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descTime User Activity Comment
16:19, 7 December 2013Rednaxela (Talk | contribs)Comment text edited 
16:05, 7 December 2013Rednaxela (Talk | contribs)New reply created (Reply to Running Error - Robot is not stopping, forcing a stop)
15:43, 7 December 2013Rednaxela (Talk | contribs)Comment text edited (fix syntax highlighting so I can read it)
07:13, 7 December 2013Lavenderwong (Talk | contribs)Comment text edited 
07:03, 7 December 2013Lavenderwong (Talk | contribs)New thread created 
Edited by 2 users.
Last edit: 15:43, 7 December 2013

When I start the battlefield,my robot and other enemy are frozen. The println messages are not displayed in the robot console. But the command prompt shows the following error. I check that the cause of error is the addition of node in my queue (queue.add(n)). However, this line of code shall be fine i guess. So I would like to ask how to solve this error message? (this part of my program is for path finding using bfs)

Thank you.


          • BATTLE 1, ROUND 1 *****

TURN 1: StudentRobot* (1) hard deadline exceeded - 532809us

Err> Robot StudentRobot* (1) is not stopping. Forcing a stop.

Err> Robot StudentRobot* (2) is not stopping. Forcing a stop.

Average computation time per turn: 511706

Max turn computation time: 532809

	private boolean pathFinding_BFS(Node start, Node end){
		LinkedList<Node> queue = new LinkedList<Node>();
		queue.add(start);
		start.setMarked();
		while (!queue.isEmpty()){
			Node temp = (Node)queue.poll();
			System.out.println("first node:" + temp.getPointInPath().getX() + " y " + temp.getPointInPath().getY());
			if (temp.equals(end)){
				temp.setPrevNodeInPath(temp.getPrevNodeInPath());
				return true;
			}else{
				for (Node n : temp.getAdjacentNode()){	
					System.out.println("in node:" + n.getPointInPath().getX() + " y " + 
n.getPointInPath().getY());
					if (!n.isMarked()){
						n.setMarked();
						n.setPrevNodeInPath(temp);
						System.out.println("test n");
						queue.add(n);  //problem here
					}
				}
			}
		}
		return false;
	}
 
 
	public  List<Point> getShortestPath(Point start){
		Node src = new Node(start);
		List<Point> path = new ArrayList<Point>();
		for (int i=0;i<endup.size();i++){
			Node destination = new Node(endup.get(i));
			if (pathFinding_BFS(src, destination)){
				while (destination.getPrevNodeInPath() != null){
					destination = destination.getPrevNodeInPath();
					path.add(destination.getPointInPath());
				}
				Collections.reverse(path);
				return path;
			}
		}
		return path;
	}
Lavenderwong (talk)07:03, 7 December 2013

I don't see any clear problems with that code there. The only way I could see it looping forever is if either setMarked and isMarked are not working correctly, or some other code being called is unsetting the marks in the middle of that loop.

It is possible that this search is just plain taking far too long (>533ms on your computer) because of there being too many nodes to search before it finds the desired end point. How many nodes are you running this code with? If this is indeed the case, you should do one or both of the following: 1) Reduce the number of nodes, and/or 2) Switch from a full breadth first search to a more efficient algorithm such as A*

To figure out what the problem is, I would tend to suggest running this under a debugger, and step through what is happening.

EDIT: Oh, and another possible thing that comes to mind, is perhaps your problem has nothing to do with your node search code. Maybe your robot is just never calling any of the methods that signal to Robocode that has finished it's turn.

Rednaxela (talk)16:05, 7 December 2013
 
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