ec.parsimony
Class ProportionalTournamentSelection

java.lang.Object
  extended by ec.BreedingSource
      extended by ec.SelectionMethod
          extended by ec.select.TournamentSelection
              extended by ec.parsimony.ProportionalTournamentSelection
All Implemented Interfaces:
Prototype, Setup, SteadyStateBSourceForm, RandomChoiceChooser, java.io.Serializable, java.lang.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

See Also:
Serialized Form

Field Summary
 double fitnessPressureProb
          The probability of having the tournament based on fitness
static java.lang.String P_PROBABILITY
          The parameter for the probability of having the tournament based on fitness
static java.lang.String P_PROPORTIONAL_TOURNAMENT
          default base
 
Fields inherited from class ec.select.TournamentSelection
DEFAULT_SIZE, 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
ProportionalTournamentSelection()
           
 
Method Summary
 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 java.lang.String P_PROPORTIONAL_TOURNAMENT
default base

See Also:
Constant Field Values

P_PROBABILITY

public static final java.lang.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