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source: trunk/sources/HeuristicLab.Problems.TestFunctions.MultiObjective/3.3/NonDominatedSelect.cs @ 15568

Last change on this file since 15568 was 14185, checked in by swagner, 8 years ago

#2526: Updated year of copyrights in license headers

File size: 3.5 KB
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[13562]1#region License Information
2/* HeuristicLab
[14185]3 * Copyright (C) 2002-2016 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
[13562]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
22using System.Collections.Generic;
23
[14111]24namespace HeuristicLab.Problems.TestFunctions.MultiObjective {
[13562]25
[14085]26  public static class NonDominatedSelect {
[14018]27    public enum DominationResult { Dominates, IsDominated, IsNonDominated };
[13562]28
[14081]29    public static IEnumerable<double[]> SelectNonDominatedVectors(IEnumerable<double[]> qualities, bool[] maximization, bool dominateOnEqualQualities) {
[13562]30
[13988]31      List<double[]> front = new List<double[]>();
32      foreach (double[] row in qualities) {
33        bool insert = true;
34        for (int i = 0; i < front.Count; i++) {
35          DominationResult res = Dominates(front[i], row, maximization, dominateOnEqualQualities);
36          if (res == DominationResult.Dominates) { insert = false; break; }           //Vector domiates Row
37          else if (res == DominationResult.IsDominated) {   //Row dominates Vector
[14081]38            front.RemoveAt(i);
[13988]39          }
[13562]40        }
[13988]41        if (insert) {
42          front.Add(row);
[13562]43        }
[13988]44      }
[13562]45
[13988]46      return front;
47    }
[13562]48
[14081]49    public static IEnumerable<double[]> GetDominatingVectors(IEnumerable<double[]> qualities, double[] reference, bool[] maximization, bool dominateOnEqualQualities) {
[13988]50      List<double[]> front = new List<double[]>();
51      foreach (double[] vec in qualities) {
52        if (Dominates(vec, reference, maximization, dominateOnEqualQualities) == DominationResult.Dominates) {
53          front.Add(vec);
[13562]54        }
[13988]55      }
56      return front;
57    }
[13562]58
[14018]59    public static DominationResult Dominates(double[] left, double[] right, bool[] maximizations, bool dominateOnEqualQualities) {
[13988]60      //mkommend Caution: do not use LINQ.SequenceEqual for comparing the two quality arrays (left and right) due to performance reasons
61      if (dominateOnEqualQualities) {
62        var equal = true;
63        for (int i = 0; i < left.Length; i++) {
64          if (left[i] != right[i]) {
65            equal = false;
66            break;
67          }
[13936]68        }
[13988]69        if (equal) return DominationResult.Dominates;
70      }
[13562]71
[13988]72      bool leftIsBetter = false, rightIsBetter = false;
73      for (int i = 0; i < left.Length; i++) {
74        if (IsDominated(left[i], right[i], maximizations[i])) rightIsBetter = true;
75        else if (IsDominated(right[i], left[i], maximizations[i])) leftIsBetter = true;
76        if (leftIsBetter && rightIsBetter) break;
77      }
[13562]78
[13988]79      if (leftIsBetter && !rightIsBetter) return DominationResult.Dominates;
80      if (!leftIsBetter && rightIsBetter) return DominationResult.IsDominated;
81      return DominationResult.IsNonDominated;
[13562]82    }
[13988]83
84    private static bool IsDominated(double left, double right, bool maximization) {
85      return maximization && left < right
86        || !maximization && left > right;
87    }
88
89  }
[13562]90}
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