NeatSelectionPolicyHandler.java

package net.bmahe.genetics4j.neat.selection;

import java.util.random.RandomGenerator;

import org.apache.commons.lang3.Validate;

import org.apache.logging.log4j.LogManager;

import org.apache.logging.log4j.Logger;

import net.bmahe.genetics4j.core.selection.SelectionPolicyHandler;

import net.bmahe.genetics4j.core.selection.SelectionPolicyHandlerResolver;

import net.bmahe.genetics4j.core.selection.Selector;

import net.bmahe.genetics4j.core.spec.AbstractEAConfiguration;

import net.bmahe.genetics4j.core.spec.AbstractEAExecutionContext;

import net.bmahe.genetics4j.core.spec.selection.SelectionPolicy;

import net.bmahe.genetics4j.neat.SpeciesIdGenerator;

import net.bmahe.genetics4j.neat.spec.selection.NeatSelection;

/**

 * Selection policy handler for NEAT (NeuroEvolution of Augmenting Topologies) species-based selection.

 * 

 * <p>NeatSelectionPolicyHandler implements the species-based selection mechanism that is fundamental to the NEAT

 * algorithm. It organizes the population into species based on genetic compatibility, applies fitness sharing within

 * species, and manages reproduction allocation across species to maintain population diversity and protect innovative

 * topologies.

 * 

 * <p>Key responsibilities:

 * <ul>

 * <li><strong>Species formation</strong>: Groups genetically similar individuals into species</li>

 * <li><strong>Fitness sharing</strong>: Adjusts individual fitness based on species membership</li>

 * <li><strong>Reproduction allocation</strong>: Distributes offspring across species based on average fitness</li>

 * <li><strong>Diversity preservation</strong>: Protects innovative topologies from elimination by established

 * forms</li>

 * </ul>

 * 

 * <p>NEAT species-based selection process:

 * <ol>

 * <li><strong>Compatibility calculation</strong>: Measure genetic distance between individuals</li>

 * <li><strong>Species assignment</strong>: Assign individuals to species based on compatibility thresholds</li>

 * <li><strong>Fitness adjustment</strong>: Apply fitness sharing within each species</li>

 * <li><strong>Species evaluation</strong>: Calculate average fitness for each species</li>

 * <li><strong>Reproduction allocation</strong>: Determine offspring count for each species</li>

 * <li><strong>Within-species selection</strong>: Select parents within each species for reproduction</li>

 * </ol>

 * 

 * <p>Species management features:

 * <ul>

 * <li><strong>Dynamic speciation</strong>: Species boundaries adjust as population evolves</li>

 * <li><strong>Species extinction</strong>: Poor-performing species are eliminated</li>

 * <li><strong>Representative tracking</strong>: Maintains species representatives for compatibility testing</li>

 * <li><strong>Population diversity</strong>: Prevents single topology from dominating</li>

 * </ul>

 * 

 * <p>Common usage patterns:

 * 

 * <pre>{@code

 * // Create NEAT selection policy handler

 * RandomGenerator randomGen = RandomGenerator.getDefault();

 * SpeciesIdGenerator speciesIdGen = new SpeciesIdGenerator();

 * 

 * NeatSelectionPolicyHandler<Double> handler = new NeatSelectionPolicyHandler<>(randomGen, speciesIdGen);

 * 

 * // Configure NEAT selection policy

 * NeatSelection<Double> neatSelection = NeatSelection.<Double>builder()

 * 		.compatibilityThreshold(3.0)

 * 		.speciesSelection(new TournamentSelection(3)) // Within-species selection

 * 		.build();

 * 

 * // Resolve selector for EA execution

 * Selector<Double> selector = handler.resolve(executionContext, configuration, resolverRegistry, neatSelection);

 * }</pre>

 * 

 * <p>Integration with genetic operators:

 * <ul>

 * <li><strong>Crossover compatibility</strong>: Species ensure genetic compatibility for meaningful recombination</li>

 * <li><strong>Mutation guidance</strong>: Species composition influences structural mutation rates</li>

 * <li><strong>Innovation protection</strong>: New topologies get time to optimize within their species</li>

 * <li><strong>Diversity maintenance</strong>: Multiple species explore different regions of topology space</li>

 * </ul>

 * 

 * <p>Performance considerations:

 * <ul>

 * <li><strong>Compatibility caching</strong>: Genetic distances cached for efficiency</li>

 * <li><strong>Species reuse</strong>: Species structures maintained across generations</li>

 * <li><strong>Parallel processing</strong>: Species-based selection enables concurrent evaluation</li>

 * <li><strong>Memory management</strong>: Efficient species membership tracking</li>

 * </ul>

 * 

 * <p>Selection policy delegation:

 * <ul>

 * <li><strong>Within-species selection</strong>: Delegates to standard selection policies (tournament, roulette,

 * etc.)</li>

 * <li><strong>Composable policies</strong>: Can combine with any standard selection mechanism</li>

 * <li><strong>Flexible configuration</strong>: Different species can use different selection strategies</li>

 * <li><strong>Performance optimization</strong>: Leverages existing high-performance selectors</li>

 * </ul>

 * 

 * @param <T> the fitness value type (typically Double)

 * @see NeatSelection

 * @see NeatSelectorImpl

 * @see Species

 * @see SpeciesIdGenerator

 * @see SelectionPolicyHandler

 */

public class NeatSelectionPolicyHandler<T extends Number & Comparable<T>> implements SelectionPolicyHandler<T> {

	private final RandomGenerator randomGenerator;

	private final SpeciesIdGenerator speciesIdGenerator;

	/**

	 * Constructs a new NEAT selection policy handler with the specified components.

	 * 

	 * <p>The random generator is used for stochastic operations during species formation and selection. The species ID

	 * generator provides unique identifiers for newly created species throughout the evolutionary process.

	 * 

	 * @param _randomGenerator    random number generator for stochastic operations

	 * @param _speciesIdGenerator generator for unique species identifiers

	 * @throws IllegalArgumentException if randomGenerator or speciesIdGenerator is null

	 */

	public NeatSelectionPolicyHandler(final RandomGenerator _randomGenerator,

	/**

	 * Determines whether this handler can process the given selection policy.

	 * 

	 * <p>This handler specifically processes NeatSelection policies, which configure species-based selection with

	 * compatibility thresholds and within-species selection strategies.

	 * 

	 * @param selectionPolicy the selection policy to check

	 * @return true if the policy is a NeatSelection instance, false otherwise

	 * @throws IllegalArgumentException if selectionPolicy is null

	 */

	@Override

	public boolean canHandle(final SelectionPolicy selectionPolicy) {

	}

	/**

	 * Resolves a NEAT selection policy into a concrete selector implementation.

	 * 

	 * <p>This method creates a NeatSelectorImpl that implements the species-based selection mechanism. It resolves the

	 * within-species selection policy using the provided resolver and configures the selector with the necessary NEAT

	 * components.

	 * 

	 * <p>Resolution process:

	 * <ol>

	 * <li>Extract the within-species selection policy from the NEAT selection configuration</li>

	 * <li>Resolve the within-species selection policy to a concrete selector</li>

	 * <li>Create a NeatSelectorImpl with all necessary components</li>

	 * <li>Return the configured selector ready for use in evolution</li>

	 * </ol>

	 * 

	 * @param eaExecutionContext             the execution context for the evolutionary algorithm

	 * @param eaConfiguration                the configuration for the evolutionary algorithm

	 * @param selectionPolicyHandlerResolver resolver for nested selection policies

	 * @param selectionPolicy                the NEAT selection policy to resolve

	 * @return a configured selector implementing NEAT species-based selection

	 * @throws IllegalArgumentException if selectionPolicy is null or not a NeatSelection

	 */

	@Override

	public Selector<T> resolve(final AbstractEAExecutionContext<T> eaExecutionContext,

			final AbstractEAConfiguration<T> eaConfiguration,

			final SelectionPolicyHandlerResolver<T> selectionPolicyHandlerResolver,

			final SelectionPolicy selectionPolicy) {

	}

}

Mutations

1.1
Location : resolve
Killed by : none removed call to net/bmahe/genetics4j/neat/spec/selection/NeatSelection::speciesSelection → SURVIVED Covering tests