source: src/main/java/agents/DecUtilAgent.java@ 209

package agents;

import java.util.ArrayList;
import java.util.Collections;

import genius.core.Agent;
import genius.core.Bid;
import genius.core.BidIterator;
import genius.core.actions.Accept;
import genius.core.actions.Action;
import genius.core.actions.ActionWithBid;
import genius.core.actions.Offer;

/**
 * This agent just offers all bids in decreasing utility order to opponent. The
 * acceptance criterion is the same as with the SimpleAgent.
 * 
 * @author W.Pasman
 * 
 */
public class DecUtilAgent extends Agent {
        private Action actionOfPartner = null;
        ArrayList<Bid> bids = new ArrayList<Bid>();
        int nextBidIndex = 0; // what's the next bid from bids to be done.

        @Override
        public void init() {

                BidIterator biter = new BidIterator(utilitySpace.getDomain());
                while (biter.hasNext())
                        bids.add(biter.next());
                Collections.sort(bids, new BidComparator(utilitySpace));
        }

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

        public Action chooseAction() {
                Action action = null;
                try {
                        if (actionOfPartner == null)
                                action = new Offer(getAgentID(), bids.get(nextBidIndex++));
                        if (actionOfPartner instanceof Offer) {
                                action = new Offer(getAgentID(), bids.get(nextBidIndex++));
                        }
                        // Thread.sleep(300); // 3 bids per second is good enough.
                } catch (Exception e) {
                        System.out.println("Exception in ChooseAction:" + e.getMessage());
                        // best guess if things go wrong.
                        action = new Accept(getAgentID(),
                                        ((ActionWithBid) actionOfPartner).getBid());
                }
                return action;
        }

        /**
         * 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;
        }
}