Ticket #1040: CrowdedComparisonSorter.cs

#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2008 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.Collections.Generic;
using System.Linq;
using System.Text;
using HeuristicLab.Core;
using HeuristicLab.Common;
using HeuristicLab.Data;
using HeuristicLab.DataAnalysis;
using HeuristicLab.Modeling;
using HeuristicLab.GP;
using HeuristicLab.GP.StructureIdentification;
using HeuristicLab.GP.Interfaces;

namespace HeuristicLab.LinearRegression {
  /// <summary>
  /// CrowdedComparisonSorter as described in: Deb, Pratap, Agrawal and Meyarivan, "A Fast and Elitist Multiobjective
  /// Genetic Algorithm: NSGA-II", IEEE Transactions On Evolutionary Computation, Vol. 6, No. 2, April 2002
  /// </summary>
  public class CrowdedComparisonSorter : OperatorBase {

    public override string Description {
      get {
        return
@"CrowdedComparisonSorter as described in: Deb, Pratap, Agrawal and Meyarivan, ""A Fast and Elitist Multiobjective
Genetic Algorithm: NSGA-II"", IEEE Transactions On Evolutionary Computation, Vol. 6, No. 2, April 2002";
      }
    }

    public CrowdedComparisonSorter() {
    }

    public override IOperation Apply(IScope scope) {
      var scopes = new List<IScope>(scope.SubScopes);

      scopes.Sort((a, b) => {
        if (GetRank(a) < GetRank(b)) return -1;
        else if (GetRank(a) > GetRank(b)) return 1;
        else { // ranks are the same -> compare by distance
          if (GetDistance(a) > GetDistance(b)) return -1;
          else if (GetDistance(a) < GetDistance(b)) return 1;
          else return 0; // same distance
        }
      });

      while (scope.SubScopes.Count > 0) scope.RemoveSubScope(scope.SubScopes[0]);
      foreach (var subScope in scopes) {
        scope.AddSubScope(subScope);
      }

      return null;
    }

    private double GetRank(IScope a) {
      return a.GetVariableValue<DoubleData>("Rank", false).Data;
    }

    private double GetDistance(IScope a) {
      return a.GetVariableValue<DoubleData>("Distance", false).Data;
    }
  }
}