public static actionsFromNodes ( List |
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nodeList | List |
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return | List |
/** * * @param problem * @param frontier * @return if goal found, the list of actions to the Goal. If already at the * goal you will receive a List with a single NoOp Action in it. If * fail to find the Goal, an empty list will be returned to indicate * that the search failed. */ public virtual List <Action> search(Problem problem, Queue <Node> frontier) { this.frontier = frontier; clearInstrumentation(); // initialize the frontier using the initial state of the problem Node root = new Node(problem.getInitialState()); if (isCheckGoalBeforeAddingToFrontier()) { if (SearchUtils.isGoalState(problem, root)) { return(SearchUtils.actionsFromNodes(root.getPathFromRoot())); } } frontier.Enqueue(root); setQueueSize(frontier.Count); while (!(frontier.Count == 0)) { // choose a leaf node and remove it from the frontier Node nodeToExpand = popNodeFromFrontier(); setQueueSize(frontier.Count); // Only need to check the nodeToExpand if have not already // checked before adding to the frontier if (!isCheckGoalBeforeAddingToFrontier()) { // if the node contains a goal state then return the // corresponding solution if (SearchUtils.isGoalState(problem, nodeToExpand)) { setPathCost(nodeToExpand.getPathCost()); return(SearchUtils.actionsFromNodes(nodeToExpand .getPathFromRoot())); } } // expand the chosen node, adding the resulting nodes to the // frontier foreach (Node fn in getResultingNodesToAddToFrontier(nodeToExpand, problem)) { if (isCheckGoalBeforeAddingToFrontier()) { if (SearchUtils.isGoalState(problem, fn)) { setPathCost(fn.getPathCost()); return(SearchUtils.actionsFromNodes(fn .getPathFromRoot())); } } frontier.Enqueue(fn); } setQueueSize(frontier.Count); } // if the frontier is empty then return failure return(failure()); }
public static bool isGoalState(Problem p, Node n) { bool isGoal = false; GoalTest gt = p.getGoalTest(); if (gt.isGoalState(n.getState())) { if (gt is SolutionChecker) { isGoal = ((SolutionChecker)gt).isAcceptableSolution( SearchUtils.actionsFromNodes(n.getPathFromRoot()), n .getState()); } else { isGoal = true; } } return(isGoal); }