ec.parsimony

Class ProportionalTournamentSelection

java.lang.Object

ec.BreedingSource

ec.SelectionMethod

ec.select.TournamentSelection

ec.parsimony.ProportionalTournamentSelection

All Implemented Interfaces:

Prototype, Setup, SteadyStateBSourceForm, RandomChoiceChooserD, Serializable, Cloneable

public class ProportionalTournamentSelection
extends TournamentSelection

This selection method adds parsimony pressure to the regular tournament selection. The comparison of individuals is based on fitness with probability prob, and it is based on size with probability 1-prob. For each pairwise comparsion of individuals, the ProportionalTournamentSelection randomly decides whether to compare based on fitness or size.

Typical Number of Individuals Produced Per produce(...) call
Always 1.

Parameters

base.size int >= 1	(the tournament size)
base.pick-worst bool = true or false (default)	(should we pick the worst individual in the tournament instead of the best?)
base.fitness-prob double >= 0 and <= 1	(the probability of comparing individuals based on fitness, rather than size)

Default Base
select.proportional-tournament

Version:

1.0

Author:

Liviu Panait

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
double	fitnessPressureProb The probability of having the tournament based on fitness
static String	P_PROBABILITY The parameter for the probability of having the tournament based on fitness
static String	P_PROPORTIONAL_TOURNAMENT default base

Fields inherited from class ec.select.TournamentSelection

P_PICKWORST, P_SIZE, P_TOURNAMENT, pickWorst, probabilityOfPickingSizePlusOne

Fields inherited from class ec.SelectionMethod

INDS_PRODUCED

Fields inherited from class ec.BreedingSource

NO_PROBABILITY, P_PROB, probability

Constructor Summary

Constructors

Constructor and Description
ProportionalTournamentSelection()

Method Summary

Methods

Modifier and Type	Method and Description
boolean	betterThan(Individual first, Individual second, int subpopulation, EvolutionState state, int thread) Returns true if *first* is a better (fitter, whatever) individual than *second*.
Parameter	defaultBase() Returns the default base for this prototype.
void	setup(EvolutionState state, Parameter base) Sets up the BreedingPipeline.

Methods inherited from class ec.select.TournamentSelection

getRandomIndividual, getTournamentSizeToUse, individualReplaced, produce, sourcesAreProperForm

Methods inherited from class ec.SelectionMethod

finishProducing, prepareToProduce, produce, produces, typicalIndsProduced

Methods inherited from class ec.BreedingSource

clone, getProbability, pickRandom, preparePipeline, setProbability, setupProbabilities

Methods inherited from class java.lang.Object

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

Field Detail

P_PROPORTIONAL_TOURNAMENT

public static final String P_PROPORTIONAL_TOURNAMENT

default base

See Also:

Constant Field Values

P_PROBABILITY

public static final String P_PROBABILITY

The parameter for the probability of having the tournament based on fitness

See Also:

Constant Field Values

fitnessPressureProb

public double fitnessPressureProb

The probability of having the tournament based on fitness

Constructor Detail

ProportionalTournamentSelection

public ProportionalTournamentSelection()

Method Detail

defaultBase

public Parameter defaultBase()

Description copied from interface: Prototype

Returns the default base for this prototype. This should generally be implemented by building off of the static base() method on the DefaultsForm object for the prototype's package. This should be callable during setup(...).

Specified by:

defaultBase in interface Prototype

Overrides:

defaultBase in class TournamentSelection

setup

public void setup(EvolutionState state,
         Parameter base)

Description copied from class: BreedingSource

Sets up the BreedingPipeline. You can use state.output.error here because the top-level caller promises to call exitIfErrors() after calling setup. Note that probability might get modified again by an external source if it doesn't normalize right.

The most common modification is to normalize it with some other set of probabilities, then set all of them up in increasing summation; this allows the use of the fast static BreedingSource-picking utility method, BreedingSource.pickRandom(...). In order to use this method, for example, if four breeding source probabilities are {0.3, 0.2, 0.1, 0.4}, then they should get normalized and summed by the outside owners as: {0.3, 0.5, 0.6, 1.0}.

Specified by:

setup in interface Prototype

Specified by:

setup in interface Setup

Overrides:

setup in class TournamentSelection

See Also:

Prototype.setup(EvolutionState,Parameter)

betterThan

public boolean betterThan(Individual first,
                 Individual second,
                 int subpopulation,
                 EvolutionState state,
                 int thread)

Description copied from class: TournamentSelection

Returns true if *first* is a better (fitter, whatever) individual than *second*.

Overrides:

betterThan in class TournamentSelection