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source: branches/OKBJavaConnector/ECJClient/src/ec/multiobjective/spea2/SPEA2MultiObjectiveFitness.java @ 6152

Last change on this file since 6152 was 6152, checked in by bfarka, 13 years ago

added ecj and custom statistics to communicate with the okb services #1441

File size: 3.8 KB
Line 
1/*
2  Portions copyright 2010 by Sean Luke, Robert Hubley, and George Mason University
3  Licensed under the Academic Free License version 3.0
4  See the file "LICENSE" for more information
5*/
6
7package ec.multiobjective.spea2;
8
9import java.io.*;
10import ec.util.*;
11import ec.multiobjective.*;
12import ec.*;
13
14/*
15 * SPEA2MultiObjectiveFitness.java
16 *
17 * Created: Sat Oct 16 11:24:43 EDT 2010
18 * By: Sean Luke
19 * Replaces earlier class by: Robert Hubley, with revisions by Gabriel Balan and Keith Sullivan
20 */
21
22/**
23 * SPEA2MultiObjectiveFitness is a subclass of MultiObjectiveFitness which adds three auxiliary fitness
24 * measures used in SPEA2: strength S(i), kthNNDistance D(i), and a final fitness value R(i) + D(i). 
25 * Note that so-called "raw fitness" (what Sean calls "Wimpiness" in Essentials of Metaheuristics) is
26 * not retained.
27 *
28 * <p>The fitness comparison operators solely use the 'fitness' value R(i) + D(i).
29 */
30
31public class SPEA2MultiObjectiveFitness extends MultiObjectiveFitness
32    {
33    public static final String SPEA2_FITNESS_PREAMBLE = "Fitness: ";
34    public static final String SPEA2_STRENGTH_PREAMBLE = "Strength: ";
35    public static final String SPEA2_DISTANCE_PREAMBLE = "Distance: ";
36
37    public String[] getAuxilliaryFitnessNames() { return new String[] { "Strength", "Raw Fitness", "Kth NN Distance" }; }
38    public double[] getAuxilliaryFitnessValues() { return new double[] { strength, fitness, kthNNDistance }; }
39       
40    /** SPEA2 strength (# of nodes it dominates) */
41    public double strength; // S(i)
42
43    /** SPEA2 NN distance */
44    public double kthNNDistance; // D(i)
45
46    /** Final SPEA2 fitness.  Equals the raw fitness R(i) plus the kthNNDistance D(i). */
47    public double fitness;
48
49    public String fitnessToString()
50        {
51        return super.fitnessToString() + "\n" + SPEA2_FITNESS_PREAMBLE + Code.encode(fitness) + "\n" + SPEA2_STRENGTH_PREAMBLE + Code.encode(strength) + "\n" + SPEA2_DISTANCE_PREAMBLE + Code.encode(kthNNDistance);
52        }
53
54    public String fitnessToStringForHumans()
55        {
56        return super.fitnessToStringForHumans() + "\n" + "S=" + strength + " D=" + kthNNDistance + " " + SPEA2_FITNESS_PREAMBLE + fitness;
57        }
58
59    public void readFitness(final EvolutionState state, final LineNumberReader reader) throws IOException
60        {
61        super.readFitness(state, reader);
62        fitness = Code.readDoubleWithPreamble(SPEA2_FITNESS_PREAMBLE, state, reader);
63        strength = Code.readDoubleWithPreamble(SPEA2_STRENGTH_PREAMBLE, state, reader);
64        kthNNDistance = Code.readDoubleWithPreamble(SPEA2_DISTANCE_PREAMBLE, state, reader);
65        }
66
67    public void writeFitness(final EvolutionState state, final DataOutput dataOutput) throws IOException
68        {
69        super.writeFitness(state, dataOutput);
70        dataOutput.writeDouble(fitness);
71        dataOutput.writeDouble(strength);
72        dataOutput.writeDouble(fitness);
73        dataOutput.writeDouble(kthNNDistance);
74        }
75
76    public void readFitness(final EvolutionState state, final DataInput dataInput) throws IOException
77        {
78        super.readFitness(state, dataInput);
79        fitness = dataInput.readDouble();
80        strength = dataInput.readDouble();
81        fitness = dataInput.readDouble();
82        kthNNDistance = dataInput.readDouble();
83        }
84
85    /**
86     * The selection criteria in SPEA2 uses the computed fitness, and not
87     * pareto dominance.
88     */
89    public boolean equivalentTo(Fitness _fitness)
90        {
91        return fitness == ((SPEA2MultiObjectiveFitness)_fitness).fitness;
92        }
93
94    /**
95     * The selection criteria in SPEA2 uses the computed fitness, and not
96     * pareto dominance.
97     */
98    public boolean betterThan(Fitness _fitness)
99        {
100        return fitness < ((SPEA2MultiObjectiveFitness)_fitness).fitness;
101        }
102    }
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