source: java/ecj/cecj/app/othello/OthelloPlayerFitnessCalculator.java @ 57

package cecj.app.othello;

import cecj.statistics.ObjectiveFitnessCalculator;
import ec.EvolutionState;
import ec.Individual;
import ec.util.Parameter;
import ec.vector.DoubleVectorIndividual;
import games.BoardGame;
import games.Player;
import games.scenarios.GameScenario;
import games.scenarios.RandomizedTwoPlayersGameScenario;

public abstract class OthelloPlayerFitnessCalculator implements ObjectiveFitnessCalculator {

        protected static final int WPC_LENGTH = 64;
        
        protected static final String P_EVALUATOR_RANDOMNESS = "evaluator-randomness";
        protected static final String P_EVALUATED_RANDOMNESS = "evaluated-randomness";

        private static final String P_PLAY_BOTH = "play-both";
        private static final String P_REPEATS = "repeats";

        protected double evaluatedRandomness;
        protected double evaluatorRandomness;
        private boolean playBoth;
        private int repeats;

        public void setup(EvolutionState state, Parameter base) {
                Parameter randomnessParam = base.push(P_EVALUATED_RANDOMNESS);
                evaluatedRandomness = state.parameters.getDoubleWithDefault(randomnessParam, null, 0);

                randomnessParam = base.push(P_EVALUATOR_RANDOMNESS);
                evaluatorRandomness = state.parameters.getDoubleWithDefault(randomnessParam, null, 0);

                Parameter repetitionsParam = base.push(P_REPEATS);
                repeats = state.parameters.getIntWithDefault(repetitionsParam, null, 1);

                Parameter playBothParam = base.push(P_PLAY_BOTH);
                playBoth = state.parameters.getBoolean(playBothParam, null, false);
        }

        public float calculateObjectiveFitness(EvolutionState state, Individual ind) {
                if (!(ind instanceof DoubleVectorIndividual)) {
                        state.output.error("Othello players should be represented by floats vectors\n");
                }

                double[] wpc1 = ((DoubleVectorIndividual) ind).genome;

                if (wpc1.length != WPC_LENGTH) {
                        state.output.error("Players WPC vectors length should be 64\n");
                }

                Player player1 = new OthelloPlayer(wpc1);
                Player player2 = getPlayer();
                BoardGame game = new OthelloGame(new OthelloBoard());

                GameScenario scenario1 = new RandomizedTwoPlayersGameScenario(state.random[0], new Player[] { player1,
                                player2 }, new double[] { evaluatedRandomness, evaluatorRandomness });
                GameScenario scenario2 = new RandomizedTwoPlayersGameScenario(state.random[0], new Player[] { player2,
                                player1 }, new double[] { evaluatorRandomness, evaluatedRandomness });

                float sum = 0;
                for (int r = 0; r < repeats; r++) {
                        game.reset();
                        sum += ((scenario1.play(game) > 0) ? 1 : 0);
                        if (playBoth) {
                                game.reset();
                                sum += ((scenario2.play(game) < 0) ? 1 : 0);
                        }
                }

                if (playBoth) {
                        return sum / (repeats * 2);
                } else {
                        return sum / repeats;
                }
        }

        protected abstract OthelloPlayer getPlayer();
}