source: java/ecj/cecj/interaction/InterPopulationInteractionScheme.java @ 35

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;

public class InterPopulationInteractionScheme implements InteractionScheme {

        private static final String P_POP = "pop";
        private static final String P_SIZE = "subpops";

        /**
         * Number of subpopulations.
         */
        private int numSubpopulations;

        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;
                }

                Parameter popSizeParameter = new Parameter(P_POP).push(P_SIZE);
                numSubpopulations = state.parameters.getInt(popSizeParameter, null, 0);
                if (numSubpopulations <= 0) {
                        state.output.fatal("Population size must be > 0.\n", popSizeParameter);
                }
        }

        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;

                for (Individual competitor : competitors) {
                        List<InteractionResult> results = new ArrayList<InteractionResult>();

                        for (int subpop2 = 0; subpop2 < numSubpopulations; subpop2++) {
                                if (subpop2 == subpop) {
                                        continue;
                                }

                                List<Individual> curOpponents = opponents.get(subpop2);
                                for (Individual opponent : curOpponents) {
                                        results.add(problem.compete(state, competitor, opponent).first);
                                }
                        }

                        subpopulationResults.add(results);
                }

                return subpopulationResults;
        }
}