source: src/main/java/agents/anac/y2010/AgentSmith/BidComparator.java

package agents.anac.y2010.AgentSmith;
import java.util.Comparator;

import genius.core.Bid;

/*
 * The BidComparator compares two given bids. This class is used to slowly descent to the opponent while
 * staying above the given threshold (OWN_UTILITY_WEIGHT), which determines how much he values his
 * own interest or wants to give in a lot to the opponent to make him 'happy'.
 */
public class BidComparator implements Comparator<Bid> {
        private PreferenceProfileManager fPreferenceProfile;
        
        
        
        public BidComparator(PreferenceProfileManager pProfile) {
                this.fPreferenceProfile = pProfile;
        }
        
        /*
         * returns 1 if his own bid is better than the opponents, -1 otherwise
         */
        public int compare(Bid b1, Bid b2) {
                return getMeasure(b2) > getMeasure(b1) ? -1 : 1;
        }
        
        /*
         * returns a double that represents the value of a value of a bid, taking into account both the agents 
         * own and opponents' utility. 
         */
        public double getMeasure(Bid b1) {
                double a = (1 - this.fPreferenceProfile.getMyUtility(b1)); 
                double b = (1 - this.fPreferenceProfile.getOpponentUtility(b1));
                
                double alpha = Math.atan(b/a);
                
                return a + b + (0.5*Math.PI / alpha) * 0.5*Math.PI;
        }
        
}