeightedParentsDiversityComparator : SingleSuccessorOperator, ISubScopesQualityComparatorOperator, ISimilarityBasedOperator {
    [Storable]
    public ISolutionSimilarityCalculator SimilarityCalculator { get; set; }
    public IValueLookupParameter<BoolValue> MaximizationParameter {
      get { return (IValueLookupParameter<BoolValue>)Parameters["Maximization"]; }
    }
    public ILookupParameter<DoubleValue> LeftSideParameter {
      get { return (ILookupParameter<DoubleValue>)Parameters["LeftSide"]; }
    }
    public ILookupParameter<ItemArray<DoubleValue>> RightSideParameter {
      get { return (ILookupParameter<ItemArray<DoubleValue>>)Parameters["RightSide"]; }
    }
    public ILookupParameter<BoolValue> ResultParameter {
      get { return (ILookupParameter<BoolValue>)Parameters["Result"]; }
    }
    public ValueLookupParameter<DoubleValue> ComparisonFactorParameter {
      get { return (ValueLookupParameter<DoubleValue>)Parameters["ComparisonFactor"]; }
    }
    public ValueLookupParameter<DoubleValue> DiversityComparisonFactorParameter {
      get { return (ValueLookupParameter<DoubleValue>)Parameters["DiversityComparisonFactor"]; }
    }
    private ValueLookupParameter<DoubleValue> ComparisonFactorLowerBoundParameter {
      get { return (ValueLookupParameter<DoubleValue>)Parameters["DiversityComparisonFactorLowerBound"]; }
    }
    private ValueLookupParameter<DoubleValue> ComparisonFactorUpperBoundParameter {
      get { return (ValueLookupParameter<DoubleValue>)Parameters["DiversityComparisonFactorUpperBound"]; }
    }
    public IConstrainedValueParameter<IDiscreteDoubleValueModifier> ComparisonFactorModifierParameter {
      get { return (IConstrainedValueParameter<IDiscreteDoubleValueModifier>)Parameters["ComparisonFactorModifier"]; }
    }

    [StorableConstructor]
    protected WeightedParentsDiversityComparator(bool deserializing) : base(deserializing) { }
    protected WeightedParentsDiversityComparator(WeightedParentsDiversityComparator original, Cloner cloner) : base(original, cloner) { }
    public WeightedParentsDiversityComparator()
      : base() {
      Parameters.Add(new ValueLookupParameter<BoolValue>("Maximization", "True if the problem is a maximization problem, false otherwise"));
      Parameters.Add(new LookupParameter<DoubleValue>("LeftSide", "The quality of the child."));
      Parameters.Add(new ScopeTreeLookupParameter<DoubleValue>("RightSide", "The qualities of the parents."));
      Parameters.Add(new LookupParameter<BoolValue>("Result", "The result of the comparison: True means Quality is better, False means it is worse than parents."));
      Parameters.Add(new ValueLookupParameter<DoubleValue>("ComparisonFactor", "Determines if the quality should be compared to the better parent (1.0), to the worse (0.0) or to any linearly interpolated value between them."));
      Parameters.Add(new ValueLookupParameter<DoubleValue>("DiversityComparisonFactor", "Determines if the quality should be compared to the better parent (1.0), to the worse (0.0) or to any linearly interpolated value between them.", new DoubleValue(0.0)));
      Parameters.Add(new ValueLookupParameter<DoubleValue>("DiversityComparisonFactorLowerBound", "The lower bound of the comparison factor (start).", new DoubleValue(0.5)));
      Parameters.Add(new ValueLookupParameter<DoubleValue>("DiversityComparisonFactorUpperBound", "The upper bound of the comparison factor (end).", new DoubleValue(1.0)));
      Parameters.Add(new OptionalConstrainedValueParameter<IDiscreteDoubleValueModifier>("ComparisonFactorModifier", "The operator used to modify the comparison factor.", new ItemSet<IDiscreteDoubleValueModifier>(new IDiscreteDoubleValueModifier[] { new LinearDiscreteDoubleValueModifier() }), new LinearDiscreteDoubleValueModifier()));

      foreach (IDiscreteDoubleValueModifier modifier in ApplicationManager.Manager.GetInstances<IDiscreteDoubleValueModifier>().OrderBy(x => x.Name))
        ComparisonFactorModifierParameter.ValidValues.Add(modifier);
      IDiscreteDoubleValueModifier linearModifier = ComparisonFactorModifierParameter.ValidValues.FirstOrDefault(x => x.GetType().Name.Equals("LinearDiscreteDoubleValueModifier"));
      if (linearModifier != null) ComparisonFactorModifierParameter.Value = linearModifier;
      ParameterizeComparisonFactorModifiers();
    }

    public override IDeepCloneable Clone(Cloner cloner) {
      return new WeightedParentsDiversityComparator(this, cloner);
    }

    private void ParameterizeComparisonFactorModifiers() {
      //TODO: does not work if Generations parameter names are changed
      foreach (IDiscreteDoubleValueModifier modifier in ComparisonFactorModifierParameter.ValidValues) {
        modifier.IndexParameter.ActualName = "Generations";
        modifier.EndIndexParameter.ActualName = "MaximumGenerations";
        modifier.EndValueParameter.ActualName = ComparisonFactorUpperBoundParameter.Name;
        modifier.StartIndexParameter.Value = new IntValue(0);
        modifier.StartValueParameter.ActualName = ComparisonFactorLowerBoundParameter.Name;
        modifier.ValueParameter.ActualName = "DiversityComparisonFactor";
      }
    }

    public override IOperation Apply() {
      ItemArray<DoubleValue> rightQualities = RightSideParameter.ActualValue;
      if (rightQualities.Length < 1) throw new InvalidOperationException(Name + ": No subscopes found.");
      double compFact = ComparisonFactorParameter.ActualValue.Value;
      double diversityComFact = DiversityComparisonFactorParameter.ActualValue.Value;
      bool maximization = MaximizationParameter.ActualValue.Value;
      double leftQuality = LeftSideParameter.ActualValue.Value;
      bool resultDiversity;

      double threshold = 0;

      #region Calculate threshold
      if (rightQualities.Length == 2) {
        var sim1 = SimilarityCalculator.CalculateSolutionSimilarity(ExecutionContext.Scope, ExecutionContext.Scope.SubScopes[0]);
        var sim2 = SimilarityCalculator.CalculateSolutionSimilarity(ExecutionContext.Scope, ExecutionContext.Scope.SubScopes[1]);
        var simAvg = (sim1 + sim2) / 2.0;

        //TODO: try out different things
        //resultDiversity = simAvg < diversityComFact;
        resultDiversity = sim1 < diversityComFact || sim2 < diversityComFact;

        double minQuality = Math.Min(rightQualities[0].Value, rightQualities[1].Value);
        double maxQuality = Math.Max(rightQualities[0].Value, rightQualities[1].Value);
        if (maximization)
          threshold = minQuality + (maxQuality - minQuality) * compFact;
        else
          threshold = maxQuality - (maxQuality - minQuality) * compFact;
      } else {
        throw new NotImplementedException("Only 2 parents are supported.");
      }
      #endregion

      bool result = maximization && leftQuality > threshold || !maximization && leftQuality < threshold;
      result = result && resultDiversity;
      BoolValue resultValue = ResultParameter.ActualValue;
      if (resultValue == null) {
        ResultParameter.ActualValue = new BoolValue(result);
      } else {
        resultValue.Value = result;
      }

      //like the placeholder, though we create child operations
      OperationCollection next = new OperationCollection(base.Apply());
      IOperator op = ComparisonFactorModifierParameter.Value;
      if (op != null)
        next.Insert(0, ExecutionContext.CreateChildOperation(op));
      return next;
    }
  }
}