source: src/main/java/negotiator/boaframework/offeringstrategy/other/TimeDependent_Offering.java

package negotiator.boaframework.offeringstrategy.other;

import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import genius.core.bidding.BidDetails;
import genius.core.boaframework.BOAparameter;
import genius.core.boaframework.NegotiationSession;
import genius.core.boaframework.NoModel;
import genius.core.boaframework.OMStrategy;
import genius.core.boaframework.OfferingStrategy;
import genius.core.boaframework.OpponentModel;
import genius.core.boaframework.SortedOutcomeSpace;

/**
 * This is an abstract class used to implement a TimeDependentAgent Strategy
 * adapted from [1] [1] S. Shaheen Fatima Michael Wooldridge Nicholas R.
 * Jennings Optimal Negotiation Strategies for Agents with Incomplete
 * Information http://eprints.ecs.soton.ac.uk/6151/1/atal01.pdf
 * 
 * The default strategy was extended to enable the usage of opponent models.
 * 
 * Note that this agent is not fully equivalent to the theoretical model,
 * loading the domain may take some time, which may lead to the agent skipping
 * the first bid. A better implementation is GeniusTimeDependent_Offering.
 * 
 * @author Alex Dirkzwager, Mark Hendrikx
 */
public class TimeDependent_Offering extends OfferingStrategy {

        /**
         * k \in [0, 1]. For k = 0 the agent starts with a bid of maximum utility
         */
        private double k;
        /** Maximum target utility */
        private double Pmax;
        /** Minimum target utility */
        private double Pmin;
        /** Concession factor */
        private double e;
        /** Outcome space */
        SortedOutcomeSpace outcomespace;

        /**
         * Empty constructor used for reflection. Note this constructor assumes that
         * init is called next.
         */
        public TimeDependent_Offering() {
        }

        public TimeDependent_Offering(NegotiationSession negoSession, OpponentModel model, OMStrategy oms, double e,
                        double k, double max, double min) {
                this.e = e;
                this.k = k;
                this.Pmax = max;
                this.Pmin = min;
                this.negotiationSession = negoSession;
                outcomespace = new SortedOutcomeSpace(negotiationSession.getUtilitySpace());
                negotiationSession.setOutcomeSpace(outcomespace);
                this.opponentModel = model;
                this.omStrategy = oms;
        }

        /**
         * Method which initializes the agent by setting all parameters. The
         * parameter "e" is the only parameter which is required.
         */
        @Override
        public void init(NegotiationSession negoSession, OpponentModel model, OMStrategy oms,
                        Map<String, Double> parameters) throws Exception {
                if (parameters.get("e") != null) {
                        this.negotiationSession = negoSession;

                        outcomespace = new SortedOutcomeSpace(negotiationSession.getUtilitySpace());
                        negotiationSession.setOutcomeSpace(outcomespace);

                        this.e = parameters.get("e");

                        if (parameters.get("k") != null)
                                this.k = parameters.get("k");
                        else
                                this.k = 0;

                        if (parameters.get("min") != null)
                                this.Pmin = parameters.get("min");
                        else
                                this.Pmin = negoSession.getMinBidinDomain().getMyUndiscountedUtil();

                        if (parameters.get("max") != null) {
                                Pmax = parameters.get("max");
                        } else {
                                BidDetails maxBid = negoSession.getMaxBidinDomain();
                                Pmax = maxBid.getMyUndiscountedUtil();
                        }

                        this.opponentModel = model;
                        this.omStrategy = oms;
                } else {
                        throw new Exception("Constant \"e\" for the concession speed was not set.");
                }
        }

        @Override
        public BidDetails determineOpeningBid() {
                return determineNextBid();
        }

        /**
         * Simple offering strategy which retrieves the target utility and looks for
         * the nearest bid if no opponent model is specified. If an opponent model
         * is specified, then the agent return a bid according to the opponent model
         * strategy.
         */
        @Override
        public BidDetails determineNextBid() {
                double time = negotiationSession.getTime();
                double utilityGoal;
                utilityGoal = p(time);

                // System.out.println("[e=" + e + ", Pmin = " +
                // BilateralAgent.round2(Pmin) + "] t = " + BilateralAgent.round2(time)
                // + ". Aiming for " + utilityGoal);

                // if there is no opponent model available
                if (opponentModel instanceof NoModel) {
                        nextBid = negotiationSession.getOutcomeSpace().getBidNearUtility(utilityGoal);
                } else {
                        nextBid = omStrategy.getBid(outcomespace, utilityGoal);
                }
                return nextBid;
        }

        /**
         * From [1]:
         * 
         * A wide range of time dependent functions can be defined by varying the
         * way in which f(t) is computed. However, functions must ensure that 0 <=
         * f(t) <= 1, f(0) = k, and f(1) = 1.
         * 
         * That is, the offer will always be between the value range, at the
         * beginning it will give the initial constant and when the deadline is
         * reached, it will offer the reservation value.
         * 
         * For e = 0 (special case), it will behave as a Hardliner.
         */
        public double f(double t) {
                if (e == 0)
                        return k;
                double ft = k + (1 - k) * Math.pow(t, 1.0 / e);
                return ft;
        }

        /**
         * Makes sure the target utility with in the acceptable range according to
         * the domain Goes from Pmax to Pmin!
         * 
         * @param t
         * @return double
         */
        public double p(double t) {
                return Pmin + (Pmax - Pmin) * (1 - f(t));
        }

        public NegotiationSession getNegotiationSession() {
                return negotiationSession;
        }

        @Override
        public Set<BOAparameter> getParameterSpec() {
                Set<BOAparameter> set = new HashSet<BOAparameter>();
                set.add(new BOAparameter("e", 1.0, "Concession rate"));
                set.add(new BOAparameter("k", 0.0, "Offset"));
                set.add(new BOAparameter("min", 0.0, "Minimum utility"));
                set.add(new BOAparameter("max", 0.99, "Maximum utility"));

                return set;
        }

        @Override
        public String getName() {
                return "Other - TimeDependent Offering";
        }
}