
Watchmaker Framework for Evolutionary Computation API (Version 0.7.1) 

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java.lang.Object org.uncommons.watchmaker.framework.selection.TournamentSelection
public class TournamentSelection
Selection strategy that picks a pair of candidates at random and then selects the fitter of the two candidates with probability p, where p is the configured selection probability (therefore the probability of the less fit candidate being selected is 1  p).
Constructor Summary  

TournamentSelection(NumberGenerator<Probability> selectionProbability)
Creates a tournament selection strategy that is controlled by the variable selection probability provided by the specified NumberGenerator . 

TournamentSelection(Probability selectionProbability)
Creates a tournament selection strategy with a fixed probability. 
Method Summary  


select(List<EvaluatedCandidate<S>> population,
boolean naturalFitnessScores,
int selectionSize,
Random rng)
Select the specified number of candidates from the population. 

String 
toString()

Methods inherited from class java.lang.Object 

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait 
Constructor Detail 

public TournamentSelection(NumberGenerator<Probability> selectionProbability)
NumberGenerator
.
selectionProbability
 A number generator that produces values in
the range 0.5 < p < 1. These values are used as the probability
of the fittest candidate being selected in any given tournament.public TournamentSelection(Probability selectionProbability)
selectionProbability
 The probability that the fitter of two randomly
chosen candidates will be selected. Since this is a probability it must be
between 0.0 and 1.0. This implementation adds the further restriction that
the probability must be greater than 0.5 since any lower value would favour
weaker candidates over strong ones, negating the "survival of the fittest"
aspect of the evolutionary algorithm.Method Detail 

public <S> List<S> select(List<EvaluatedCandidate<S>> population, boolean naturalFitnessScores, int selectionSize, Random rng)
SelectionStrategy
Select the specified number of candidates from the population. Implementations may assume that the population is sorted in descending order according to fitness (so the fittest individual is the first item in the list).
It is an error to call this method with an empty or null population.
select
in interface SelectionStrategy<Object>
S
 The type of evolved entity that we are selecting, a subtype of T.population
 The population from which to select.naturalFitnessScores
 Whether higher fitness values represent fitter
individuals or not.selectionSize
 The number of individual selections to make (not necessarily
the number of distinct candidates to select, since the same individual may
potentially be selected more than once).rng
 Source of randomness for stochastic selection strategies.
public String toString()
toString
in class Object

Watchmaker Framework for Evolutionary Computation API (Version 0.7.1) 

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