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source: trunk/sources/HeuristicLab.Optimization.Operators/3.3/WeightedParentsQualityComparator.cs @ 3659

Last change on this file since 3659 was 3659, checked in by swagner, 14 years ago

Worked on refactoring of algorithm analysis and tracing (#999)

  • removed SubScopesSubScopesLookupParameter
  • adapted SubScopesLookupParameter and renamed it into ScopeTreeLookupParameter
File size: 5.9 KB
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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      if (compFact < 0 || compFact > 1) throw new InvalidOperationException(Name + ": Comparison Factor is outside the range [0;1]");
65      bool maximization = MaximizationParameter.ActualValue.Value;
66      double leftQuality = LeftSideParameter.ActualValue.Value;
67
68      double threshold = 0;
69
70      #region Calculate threshold
71      if (rightQualities.Length == 2) { // this case will probably be used most often
72        threshold = (maximization ?
73        (Math.Max(rightQualities[0].Value, rightQualities[1].Value) * compFact + Math.Min(rightQualities[0].Value, rightQualities[1].Value) * (1 - compFact)) :
74        (Math.Min(rightQualities[0].Value, rightQualities[1].Value) * compFact + Math.Max(rightQualities[0].Value, rightQualities[1].Value) * (1 - compFact)));
75      } else if (rightQualities.Length == 1) { // case for just one parent
76        threshold = rightQualities[0].Value;
77      } else { // general case extended to 3 or more parents
78        List<double> sortedQualities = rightQualities.Select(x => x.Value).ToList();
79        sortedQualities.Sort();
80        double min = sortedQualities.First() * -1; // min is used to pull the qualities to the 0 line
81
82        double sum = min * sortedQualities.Count;
83        for (int i = 0; i < sortedQualities.Count - 1; i++) {
84          sum += (sortedQualities[i] + sortedQualities[i + 1]) / 2.0; // sum of the trapezoid
85        }
86        if (sum == 0) threshold = sortedQualities[0]; // all qualities are equal
87        else {
88          double area = sum * (maximization ? compFact : (1 - compFact)); // the qualities are sorted ascending so in minimization a high comp factor (close to 1) means small area
89          sum = 0;
90          for (int i = 0; i < sortedQualities.Count - 1; i++) {
91            double currentArea = (sortedQualities[i] + sortedQualities[i + 1]) / 2.0;
92            if (min + currentArea == 0) continue; // skip the first few consecutive 0s
93            sum += min + currentArea;
94            if (sum >= area) {
95              double factor = 1 - ((sum - area) / (min + currentArea));
96              threshold = sortedQualities[i] + (sortedQualities[i + 1] - sortedQualities[i]) * factor;
97              break;
98            }
99          }
100        }
101      }
102      #endregion
103
104      bool result = maximization && leftQuality > threshold || !maximization && leftQuality < threshold;
105      BoolValue resultValue = ResultParameter.ActualValue;
106      if (resultValue == null) {
107        ResultParameter.ActualValue = new BoolValue(result);
108      } else {
109        resultValue.Value = result;
110      }
111
112      return base.Apply();
113    }
114  }
115}
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