Ejemplo n.º 1
0
  public static FibonacciHeap<NodeInfoHelper> initialStartSet(
      long startNode,
      long endNode,
      HashMap<Long, FibonacciHeapNode<NodeInfoHelper>> nodeHelperCache) {
    FibonacciHeap<NodeInfoHelper> openSet = new FibonacciHeap<NodeInfoHelper>();

    NodeInfo start = OSMData.nodeHashMap.get(startNode);
    NodeInfoHelper initial;
    FibonacciHeapNode<NodeInfoHelper> fInitial;
    // initial start end set
    if (start.isIntersect()) {
      // initial
      initial = new NodeInfoHelper(startNode);
      initial.setCost(0);
      initial.setHeuristic(estimateHeuristic(startNode, endNode));
      fInitial = new FibonacciHeapNode<NodeInfoHelper>(initial);
      openSet.insert(fInitial, initial.getTotalCost()); // push the start node
      nodeHelperCache.put(initial.getNodeId(), fInitial); // add cache
    } else {
      EdgeInfo edge = start.getOnEdgeList().getFirst();
      double speed = edge.getTravelSpeed();
      int travelTime = 1; // second
      int distance;
      if (!edge.isOneway()) {
        // distance from start to middle
        distance = edge.getStartDistance(startNode);
        travelTime = (int) Math.round(distance / speed * OSMParam.MILLI_PER_SECOND);
        initial = new NodeInfoHelper(edge.getStartNode());
        initial.setCost(travelTime);
        initial.setHeuristic(estimateHeuristic(edge.getStartNode(), endNode));
        fInitial = new FibonacciHeapNode<NodeInfoHelper>(initial);
        openSet.insert(fInitial, initial.getTotalCost()); // push the start node
        nodeHelperCache.put(initial.getNodeId(), fInitial); // add cache
      }
      distance = edge.getEndDistance(startNode);
      travelTime = (int) Math.round(distance / speed * OSMParam.MILLI_PER_SECOND);
      initial = new NodeInfoHelper(edge.getEndNode());
      initial.setCost(travelTime);
      initial.setHeuristic(estimateHeuristic(edge.getEndNode(), endNode));
      fInitial = new FibonacciHeapNode<NodeInfoHelper>(initial);
      openSet.insert(fInitial, initial.getTotalCost()); // push the start node
      nodeHelperCache.put(initial.getNodeId(), fInitial); // add cache
    }
    return openSet;
  }
Ejemplo n.º 2
0
  /**
   * routing using A* algorithm with fibonacci heap basically same as routingAStar function
   *
   * @param startNode
   * @param endNode
   * @param startTime
   * @param pathNodeList return path
   * @return
   */
  public static double routingAStarFibonacci(
      long startNode, long endNode, int startTime, int dayIndex, ArrayList<Long> pathNodeList) {
    System.out.println("start finding the path...");
    int debug = 0;
    double totalCost = -1;
    try {
      // test store transversal nodes
      // HashSet<Long> transversalSet = new HashSet<Long>();

      if (!OSMData.nodeHashMap.containsKey(startNode)
          || !OSMData.nodeHashMap.containsKey(endNode)) {
        System.err.println("cannot find start or end node!");
        return -1;
      }

      if (startNode == endNode) {
        System.out.println("start node is the same as end node.");
        return 0;
      }

      HashSet<Long> closedSet = new HashSet<Long>();
      HashMap<Long, FibonacciHeapNode<NodeInfoHelper>> nodeHelperCache =
          new HashMap<Long, FibonacciHeapNode<NodeInfoHelper>>();

      FibonacciHeap<NodeInfoHelper> openSet = initialStartSet(startNode, endNode, nodeHelperCache);
      HashSet<Long> endSet = initialEndSet(endNode);
      NodeInfoHelper current = null;
      FibonacciHeapNode<NodeInfoHelper> fCurrent = null;

      while (!openSet.isEmpty()) {
        // remove current from openset
        fCurrent = openSet.min();
        openSet.removeMin();
        current = fCurrent.getData();

        // if(!transversalSet.contains(current.getNodeId()))
        //	transversalSet.add(current.getNodeId());

        long nodeId = current.getNodeId();
        // add current to closedset
        closedSet.add(nodeId);
        if (endSet.contains(nodeId)) { // find the destination
          current = current.getEndNodeHelper(endNode);
          totalCost = current.getCost();
          break;
        }
        // for time dependent routing
        int timeIndex =
            startTime
                + (int)
                    (current.getCost() / OSMParam.SECOND_PER_MINUTE / OSMRouteParam.TIME_INTERVAL);
        if (timeIndex
            > OSMRouteParam.TIME_RANGE
                - 1) // time [6am - 9 pm], we regard times after 9pm as constant edge weights
        timeIndex = OSMRouteParam.TIME_RANGE - 1;
        LinkedList<ToNodeInfo> adjNodeList = OSMData.adjListHashMap.get(nodeId);
        if (adjNodeList == null) continue; // this node cannot go anywhere
        double arriveTime = current.getCost();
        // for each neighbor in neighbor_nodes(current)
        for (ToNodeInfo toNode : adjNodeList) {
          debug++;
          long toNodeId = toNode.getNodeId();
          int travelTime;
          if (toNode.isFix()) // fix time
          travelTime = toNode.getTravelTime();
          else // fetch from time array
          travelTime = toNode.getSpecificTravelTime(dayIndex, timeIndex);
          // tentative_g_score := g_score[current] + dist_between(current,neighbor)
          double costTime = arriveTime + (double) travelTime / OSMParam.MILLI_PER_SECOND;
          // tentative_f_score := tentative_g_score + heuristic_cost_estimate(neighbor, goal)
          double heuristicTime = estimateHeuristic(toNodeId, endNode);
          double totalCostTime = costTime + heuristicTime;
          // if neighbor in closedset and tentative_f_score >= f_score[neighbor]
          if (closedSet.contains(toNodeId)
              && nodeHelperCache.get(toNodeId).getData().getTotalCost() <= totalCostTime) {
            continue;
          }
          NodeInfoHelper node = null;
          FibonacciHeapNode<NodeInfoHelper> fNode = null;
          // if neighbor not in openset or tentative_f_score < f_score[neighbor]
          if (!nodeHelperCache.containsKey(toNodeId)) { // neighbor not in openset
            // create new one
            node = new NodeInfoHelper(toNodeId);
            node.setCost(costTime);
            node.setHeuristic(heuristicTime);
            node.setParentId(nodeId);
            fNode = new FibonacciHeapNode<NodeInfoHelper>(node);
            openSet.insert(fNode, node.getTotalCost());
            nodeHelperCache.put(node.getNodeId(), fNode);
          } else if (nodeHelperCache.get(toNodeId).getData().getTotalCost()
              > totalCostTime) { // neighbor in openset
            fNode = nodeHelperCache.get(toNodeId);
            node = fNode.getData();
            // update information
            node.setCost(costTime);
            node.setHeuristic(heuristicTime);
            node.setParentId(nodeId);
            if (closedSet.contains(toNodeId)) { // neighbor in closeset
              closedSet.remove(toNodeId); // remove neighbor form colseset
              openSet.insert(fNode, node.getTotalCost());
            } else { // neighbor in openset, decreaseKey
              openSet.decreaseKey(fNode, node.getTotalCost());
            }
          }
        }
      }
      if (totalCost != -1) {
        long traceNodeId = current.getNodeId();
        pathNodeList.add(traceNodeId); // add end node
        traceNodeId = current.getParentId();
        while (traceNodeId != 0) {
          pathNodeList.add(traceNodeId); // add node
          fCurrent = nodeHelperCache.get(traceNodeId);
          current = fCurrent.getData();
          traceNodeId = current.getParentId();
        }
        Collections.reverse(pathNodeList); // reverse the path list
        System.out.println("find the path successful!");
      } else {
        System.out.println("can not find the path!");
      }
      // OSMOutput.generateTransversalNodeKML(transversalSet, nodeHashMap);
    } catch (Exception e) {
      e.printStackTrace();
      System.err.println(
          "tdsp: debug code " + debug + ", start node " + startNode + ", end node " + endNode);
    }
    return totalCost;
  }