com.epochx.op.selection
Class TournamentSelector<TYPE>

java.lang.Object
  com.epochx.op.selection.TournamentSelector<TYPE>

All Implemented Interfaces:

PoolSelector<TYPE>, ProgramSelector<TYPE>

public class TournamentSelector<TYPE>
extends java.lang.Object
implements ProgramSelector<TYPE>, PoolSelector<TYPE>

Tournament selection provides both program and pool selection. In tournament selection, x programs are randomly selected from the population to enter a 'tournament'. The program with the best fitness in the tournament then becomes the selected program. The tournament size, x, is given as an argument to the constructor.

Constructor Summary

TournamentSelector(GPModel<TYPE> model, int tournamentSize)
Construct a tournament selector with the specified tournament size.

Method Summary

java.util.List<CandidateProgram<TYPE>>	getPool(java.util.List<CandidateProgram<TYPE>> pop, int poolSize) Constructs a pool of programs from the population, choosing each one with the program selection element of TournamentSelector.
CandidateProgram<TYPE>	getProgram() Randomly creates a tournament, then selects the candidate program with the best fitness from that tournament.
void	setSelectionPool(java.util.List<CandidateProgram<TYPE>> pop) Store the population for creating tournaments from.

Methods inherited from class java.lang.Object

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

Constructor Detail

TournamentSelector

public TournamentSelector(GPModel<TYPE> model,
                          int tournamentSize)

Construct a tournament selector with the specified tournament size.

Parameters:

tournamentSize - the number of programs in each tournament.

Method Detail

setSelectionPool

public void setSelectionPool(java.util.List<CandidateProgram<TYPE>> pop)

Store the population for creating tournaments from.

Specified by:

setSelectionPool in interface ProgramSelector<TYPE>

Parameters:

pop - the current population for this generation.

getProgram

public CandidateProgram<TYPE> getProgram()

Randomly creates a tournament, then selects the candidate program with the best fitness from that tournament. The size of the tournament is given at instantiation.

Specified by:

getProgram in interface ProgramSelector<TYPE>

Returns:

the best program from a randomly generated tournament.

getPool

public java.util.List<CandidateProgram<TYPE>> getPool(java.util.List<CandidateProgram<TYPE>> pop,
                                                      int poolSize)

Constructs a pool of programs from the population, choosing each one with the program selection element of TournamentSelector. The size of the pool created will be equal to the poolSize argument. The generated pool may contain duplicate programs, and as such the pool size may be greater than the population size.

Specified by:

getPool in interface PoolSelector<TYPE>

Parameters:

pop - the population of CandidatePrograms from which the programs in the pool should be chosen.

poolSize - the number of programs that should be selected from the population to form the pool. If poolSize is zero or less then no selection takes place and the given population is returned unaltered.

Returns:

the pool of candidate programs selected using tournament selection.