source: src/main/java/agents/SimpleAgt2.java@ 126

package agents;

import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Random;

import genius.core.Agent;
import genius.core.Bid;
import genius.core.SupportedNegotiationSetting;
import genius.core.actions.Accept;
import genius.core.actions.Action;
import genius.core.actions.ActionWithBid;
import genius.core.actions.Offer;
import genius.core.issue.Issue;
import genius.core.issue.IssueDiscrete;
import genius.core.issue.IssueReal;
import genius.core.issue.Value;
import genius.core.issue.ValueReal;

/**
 * 
 * @author W.Pasman Some improvements over the standard SimpleAgent.
 * 
 */
public class SimpleAgt2 extends Agent {
        private Action actionOfPartner = null;
        private static final double MINIMUM_BID_UTILITY = 0.5;

        @Override
        public void ReceiveMessage(Action opponentAction) {
                actionOfPartner = opponentAction;
        }

        @Override
        public String getVersion() {
                return "3.1";
        }

        @Override
        public String getName() {
                return "Simple Agent v2";
        }

        @Override
        public Action chooseAction() {
                Action action = null;
                Bid partnerBid = null;
                try {
                        if (actionOfPartner == null)
                                action = chooseRandomBidAction(null); // this may throw NPE!!
                        if (actionOfPartner instanceof Offer) {
                                partnerBid = ((Offer) actionOfPartner).getBid();
                                double offeredutil = utilitySpace.getUtility(partnerBid);
                                double time = ((new Date()).getTime() - startTime.getTime())
                                                / (1000. * totalTime);
                                double P = Paccept(offeredutil, time);
                                if (P > Math.random())
                                        action = new Accept(this.getAgentID(), partnerBid);
                                else
                                        action = chooseRandomBidAction(
                                                        ((ActionWithBid) actionOfPartner).getBid());
                        }
                        sleep(0.005); // just for fun
                } catch (Exception e) {
                        System.out.println("Exception in ChooseAction:" + e.getMessage());
                        // best guess if things go
                        action = new Accept(this.getAgentID(), partnerBid);
                        // wrong.
                }
                return action;
        }

        /**
         * Wrapper for getRandomBid, for convenience.
         * 
         * @param lastOppBid
         *            the last opponent bid received.
         * @return new Action(Bid(..)), with bid utility > MINIMUM_BID_UTIL. If a
         *         problem occurs, it returns an Accept() action.
         * 
         */
        private Action chooseRandomBidAction(Bid lastOppBid) {
                Bid nextBid = null;
                try {
                        nextBid = getRandomBid();
                } catch (Exception e) {
                        System.out.println("Problem with received bid:" + e.getMessage()
                                        + ". cancelling bidding");
                }
                if (nextBid == null)
                        return (new Accept(this.getAgentID(), lastOppBid));
                return (new Offer(this.getAgentID(), nextBid));
        }

        /**
         * @return a random bid with high enough utility value.
         * @throws Exception
         *             if we can't compute the utility (eg no evaluators have been
         *             set) or when other evaluators than a DiscreteEvaluator are
         *             present in the util space.
         */
        private Bid getRandomBid() throws Exception {
                HashMap<Integer, Value> values = new HashMap<Integer, Value>(); // pairs
                                                                                                                                                // <issuenumber,chosen
                                                                                                                                                // value
                                                                                                                                                // string>
                List<Issue> issues = utilitySpace.getDomain().getIssues();
                Random randomnr = new Random();

                // createFrom a random bid with utility>MINIMUM_BID_UTIL.
                // note that this may never succeed if you set MINIMUM too high!!!
                // in that case we will search for a bid till the time is up (2 minutes)
                // but this is just a simple agent.
                Bid bid = null;
                do {
                        for (Issue lIssue : issues) {
                                switch (lIssue.getType()) {
                                case DISCRETE:
                                        IssueDiscrete lIssueDiscrete = (IssueDiscrete) lIssue;
                                        int optionIndex = randomnr
                                                        .nextInt(lIssueDiscrete.getNumberOfValues());
                                        values.put(lIssue.getNumber(),
                                                        lIssueDiscrete.getValue(optionIndex));
                                        break;
                                case REAL:
                                        IssueReal lIssueReal = (IssueReal) lIssue;
                                        int lNrOfOptions = lIssueReal
                                                        .getNumberOfDiscretizationSteps();
                                        double lOneStep = (lIssueReal.getUpperBound()
                                                        - lIssueReal.getLowerBound()) / lNrOfOptions;
                                        int lOptionIndex = Double
                                                        .valueOf(java.lang.Math.random() * (lNrOfOptions))
                                                        .intValue();
                                        if (lOptionIndex >= lNrOfOptions)
                                                lOptionIndex = lNrOfOptions - 1;
                                        values.put(lIssueReal.getNumber(),
                                                        new ValueReal(lIssueReal.getLowerBound()
                                                                        + lOneStep * lOptionIndex));
                                        break;

                                default:
                                        throw new Exception("issue type " + lIssue.getType()
                                                        + " not supported by SimpleAgent2");
                                }
                        }
                        bid = new Bid(utilitySpace.getDomain(), values);
                } while (utilitySpace.getUtility(bid) < MINIMUM_BID_UTILITY);

                return bid;
        }

        /**
         * This function determines the accept probability for an offer. At t=0 it
         * will prefer high-utility offers. As t gets closer to 1, it will accept
         * lower utility offers with increasing probability. it will never accept
         * offers with utility 0.
         * 
         * @param u
         *            is the utility
         * @param t
         *            is the time as fraction of the total available time (t=0 at
         *            start, and t=1 at end time)
         * @return the probability of an accept at time t
         * @throws Exception
         *             if you use wrong values for u or t.
         * 
         */
        double Paccept(double u, double t1) throws Exception {
                double t = t1 * t1 * t1; // steeper increase when deadline approaches.
                if (u < 0 || u > 1.05)
                        throw new Exception("utility " + u + " outside [0,1]");
                // normalization may be slightly off, therefore we have a broad boundary
                // up to 1.05
                if (t < 0 || t > 1)
                        throw new Exception("time " + t + " outside [0,1]");
                if (u > 1.)
                        u = 1;
                if (t == 0.5)
                        return u;
                return (u - 2. * u * t
                                + 2. * (-1. + t + Math.sqrt(sq(-1. + t) + u * (-1. + 2 * t))))
                                / (-1. + 2 * t);
        }

        double sq(double x) {
                return x * x;
        }

        @Override
        public SupportedNegotiationSetting getSupportedNegotiationSetting() {
                return SupportedNegotiationSetting.getLinearUtilitySpaceInstance();
        }

        @Override
        public String getDescription() {
                return "Random bids until good offer is received";
        }

}