source: src/main/java/genius/core/utility/AdditiveUtilitySpaceWithPerturbation.java

package genius.core.utility;

import java.util.Enumeration;

import genius.core.Bid;
import genius.core.issue.Objective;

/* Created by Dimitrios Tsimpoukis
 * 
 * Subclass of AdditiveUtilitySpace that adds a perturbation in the utility of the bids.
 * Used for the introduction of Uncertainty. Only changed method is getUtility(Bid bid)
 *
 *
 */

public class AdditiveUtilitySpaceWithPerturbation extends AdditiveUtilitySpace {

        private static final long serialVersionUID = -8882680929008252676L;

        private double perturbation;

        public AdditiveUtilitySpaceWithPerturbation(AdditiveUtilitySpace uspace) {
                super(uspace);
        }

        public AdditiveUtilitySpaceWithPerturbation(AdditiveUtilitySpace uspace,
                        double perturbation) {
                super(uspace);
                this.perturbation = perturbation;
        }

        @Override
        public double getUtility(Bid bid) {
                double utility = 0;

                Objective root = getDomain().getObjectivesRoot();
                Enumeration<Objective> issueEnum = root.getPreorderIssueEnumeration();
                while (issueEnum.hasMoreElements()) {
                        Objective is = issueEnum.nextElement();
                        Evaluator eval = getEvaluator(is);
                        if (eval == null) {
                                throw new IllegalArgumentException(
                                                "UtilitySpace does not contain evaluator for issue "
                                                                + is + ". ");
                        }

                        switch (eval.getType()) {
                        case DISCRETE:
                        case INTEGER:
                        case REAL:
                                utility += eval.getWeight()
                                                * getEvaluation(is.getNumber(), bid);
                                break;
                        case OBJECTIVE:
                                // we ignore OBJECTIVE. Not clear what it is and why.
                                break;
                        }
                }
                double result = utility + perturbation; // Introduction of Perturbation
                if (result > 1)
                        return 1;
                if (result < 0)
                        return 0;
                return result;
        }

        public double getPerturbation() {
                return perturbation;
        }

        public void setPerturbation(double perturbation) {
                this.perturbation = perturbation;
        }

}