source: src/main/java/negotiator/parties/CustomUtilitySpaceExampleParty.java@ 167

package negotiator.parties;

import java.util.List;

import genius.core.Bid;
import genius.core.Domain;
import genius.core.actions.Action;
import genius.core.actions.Offer;
import genius.core.parties.AbstractNegotiationParty;
import genius.core.parties.NegotiationInfo;
import genius.core.uncertainty.BidRanking;
import genius.core.uncertainty.ExperimentalUserModel;
import genius.core.utility.AbstractUtilitySpace;
import genius.core.utility.CustomUtilitySpace;

/**
 * Example of a party that deals with preference uncertainty by defining a custom UtilitySpace 
 * based on the closest known bid.
 * 
 * Given a bid b and a preference ranking o1 <= o2 <= ... < on from the user model, it does the following:
 * It finds the outcome oi that is 'most similar' to b (in terms of overlapping values)
 * It then estimates u(b) to be: (i / n)  * (highestUtil - lowestUtil) 
 * 
 * Note that this agent's estimate of the utility function is not linear additive.
 */
public class CustomUtilitySpaceExampleParty extends AbstractNegotiationParty 
{
        
        @Override
        public void init(NegotiationInfo info) 
        {
                super.init(info);
                log("This is an example of a party that deals with preference uncertainty by defining with a Custom UtilitySpace estimate.");
                log("The user model is: " + userModel);
                if (userModel == null)
                {
                        log("There is no preference uncertainty. Try this agent with a negotiation scenario that has preference uncertainty enabled.");
                        return;
                }
                
                log("Lowest util: " + userModel.getBidRanking().getLowUtility() 
            + ". Highest util: " + userModel.getBidRanking().getHighUtility());
                log("The estimated utility space is: " + getUtilitySpace());

                Bid randomBid = getUtilitySpace().getDomain().getRandomBid(rand);
                log("The estimate of the utility of a random bid (" + randomBid + ") is: " + getUtility(randomBid));

                if (userModel instanceof ExperimentalUserModel) 
                {
                        log("You have given the agent access to the real utility space for debugging purposes.");
                        ExperimentalUserModel e = (ExperimentalUserModel) userModel;
                        AbstractUtilitySpace realUSpace = e.getRealUtilitySpace();

                        log("The real utility space is: " + realUSpace);
                        log("The real utility of the random bid is: "
                                        + realUSpace.getUtility(randomBid));
                }
        }

        /**
         * A simple concession function over time
         */
        @Override
        public Action chooseAction(List<Class<? extends Action>> possibleActions) 
        {
                double target = 1;
                // Return a random, conceding offer
                Bid randomBid;
                do
                {
                        randomBid = generateRandomBid();
                        target *= 0.999; 
                }
                while (getUtility(randomBid) < target);
                return new Offer(getPartyId(), randomBid);
        }

        /**
         * We override the default estimate of the utility
         * space by using {@link ClosestKnownBid} defined below.
         */
        @Override
        public AbstractUtilitySpace estimateUtilitySpace() 
        {
                return new ClosestKnownBid(getDomain());
        }

        @Override
        public String getDescription() {
                return "Example agent with a custom utility space";
        }
        
        private class ClosestKnownBid extends CustomUtilitySpace
        {

                public ClosestKnownBid(Domain dom) {
                        super(dom);
                }

                @Override
                public double getUtility(Bid bid) 
                {
                        Bid closestRankedBid = getClosestBidRanked(bid);
                        System.out.println("Closest bid: " + closestRankedBid);
                        return estimateUtilityOfRankedBid(closestRankedBid);
                }
                
                public double estimateUtilityOfRankedBid(Bid b)
                {
                        BidRanking bidRanking = getUserModel().getBidRanking();
                        int i = bidRanking.indexOf(b);
                        
                        System.out.println("Index: " + i);
                        // index:0 has utility 0, index n-1 has utility 1
                        return i / (double) bidRanking.getSize();
                }
                
                /**
                 * Finds the bid in the bid ranking that is most similar to bid given in the argument bid
                 */
                public Bid getClosestBidRanked(Bid bid)
                {
                        List<Bid> bidOrder = getUserModel().getBidRanking().getBidOrder();
                        Bid closestBid = null;
                        double closestDistance = Double.MAX_VALUE;
                                
                        for (Bid b : bidOrder)
                        {
                                double d = 1 / (double) b.countEqualValues(bid);
                                if (d < closestDistance)
                                {
                                        closestDistance = d;
                                        closestBid = b;
                                }
                        }
                        return closestBid;
                }
                
        }
        
        private static void log(String s) 
        {
                System.out.println(s);
        }

}