Example usage for java.util PriorityQueue peek

Introduction

In this page you can find the example usage for java.util PriorityQueue peek.

Prototype

public E peek()

Source Link

Usage

From source file:exploration.rendezvous.MultiPointRendezvousStrategy.java

private void calculateRendezvousRandomSampling(int timeElapsed) {
    RendezvousAgentData rvd = agent.getRendezvousAgentData();
    // Only calculate rv every several time steps at most
    if (rvd.getTimeSinceLastRVCalc() < SimConstants.RV_REPLAN_INTERVAL) {
        return;/* ww  w . j a  va2 s . c  o  m*/
    } else {
        rvd.setTimeSinceLastRVCalc(0);
    }

    TeammateAgent relay = agent.getParentTeammate();
    generatedPoints = SampleEnvironmentPoints(agent, settings.SamplePointDensity);
    connectionsToBase = FindCommLinks(generatedPoints, agent);
    PriorityQueue<NearRVPoint> pointsNearFrontier = GetPointsWithinDistOfFrontier(generatedPoints, 100);

    int pathsCalculated = 0;

    //Now for top K points, let's calculate p' distances to base, and find the nearest point connected to base
    PriorityQueue<NearRVPoint> pointsNearFrontierReal = new PriorityQueue<NearRVPoint>();
    for (int k = 0; (k < 50) && !pointsNearFrontier.isEmpty(); k++) {
        NearRVPoint p = pointsNearFrontier.poll();
        double minDistToBase = Double.MAX_VALUE;

        for (CommLink link : p.commLinks) {
            NearRVPoint connectedPoint = link.getRemotePoint();

            pathsCalculated = findNearestPointInBaseCommRange(connectedPoint, connectionsToBase, agent);

            if (connectedPoint.distanceToParent < minDistToBase) {
                minDistToBase = connectedPoint.distanceToParent;
                p.commLinkClosestToBase = link;
            }
        }
        //At this point, for p, we know:
        //  1. Connected point p' that is nearest to comm range of Base
        //  2. Distance from p' to comm range of Base
        //  3. Nearest point from p' that is within comm range of Base
        //So we know how long each point p will have to wait for relay, and so can estimate
        //where explorer will be at the time, to calculate regret accurately.

        //For now, just calculate accurate distance to next frontier:
        Path pathToFrontier = agent.calculatePath(p, getExplorerFrontier(), false, false);
        double distToFrontier = Double.MAX_VALUE;
        if (pathToFrontier.found) {
            distToFrontier = pathToFrontier.getLength();
        }
        pathsCalculated++;
        p.setDistanceToFrontier(distToFrontier);

        if (p.commLinkClosestToBase == null || p.commLinkClosestToBase.getRemotePoint() == null) {
            //something went wrong, set RV to our current location and return
            Rendezvous meetingLocation = new Rendezvous(agent.getLocation());
            Point baseLocation = agent.getTeammate(agent.getParentTeammate().getParent()).getLocation();
            meetingLocation.parentsRVLocation = new Rendezvous(baseLocation);
            rvd.setParentRendezvous(meetingLocation);
            calculateRVTimings(timeElapsed);
            return;
        }

        p.utility = NearRVPoint.getFullRVUtility(p.distanceToFrontier,
                p.commLinkClosestToBase.getRemotePoint().distanceToParent,
                p.commLinkClosestToBase.numObstacles);

        pointsNearFrontierReal.add(p);
    }

    //Now just need to retrieve the best point
    NearRVPoint childPoint = pointsNearFrontierReal.peek();
    NearRVPoint parentPoint = childPoint.commLinkClosestToBase.getRemotePoint();

    Rendezvous meetingLocation = new Rendezvous(childPoint);
    meetingLocation.setParentLocation(parentPoint);

    Rendezvous parentsMeetingLocation = new Rendezvous(parentPoint.parentPoint);
    Point baseLocation = agent.getTeammate(agent.getParentTeammate().getParent()).getLocation();
    parentsMeetingLocation
            .setParentLocation(agent.getTeammate(agent.getParentTeammate().getParent()).getLocation());

    meetingLocation.parentsRVLocation = parentsMeetingLocation;
    rvd.setParentRendezvous(meetingLocation);

    Rendezvous backupRV = new Rendezvous(childPoint);
    rvd.setParentBackupRendezvous(backupRV);

    calculateRVTimings(timeElapsed);

    displayData.setGeneratedPoints(generatedPoints);
    displayData.setPointsNearFrontier(pointsNearFrontier);
}