source: java/ecj/cecj/app/numbers_game/SingleDimensionalNumbersGame.java @ 101

package cecj.app.numbers_game;

import java.math.BigDecimal;
import java.math.RoundingMode;

import cecj.interaction.InteractionResult;
import cecj.interaction.RealValuedResult;
import cecj.problems.SymmetricTestBasedProblem;
import cecj.statistics.ObjectiveFitnessCalculator;
import cecj.utils.Pair;

import ec.EvolutionState;
import ec.Individual;
import ec.vector.BitVectorIndividual;

public class SingleDimensionalNumbersGame extends SymmetricTestBasedProblem implements ObjectiveFitnessCalculator {

        @Override
        public Pair<? extends InteractionResult> test(EvolutionState state, Individual candidate,
                        Individual test) {
                if (!(candidate instanceof BitVectorIndividual) || !(test instanceof BitVectorIndividual)) {
                        state.output.error("Competitor individuals should be represented by bit vectors\n");
                }

                BitVectorIndividual bitCandidate = (BitVectorIndividual) candidate;
                BitVectorIndividual bitTest = (BitVectorIndividual) test;

                if (bitCandidate.genomeLength() != bitTest.genomeLength()) {
                        state.output.error("Competitors' bit vectors should be equal length\n");
                }

                for (int i = 0; i < bitCandidate.genomeLength(); i++) {
                        if (bitCandidate.genome[i] != bitTest.genome[i]) {
                                if (bitCandidate.genome[i]) {
                                        return new Pair<RealValuedResult>(new RealValuedResult(1),
                                                new RealValuedResult(0));
                                } else {
                                        return new Pair<RealValuedResult>(new RealValuedResult(0),
                                                new RealValuedResult(1));
                                }
                        }
                }

                return new Pair<RealValuedResult>(new RealValuedResult(0), new RealValuedResult(0));
        }

        public float calculateObjectiveFitness(EvolutionState state, Individual ind) {
                if (!(ind instanceof BitVectorIndividual)) {
                        state.output.error("Competitor individuals should be represented by bit vectors\n");
                }
                BitVectorIndividual bitIndividual = (BitVectorIndividual) ind;

                BigDecimal two = new BigDecimal(2);
                BigDecimal maxValue = two.pow(bitIndividual.genome.length).subtract(BigDecimal.ONE);

                BigDecimal result = BigDecimal.ZERO;
                for (int i = 0; i < bitIndividual.genomeLength(); i++) {
                        result = result.multiply(two);
                        if (bitIndividual.genome[i]) {
                                result = result.add(BigDecimal.ONE);
                        }
                }

                return result.divide(maxValue, 10, RoundingMode.DOWN).floatValue();
        }

        @Deprecated
        public float calculateLongObjectiveFitness(EvolutionState state, Individual ind) {
                if (!(ind instanceof BitVectorIndividual)) {
                        state.output.error("Competitor individuals should be represented by bit vectors\n");
                }

                BitVectorIndividual bitIndividual = (BitVectorIndividual) ind;
                long result = 0;
                for (int i = 0; i < bitIndividual.genomeLength(); i++) {
                        result *= 2;
                        if (bitIndividual.genome[i]) {
                                result++;
                        }
                }
                return result;
        }
}