Package 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<Object>
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:

  • Field Details

    • SPEA2_FITNESS_PREAMBLE

      public static final String SPEA2_FITNESS_PREAMBLE
      See Also:

    • SPEA2_STRENGTH_PREAMBLE

      public static final String SPEA2_STRENGTH_PREAMBLE
      See Also:

    • SPEA2_DISTANCE_PREAMBLE

      public static final String SPEA2_DISTANCE_PREAMBLE
      See Also:

    • 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 Details

    • SPEA2MultiObjectiveFitness

      public SPEA2MultiObjectiveFitness()

  • Method Details

    • 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