source: java/ecj/cecj/interaction/IntraPopulationInteractionScheme.java

package cecj.interaction;

import java.util.ArrayList;
import java.util.List;

import cecj.problems.SymmetricCompetitionProblem;

import ec.EvolutionState;
import ec.Individual;
import ec.util.Parameter;

/**
 * 
 * 
 * @author Marcin Szubert
 * 
 */
public class IntraPopulationInteractionScheme implements InteractionScheme {

        private SymmetricCompetitionProblem problem;

        public void setup(EvolutionState state, Parameter base) {
                if (!(state.evaluator.p_problem instanceof SymmetricCompetitionProblem)) {
                        state.output.fatal("Intrapopulation interactions need symmetric problem definition\n");
                } else {
                        problem = (SymmetricCompetitionProblem) state.evaluator.p_problem;
                }
        }

        public List<List<InteractionResult>> performInteractions(EvolutionState state, int subpop,
                        List<List<Individual>> opponents) {

                List<List<InteractionResult>> subpopulationResults = new ArrayList<List<InteractionResult>>();
                Individual[] competitors = state.population.subpops[subpop].individuals;
                List<Individual> curOpponents = opponents.get(subpop);

                for (Individual competitor : competitors) {
                        List<InteractionResult> results = new ArrayList<InteractionResult>();
                        for (Individual opponent : curOpponents) {
                                results.add(problem.compete(state, competitor, opponent).first);
                                results.add(problem.compete(state, opponent, competitor).second);
                        }
                        subpopulationResults.add(results);
                }

                return subpopulationResults;
        }
}