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source: trunk/sources/HeuristicLab.Optimization.Operators/3.3/WeightedParentsQualityComparator.cs @ 3868

Last change on this file since 3868 was 3868, checked in by abeham, 13 years ago

#1022

  • Changed WeightedParentsQualityComparator to allow ComparisonFactor values smaller than 0 or greater than 1
File size: 5.8 KB
Line 
1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2010 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
22using System;
23using System.Collections.Generic;
24using System.Linq;
25using HeuristicLab.Core;
26using HeuristicLab.Data;
27using HeuristicLab.Operators;
28using HeuristicLab.Parameters;
29using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
30
31namespace HeuristicLab.Optimization.Operators {
32  [Item("WeightedParentsQualityComparator", "Compares the quality against that of its parents (assumes the parents are subscopes to the child scope). This operator works with any number of subscopes > 0.")]
33  [StorableClass]
34  public class WeightedParentsQualityComparator : SingleSuccessorOperator, ISubScopesQualityComparator {
35    public IValueLookupParameter<BoolValue> MaximizationParameter {
36      get { return (IValueLookupParameter<BoolValue>)Parameters["Maximization"]; }
37    }
38    public ILookupParameter<DoubleValue> LeftSideParameter {
39      get { return (ILookupParameter<DoubleValue>)Parameters["LeftSide"]; }
40    }
41    public ILookupParameter<ItemArray<DoubleValue>> RightSideParameter {
42      get { return (ILookupParameter<ItemArray<DoubleValue>>)Parameters["RightSide"]; }
43    }
44    public ILookupParameter<BoolValue> ResultParameter {
45      get { return (ILookupParameter<BoolValue>)Parameters["Result"]; }
46    }
47    public ValueLookupParameter<DoubleValue> ComparisonFactorParameter {
48      get { return (ValueLookupParameter<DoubleValue>)Parameters["ComparisonFactor"]; }
49    }
50
51    public WeightedParentsQualityComparator()
52      : base() {
53      Parameters.Add(new ValueLookupParameter<BoolValue>("Maximization", "True if the problem is a maximization problem, false otherwise"));
54      Parameters.Add(new LookupParameter<DoubleValue>("LeftSide", "The quality of the child."));
55      Parameters.Add(new ScopeTreeLookupParameter<DoubleValue>("RightSide", "The qualities of the parents."));
56      Parameters.Add(new LookupParameter<BoolValue>("Result", "The result of the comparison: True means Quality is better, False means it is worse than parents."));
57      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."));
58    }
59
60    public override IOperation Apply() {
61      ItemArray<DoubleValue> rightQualities = RightSideParameter.ActualValue;
62      if (rightQualities.Length < 1) throw new InvalidOperationException(Name + ": No subscopes found.");
63      double compFact = ComparisonFactorParameter.ActualValue.Value;
64      bool maximization = MaximizationParameter.ActualValue.Value;
65      double leftQuality = LeftSideParameter.ActualValue.Value;
66
67      double threshold = 0;
68
69      #region Calculate threshold
70      if (rightQualities.Length == 2) { // this case will probably be used most often
71        double minQuality = Math.Min(rightQualities[0].Value, rightQualities[1].Value);
72        double maxQuality = Math.Max(rightQualities[0].Value, rightQualities[1].Value);
73        if (maximization)
74          threshold = minQuality + (maxQuality - minQuality) * compFact;
75        else
76          threshold = maxQuality - (maxQuality - minQuality) * compFact;
77      } else if (rightQualities.Length == 1) { // case for just one parent
78        threshold = rightQualities[0].Value;
79      } else { // general case extended to 3 or more parents
80        List<double> sortedQualities = rightQualities.Select(x => x.Value).ToList();
81        sortedQualities.Sort();
82        double minimumQuality = sortedQualities.First();
83
84        double integral = 0;
85        for (int i = 0; i < sortedQualities.Count - 1; i++) {
86          integral += (sortedQualities[i] + sortedQualities[i + 1]) / 2.0; // sum of the trapezoid
87        }
88        integral -= minimumQuality * sortedQualities.Count;
89        if (integral == 0) threshold = sortedQualities[0]; // all qualities are equal
90        else {
91          double selectedArea = integral * (maximization ? compFact : (1 - compFact));
92          integral = 0;
93          for (int i = 0; i < sortedQualities.Count - 1; i++) {
94            double currentSliceArea = (sortedQualities[i] + sortedQualities[i + 1]) / 2.0;
95            double windowedSliceArea = currentSliceArea - minimumQuality;
96            if (windowedSliceArea == 0) continue;
97            integral += windowedSliceArea;
98            if (integral >= selectedArea) {
99              double factor = 1 - ((integral - selectedArea) / (windowedSliceArea));
100              threshold = sortedQualities[i] + (sortedQualities[i + 1] - sortedQualities[i]) * factor;
101              break;
102            }
103          }
104        }
105      }
106      #endregion
107
108      bool result = maximization && leftQuality > threshold || !maximization && leftQuality < threshold;
109      BoolValue resultValue = ResultParameter.ActualValue;
110      if (resultValue == null) {
111        ResultParameter.ActualValue = new BoolValue(result);
112      } else {
113        resultValue.Value = result;
114      }
115
116      return base.Apply();
117    }
118  }
119}
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