source: src/main/java/agents/ai2014/group8/OpponentModel.java@ 127

package agents.ai2014.group8;

import java.util.ArrayList;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;

import genius.core.AgentID;
import genius.core.Bid;
import genius.core.issue.Issue;
import genius.core.issue.Value;

/**
 * Class that models opponent preference profile
 *
 */
public class OpponentModel {

        // agent being modeled
        public AgentID agent;

        // list of bids made by agent
        private List<Bid> bidsMadeByAgent;

        // list of issues and their associated weights
        private Map<Issue, Double> issueWeights;

        // mapping of Issues to their values and number of bids made for each value
        private Map<Issue, Map<Value, Integer>> issueValueFrequencies;

        // mapping of Issues to their values and number of bids made for each value
        private Map<Issue, Map<Value, Integer>> sortedIssueValueFrequencies;

        // mapping of Issues to their values and number of bids made for each value
        private Map<Issue, Map<Value, Double>> issueEvaluationValues;

        /**
         * class constructor
         * 
         * @param opponentAgent
         *            agent whose preference is being modeled
         */
        public OpponentModel(AgentID opponentAgent, List<Issue> issues) {

                this.agent = opponentAgent;

                this.bidsMadeByAgent = new ArrayList<Bid>();

                // get the issues that are in the domain
                List<Issue> issuesInDomain = issues;

                this.issueWeights = new HashMap<Issue, Double>();
                this.issueValueFrequencies = new HashMap<Issue, Map<Value, Integer>>();
                this.issueEvaluationValues = new HashMap<Issue, Map<Value, Double>>();

                // for each issue in domain, add an entry in list of preferences
                // initialize each issue with the initial weights
                for (Issue issue : issuesInDomain) {
                        this.issueWeights.put(issue, 0.0);

                        this.issueValueFrequencies
                                        .put(issue, new HashMap<Value, Integer>());

                        this.issueEvaluationValues.put(issue, new HashMap<Value, Double>());
                }
        }

        /**
         * store bids made by this opponent for preference analysis
         * 
         * @param bid
         */
        public void AddBid(Bid bid) {
                if (bid != null) {
                        this.bidsMadeByAgent.add(bid);

                        this.UpdateIssueValueFrequencies(bid);
                }

                this.AnalyzeIssueValuePreferences();
        }

        /**
         * update the count of bids made for every issue value
         * 
         * @param newBid
         *            the bid based on which to update frequencies
         */
        public void UpdateIssueValueFrequencies(Bid newBid) {
                for (int i = 0; i < newBid.getIssues().size(); i++) {
                        Issue issue = newBid.getIssues().get(i);
                        Value issueValue = null;

                        try {
                                issueValue = newBid.getValue(i + 1);
                        } catch (Exception e) {
                                e.printStackTrace();
                                return;
                        }

                        Map<Value, Integer> valueMapping = issueValueFrequencies.get(issue);

                        int currentFrequency = 0;
                        if (valueMapping.containsKey(issueValue)) {
                                currentFrequency = valueMapping.get(issueValue);
                                currentFrequency++;

                                valueMapping.put(issueValue, currentFrequency);
                        } else {
                                currentFrequency++;
                                valueMapping.put(issueValue, currentFrequency);
                        }
                }
        }

        /**
         * method to analyze agent issue value preferences by bid frequency analysis
         */
        public void AnalyzeIssueValuePreferences() {
                Iterator it = this.issueValueFrequencies.entrySet().iterator();

                sortedIssueValueFrequencies = new HashMap<Issue, Map<Value, Integer>>();

                while (it.hasNext()) {
                        Map.Entry<Issue, Map<Value, Integer>> pair = (Map.Entry<Issue, Map<Value, Integer>>) it
                                        .next();
                        Issue issue = pair.getKey();
                        Map<Value, Integer> valueFrequencies = pair.getValue();

                        // assign issue weights as inverse of number of different choices
                        // made for the issue
                        double issueWeight = 1 / (double) valueFrequencies.size();
                        this.issueWeights.put(issue, issueWeight);

                        // sort the issue values by frequency of bids that target the
                        // particular value
                        ValueComparator bvc = new ValueComparator(valueFrequencies);
                        TreeMap<Value, Integer> sorted_map = new TreeMap<Value, Integer>(
                                        bvc);
                        sorted_map.putAll(valueFrequencies);

                        int highestFrequency = sorted_map.firstEntry().getValue();
                        Iterator valueIterator = sorted_map.entrySet().iterator();
                        Map<Value, Double> evals = new HashMap<Value, Double>();

                        // evaluation value of an issue value is the number of times the
                        // value was bid for
                        // divided by the number of times the highest bid value was bid for
                        while (valueIterator.hasNext()) {
                                Map.Entry<Value, Integer> valuePair = (Map.Entry<Value, Integer>) valueIterator
                                                .next();

                                int valueFrequency = valuePair.getValue();

                                double evaluationValue = valueFrequency
                                                / (double) highestFrequency;

                                evals.put(valuePair.getKey(), evaluationValue);
                        }

                        this.issueEvaluationValues.put(issue, evals);
                        this.sortedIssueValueFrequencies.put(issue, sorted_map);
                }

                this.UpdateIssueWeights();
        }

        /**
         * method to estimate issue weights
         */
        public void UpdateIssueWeights() {
                Iterator it = this.issueWeights.entrySet().iterator();
                double weightSum = 0.0;

                while (it.hasNext()) {
                        Map.Entry<Value, Double> weightPair = (Map.Entry<Value, Double>) it
                                        .next();

                        weightSum += weightPair.getValue();
                }

                it = this.issueWeights.entrySet().iterator();

                while (it.hasNext()) {
                        Map.Entry<Value, Double> weightPair = (Map.Entry<Value, Double>) it
                                        .next();

                        weightPair.setValue(weightPair.getValue() / weightSum);
                }
        }

        /**
         * method to evaluate the utility of a bid for this agent
         * 
         * @param bidToEvaluate
         *            bid whose utility to evaluate
         * @return utility of bid for this agent
         */
        public double EvaluateBidUtility(Bid bidToEvaluate) {
                double utilityValue = 0.0;

                // utility value = u1 * w1 + u2 * w2 + ...
                for (int i = 0; i < bidToEvaluate.getIssues().size(); i++) {
                        Issue issue = bidToEvaluate.getIssues().get(i);
                        Value issueValue = null;

                        try {
                                issueValue = bidToEvaluate.getValue(i + 1);
                        } catch (Exception e) {
                                e.printStackTrace();
                        }

                        if (issueValue != null) {
                                double issueWeight = this.issueWeights.get(issue);

                                Map<Value, Double> evaluationValues = this.issueEvaluationValues
                                                .get(issue);
                                double evaluationValue = 0.0;

                                if (evaluationValues.isEmpty() == false
                                                && evaluationValues.containsKey(issueValue)) {
                                        evaluationValue = evaluationValues.get(issueValue);
                                }

                                utilityValue += issueWeight * evaluationValue;
                        }
                }

                return utilityValue;
        }

        /**
         * overridden equals method to compare two OpponentModel objects they are
         * equal if they model the same agent, determined by agentID
         * 
         * @param object
         *            object being compared
         */
        @Override
        public boolean equals(Object object) {
                boolean result = false;

                if (object instanceof OpponentModel) {
                        OpponentModel toCompare = (OpponentModel) object;

                        if (this.agent.equals(toCompare.agent)) {
                                result = true;
                        }
                }

                return result;
        }

        /**
         * Class that is used to compare issue values
         *
         */
        class ValueComparator implements Comparator<Value> {
                Map<Value, Integer> base;

                public ValueComparator(Map<Value, Integer> base) {
                        this.base = base;
                }

                // Note: this comparator imposes orderings that are inconsistent with
                // equals.
                public int compare(Value a, Value b) {
                        if (base.get(a) >= base.get(b)) {
                                return -1;
                        } else {
                                return 1;
                        }
                }
        }
}