Package ec.select

Class TopSelection

java.lang.Object

ec.BreedingSource

ec.SelectionMethod

ec.select.TopSelection

All Implemented Interfaces:

Prototype, Setup, RandomChoiceChooserD, Serializable, Cloneable

public class TopSelection
extends SelectionMethod

Returns the single fittest individual in the population, breaking ties randomly.

The individual can be cached so it is not recomputed every single time; the cache is cleared after prepareToProduce(...) is called. Note that this means that if there are multiple individuals with the top fitness, and we're caching, only one of them will be returned throughout the series of multiple produce(...) calls.

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

Parameters

base.cache bool = true or false (default)

(should we cache the individual?)

Default Base
select.top

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static final String	P_CACHE
static final String	P_TOP	Default base

Fields inherited from class ec.SelectionMethod

INDS_PRODUCED, KEY_PARENTS

Fields inherited from class ec.BreedingSource

NO_PROBABILITY, P_PROB, probability

Constructor Summary

Constructors

Constructor	Description
TopSelection()

Method Summary

Modifier and Type	Method	Description
void	cacheBest(int subpopulation, EvolutionState state, int thread)
Parameter	defaultBase()	Returns the default base for this prototype.
void	prepareToProduce(EvolutionState s, int subpopulation, int thread)	A default version of prepareToProduce which does nothing.
int	produce(int subpopulation, EvolutionState state, int thread)	An alternative form of "produce" special to Selection Methods; selects an individual from the given subpopulation and returns its position in that subpopulation.
void	setup(EvolutionState state, Parameter base)	Sets up the BreedingPipeline.

Methods inherited from class ec.SelectionMethod

finishProducing, produce, produces, produceWithoutCloning, typicalIndsProduced

Methods inherited from class ec.BreedingSource

clone, fillStubs, getProbability, pickRandom, preparePipeline, setProbability, setupProbabilities

Methods inherited from class java.lang.Object

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

Field Details

P_TOP

public static final String P_TOP

Default base

See Also:

• Constant Field Values

P_CACHE

public static final String P_CACHE

See Also:

• Constant Field Values

Constructor Details

TopSelection

public TopSelection()

Method Details

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(...).

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 BreedingSource

See Also:

• Prototype.setup(EvolutionState,Parameter)

prepareToProduce

public void prepareToProduce(EvolutionState s,
 int subpopulation,
 int thread)

Description copied from class: SelectionMethod

A default version of prepareToProduce which does nothing.

Overrides:

prepareToProduce in class SelectionMethod

cacheBest

public void cacheBest(int subpopulation,
 EvolutionState state,
 int thread)

produce

public int produce(int subpopulation,
 EvolutionState state,
 int thread)

Description copied from class: SelectionMethod

An alternative form of "produce" special to Selection Methods; selects an individual from the given subpopulation and returns its position in that subpopulation.

Specified by:

produce in class SelectionMethod