ec.multiobjective.spea2

Class SPEA2MultiObjectiveFitness

java.lang.Object

ec.Fitness

ec.multiobjective.MultiObjectiveFitness

ec.multiobjective.spea2.SPEA2MultiObjectiveFitness

All Implemented Interfaces:

Prototype, Setup, Serializable, Cloneable, Comparable

public class SPEA2MultiObjectiveFitness
extends MultiObjectiveFitness

SPEA2MultiObjectiveFitness is a subclass of MultiObjectiveFitness which adds three auxiliary fitness measures used in SPEA2: strength S(i), kthNNDistance D(i), and a final fitness value R(i) + D(i). Note that so-called "raw fitness" (what Sean calls "Wimpiness" in Essentials of Metaheuristics) is not retained.

The fitness comparison operators solely use the 'fitness' value R(i) + D(i).

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
double	fitness Final SPEA2 fitness.
double	kthNNDistance SPEA2 NN distance
static String	SPEA2_DISTANCE_PREAMBLE
static String	SPEA2_FITNESS_PREAMBLE
static String	SPEA2_STRENGTH_PREAMBLE
double	strength SPEA2 strength (# of nodes it dominates)

Fields inherited from class ec.multiobjective.MultiObjectiveFitness

FITNESS_POSTAMBLE, maximize, maxObjective, minObjective, MULTI_FITNESS_POSTAMBLE, objectives, P_MAXIMIZE, P_MAXOBJECTIVES, P_MINOBJECTIVES, P_NUMOBJECTIVES

Fields inherited from class ec.Fitness

context, FITNESS_PREAMBLE, P_FITNESS, trials

Constructor Summary

Constructors

Constructor and Description
SPEA2MultiObjectiveFitness()

Method Summary

Methods

Modifier and Type	Method and Description
boolean	betterThan(Fitness _fitness) The selection criteria in SPEA2 uses the computed fitness, and not pareto dominance.
boolean	equivalentTo(Fitness _fitness) The selection criteria in SPEA2 uses the computed fitness, and not pareto dominance.
String	fitnessToString() Print to a string the fitness in a fashion intended to be parsed in again via readFitness(...).
String	fitnessToStringForHumans() Print to a string the fitness in a fashion readable by humans, and not intended to be parsed in again.
String[]	getAuxilliaryFitnessNames() Returns auxilliary fitness value names to be printed by the statistics object.
double[]	getAuxilliaryFitnessValues() Returns auxilliary fitness values to be printed by the statistics object.
void	readFitness(EvolutionState state, DataInput dataInput) Reads the binary form of an individual from a DataInput.
void	readFitness(EvolutionState state, LineNumberReader reader) Reads in the fitness from a form outputted by fitnessToString() and thus printFitnessForHumans(...).
void	writeFitness(EvolutionState state, DataOutput dataOutput) Writes the binary form of an individual out to a DataOutput.

Methods inherited from class ec.multiobjective.MultiObjectiveFitness

clone, defaultBase, fitness, getNumObjectives, getObjective, getObjectives, getRankings, isIdealFitness, isMaximizing, isMaximizing, manhattanObjectiveDistance, paretoDominates, partitionIntoParetoFront, partitionIntoRanks, setObjectives, setToBestOf, setToMeanOf, setToMedianOf, setup, sumSquaredObjectiveDistance

Methods inherited from class ec.Fitness

compareTo, contextIsBetterThan, getContext, merge, printFitness, printFitness, printFitness, printFitnessForHumans, printFitnessForHumans, readTrials, setContext, setContext, writeTrials

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

SPEA2_FITNESS_PREAMBLE

public static final String SPEA2_FITNESS_PREAMBLE

See Also:

Constant Field Values

SPEA2_STRENGTH_PREAMBLE

public static final String SPEA2_STRENGTH_PREAMBLE

See Also:

Constant Field Values

SPEA2_DISTANCE_PREAMBLE

public static final String SPEA2_DISTANCE_PREAMBLE

See Also:

Constant Field Values

strength

public double strength

SPEA2 strength (# of nodes it dominates)

kthNNDistance

public double kthNNDistance

SPEA2 NN distance

fitness

public double fitness

Final SPEA2 fitness. Equals the raw fitness R(i) plus the kthNNDistance D(i).

Constructor Detail

SPEA2MultiObjectiveFitness

public SPEA2MultiObjectiveFitness()

Method Detail

getAuxilliaryFitnessNames

public String[] getAuxilliaryFitnessNames()

Description copied from class: MultiObjectiveFitness

Returns auxilliary fitness value names to be printed by the statistics object. By default, an empty array is returned, but various algorithms may override this to provide additional columns.

Overrides:

getAuxilliaryFitnessNames in class MultiObjectiveFitness

getAuxilliaryFitnessValues

public double[] getAuxilliaryFitnessValues()

Description copied from class: MultiObjectiveFitness

Returns auxilliary fitness values to be printed by the statistics object. By default, an empty array is returned, but various algorithms may override this to provide additional columns.

Overrides:

getAuxilliaryFitnessValues in class MultiObjectiveFitness

fitnessToString

public String fitnessToString()

Description copied from class: Fitness

Print to a string the fitness in a fashion intended to be parsed in again via readFitness(...). The fitness and evaluated flag should not be included. The default form simply calls toString(), which is almost certainly wrong, and you'll probably want to override this to something else. When overriding, you may wish to check to see if the 'trials' variable is non-null, and issue an error if so.

Overrides:

fitnessToString in class MultiObjectiveFitness

fitnessToStringForHumans

public String fitnessToStringForHumans()

Description copied from class: Fitness

Print to a string the fitness in a fashion readable by humans, and not intended to be parsed in again. The default form simply calls toString(), but you'll probably want to override this to something else.

Overrides:

fitnessToStringForHumans in class MultiObjectiveFitness

readFitness

public void readFitness(EvolutionState state,
               LineNumberReader reader)
                 throws IOException

Description copied from class: Fitness

Reads in the fitness from a form outputted by fitnessToString() and thus printFitnessForHumans(...). The default version of this method exits the program with an "unimplemented" error.

Overrides:

readFitness in class MultiObjectiveFitness

Throws:

IOException

writeFitness

public void writeFitness(EvolutionState state,
                DataOutput dataOutput)
                  throws IOException

Description copied from class: Fitness

Writes the binary form of an individual out to a DataOutput. This is not for serialization: the object should only write out the data relevant to the object sufficient to rebuild it from a DataInput. The default version exits the program with an "unimplemented" error; you should override this, and be certain to also write the 'trials' variable as well.

Overrides:

writeFitness in class MultiObjectiveFitness

Throws:

IOException

readFitness

public void readFitness(EvolutionState state,
               DataInput dataInput)
                 throws IOException

Description copied from class: Fitness

Reads the binary form of an individual from a DataInput. This is not for serialization: the object should only read in the data written out via printIndividual(state,dataInput). The default version exits the program with an "unimplemented" error; you should override this, and be certain to also write the 'trials' variable as well.

Overrides:

readFitness in class MultiObjectiveFitness

Throws:

IOException

equivalentTo

public boolean equivalentTo(Fitness _fitness)

The selection criteria in SPEA2 uses the computed fitness, and not pareto dominance.

Overrides:

equivalentTo in class MultiObjectiveFitness

betterThan

public boolean betterThan(Fitness _fitness)

The selection criteria in SPEA2 uses the computed fitness, and not pareto dominance.

Overrides:

betterThan in class MultiObjectiveFitness