Python PriorityQueue.PriorityQueue類代碼示例

    def test_uselist(self):
        '''Push a list onto queue and them remove it'''
        pq = PriorityQueue()
        l = []

        pq.push(0,range(0, 10))
        self.assertEqual(pq.pop()[1], range(0, 10))

 def test_dict(self):
     '''Push a dictionary'''
     pq = PriorityQueue()
     d = {'a':10, 'b':4}
     
     pq.push(0, d)
     self.assertEqual(pq.pop()[1], d)

 def test_pushpop(self):
     '''Push items onto queue and then remove them'''
     pq = PriorityQueue()
     for i in range(0, 10):
         pq.push(0,i)
         
     for i in range(0, 10):
         self.assertEqual(pq.pop()[1], i)

class PriorityEdgeList:
    def __init__(self):
        self.edges = []
        self.priorityEdges = PriorityQueue()
        self.empty = True

    def InsertEdge(self, y, w):
        self.priorityEdges.add_task(y, w)
        self.edges.append( Graphs.Edge(y,w))
        self.empty = False

def primsAlgorithm(graph, start, surface):
    
    for v in graph:
        v.setStatus(0)
        v.setParent(None)
        
    pq = PriorityQueue()
    #heapq.heappush(pq, (0, start))
    pq.enQueue((0, start))
    while (not pq.isEmpty()):
        current = pq.deQueue()[1]
        current.setStatus(2)
        if(current.getParent() != None):
            graph.drawEdge(current.getParent(), current, surface, "yellow")
            time.sleep(0.5)
            #print(str(current.getParent().getId()) + "->" + str(current.getId()))
        for neighbour in current.getNeighbours():
                    if (neighbour.getStatus() == 0):        
                        neighbour.setStatus(1)
                        neighbour.setParent(current)
                        neighbour.setpqWeight(current.neighbours[neighbour])
                        #print(str(neighbour.getpqWeight()))
                        pq.enQueue((neighbour.getpqWeight(), neighbour))
                    elif (neighbour.getStatus() == 1):
                        if (neighbour.getpqWeight() > current.neighbours[neighbour]):
                            old = (neighbour.getpqWeight(), neighbour)
                            neighbour.setpqWeight(current.neighbours[neighbour])
                            pq.updatePriority(old, (neighbour.getpqWeight(), neighbour))
                            neighbour.setParent(current)    
    """

 def prims(self, graph, start, canvas):
     for v in graph:
         v.setStatus(0)
         v.setParent(None)
             
     pq = PriorityQueue()
     pq.enQueue((0, start))
     while (not pq.isEmpty()):
         current = pq.deQueue()[1]
         current.setStatus(2)
         if(current.getParent() != None):
             graph.drawEdge(current.getParent(), current, canvas, "yellow")
             canvas.update()
             time.sleep(0.5)
         for neighbour in current.getNeighbours():
             if (neighbour.getStatus() == 0):  
                 # Encountered a new vertex
                 neighbour.setStatus(1)
                 neighbour.setParent(current)
                 neighbour.setpqWeight(current.neighbours[neighbour])
                 pq.enQueue((neighbour.getpqWeight(), neighbour))
             elif (neighbour.getStatus() == 1):
                 if (neighbour.getpqWeight() > current.neighbours[neighbour]):
                     # Found smaller weight, update accordingly
                     old = (neighbour.getpqWeight(), neighbour)
                     neighbour.setpqWeight(current.neighbours[neighbour])
                     pq.updatePriority(old, (neighbour.getpqWeight(), neighbour))
                     neighbour.setParent(current)

 def test_priority(self):
     '''Test the priority portion of the priority queue'''
     pq = PriorityQueue()
     for i in range(0, 10):
         pq.push(i,i)
         
     for i in range(0, 10):
         pri, item = pq.pop()
         # Priorities match
         self.assertEqual(pri, i)
         # Values match
         self.assertEqual(item, i)

    def alternateRoute(self, num, optimal_path):
        '''To obtain a ranked list of less-than-optimal solutions, the optimal 
        solution must first calculated. This optimal solution is passed in as
        ``optimal_path``. A single edge appearing in the optimal solution is 
        removed from the graph, and the optimum solution to this new graph is 
        calculated. Each edge of the original solution is suppressed in turn
        and a new shortest-path calculated. The secondary solutions are then
        ranked and the ``num`` best sub-optimal solutions are returned. If 
        less than ``num`` solutions exist for the given graph, less than
        ``num`` solutions will be returned. The results are a list of tuples
        of form: 
        ``((cost, path), (cost2, path2), ...)``
        
        An example of finding alternate routes::
        
            search = Pathfinding()
            # find optimal route
            optimal_path = search.shortestPath("A", "E")
            # returns ["A", "C", "E"]
            cost = search.pathCost(optimal_path)
            # returns 3
            alt_paths = search.alternateRoute(2, optimal_path)
            # returns ((4, ["A", "B", "D", "E"]), (4, ["A", "B", "F", "E"]))
        '''
        
        # Store the paths by their weights in a priority queue. The paths with
        # the lowest cost will move to the top. At the end, pop() the queue
        # once for each desired alternative.
        minheap = PriorityQueue()
        
        start, goal = optimal_path[0], optimal_path[-1]
        
        # Don't remove the start or goal nodes
        for i in range(1, len(optimal_path) - 1):
            y = optimal_path[i]
            
            log.info("Look for sub-optimal solution with vertex {} removed".\
                    format(y))
            path = self.shortestPath(start, goal, [y])
            #path = self.shortestPath(start, goal)
            cost = self.pathCost(path)
            
            log.debug("Cost of path with vertex %s removed is %g" \
                                    % (y, cost))
            minheap.push(cost, path)

        alternatives = []
        for i in range(0, min(num, len(minheap))):
            cost, path = minheap.pop()
            alternatives.append((cost,path))
            log.debug("Cost of #%d sub-optimal path is %g" % (i+1, cost))
            
        return alternatives

 def test_neg_priority(self):
     '''Negative priorities'''
     pq = PriorityQueue()
     for i in range(-5, 5):
         pq.push(i,i)
         
     for i in range(-5, 5):
         pri, item = pq.pop()
         # Priorities match
         self.assertEqual(pri, i)
         # Values match
         self.assertEqual(item, i)

class PriorityQueueTest(unittest.TestCase):
    def setUp(self):
        self.p_queue = PriorityQueue()

    def test(self):
        elements = []
        for i in range(1000):
            x = random()
            elements.append(x)
            self.p_queue.insert(x)
        elements.sort(reverse=True)
        for elem in elements:
            self.assertEqual(elem, self.p_queue.pop())

    def FindDirections(self, curState):
        pq = PriorityQueue(["dist", "changeDir"])
        pq.add({"state": curState, "prev": None, "dist": 0 + self.heuristics(curState), "changeDir": 0, "step": 0})
        cnt = 0
        while True:
            elem = pq.pop()
            #print("Dir:", elem["state"].snake.curDir, "step:", elem["step"], "cnt: ", cnt)

            ok_dirs = self._get_ok_dirs_(elem["state"])
            #print ok_dirs
            for d in ok_dirs:
                nextState = elem["state"].GetNextState(d)

                step = elem["step"] + 1
                changeDir = 0
                if d != elem["state"].snake.curDir:
                    changeDir = 1
                dist = step + self.heuristics(nextState)

                pq.add({"state": nextState, "prev": elem, "dist": dist, "changeDir":changeDir, "step": step} )

            #if elem["step"] % 10 == 0:
            #    print elem["step"]
            if pq.IsEmpty():
                print "EMPTY!!!!", elem["step"]
                if len(pq.storage) > 0:
                    elem = pq.storage.pop(0)
                    pq.add(elem)
                """
                while len(pq.storage) > 0:
                    other = pq.storage.pop()
                    print other["step"], elem["step"]
                    if abs(other["step"] - elem["step"]) < elem["step"] * 0.1:
                        break
                        """
                print elem["state"].IsAppleEaten(), elem["state"].apple.GetApplePos()
                #pq.add(other)

            cnt += 1
            if cnt >= 2000 or self._is_goal(elem["state"]) and elem["step"] > 0:
                #print("step:", elem["step"], "cnt:", cnt, "empty:", pq.IsEmpty())
                pq.clean()
                while True:
                    self.directions.append(elem["state"].snake.curDir)
                    elem = elem["prev"]
                    if elem is None:
                        break
                self.directions.pop() # remove the first direction (the state that already take a step)

                return self.directions

def Prim(G, w, s):
	inf = float("inf")
	H = PriorityQueue()
	T = []
	s.priorite = 0
	H.add_task(s, 0)
	i = 1
	for u in G.sommets:
		u.pred = None
		if u != s :
			H.add_task(u, inf)
			u.priorite = inf
	try:
		while True:
			u = H.pop_task()
			u.couleur = "noir"
			if u.priorite != inf:
				if u.pred is not None: T.append((u.pred, u))
				for v in u.voisins:
					if v.couleur == "blanc": #v n'est pas sorti du tas
						if w[(u, v)] < v.priorite:
							v.priorite = w[(u, v)]
							H.add_task(v, v.priorite)
							v.pred = u
	except:
		pass
	return T

 def shortest_path(self, target):
     """
     Uses Dijkstra's algorithm to return the shortest paths between the 
     target and all other nodes in the graph.
     """
     if not self.weighted:
         print "Graph is not weighted; redirecting to BFS"
         return self.bfs(target, min_distance=True)
     distances_pq = PriorityQueue("min")
     distances_dict = {} 
     unvisited = []
     for node in self.adj_matrix[0]:
         if node == target:
             distances_pq.enqueue(0, node)
             distances_dict[node] = 0
         elif node != False:
             distances_pq.enqueue(float('inf'), node)
             distances_dict[node] = float('inf')
         else:
             continue
         unvisited.append(node)
     while unvisited:
         min_distance, min_node = distances_pq.dequeue()
         if min_node not in unvisited:
             continue
         neighbors = self.linked(min_node)
         for neighbor in neighbors:
             neighbor_distance = min(distances_dict[neighbor], 
                                     min_distance + self.link_weight(min_node, neighbor))
             if neighbor_distance != distances_dict[neighbor]:
                distances_dict[neighbor] = neighbor_distance
                distances_pq.enqueue(neighbor_distance, neighbor)
         unvisited.remove(min_node)
     return distances_dict

    def FindDirections(self, curState):
        self.directions = []
        pq = PriorityQueue(["dist"])
        maxDepth = 5
        pq.add({"state": curState, "dist": self.heuristics(curState), "step": 0, "prev": None})
        cnt = 0
        while not pq.IsEmpty():
            elem = pq.pop()
            state = elem["state"]
            stack = []
            stack.append({"state": state, "step": 0, "prev": elem["prev"]})

            """
            if cnt >= SCREEN_WITH + SCREEN_HEIGHT - 4 * SNAKE_WITH_HALH - 2:
                print "size of queue: ", len(pq.queue)
                cnt = 0
            """
            """
            maxSize = max(len(pq.queue) / 2, len(pq.queue) - randint(10, 20))
            reduceSize = min(maxSize, len(pq.queue) - 5)
            for i in range(reduceSize):
                pq.pop()

            """
            if len(pq.queue) > 700:
                # TODO: if we cannnot find solution for so long a time, the size of queue should
                # be reduced to a pretty small number
                for i in range(randint(0,len(pq.queue)-1)):
                    pq.pop()
                #print "size of queue: ", len(pq.queue)
                #print curState.snake.body
                #print curState.snake.GetBodyRects()
                continue

            while len(stack) > 0:
                el = stack.pop()
                stat = el["state"]

                if el["step"] >= maxDepth:
                    pq.add({"state": stat, "dist": self.heuristics(stat), "step": el["step"], "prev": el["prev"]})
                    continue

                if stat.IsAppleEaten():
                    # guess if the snake can be dead by instinct
                    stat.AddSnakeLen()
                    if self._is_possible_dead_(stat):
                        continue
                    while el is not None:
                        self.directions.append(el["state"].snake.curDir)
                        el = el["prev"]
                    self.directions.pop()
                    return

                ok_dirs = self._arange_dirs_(stat, self._get_ok_dirs_(stat))
                for d in ok_dirs:
                    nextStat = stat.GetNextState(d)
                    nextEl = {"state": nextStat, "step": el["step"]+1, "prev": el}
                    stack.append(nextEl)

        self.directions.append(Direction.Stop)

def dijkstrasAlgorithm(graph, start):
    for v in graph:
        v.setStatus(0)
        
    #start.setStatus(2)
    start.setDistance(0)
    pq = PriorityQueue()
    #heapq.heappush(pq, (0, start))
    pq.enQueue((0, start))
    while (not pq.isEmpty()):
        current = pq.deQueue()[1]
        current.setStatus(2)
        #if(current.getParent() != None):
            #  print(str(current.getParent().getId()) + "->" + str(current.getId()))
        for neighbour in current.getNeighbours():
            if (neighbour.getStatus() == 0):        
                neighbour.setStatus(1)
                neighbour.setParent(current)
                neighbour.setpqWeight(current.neighbours[neighbour])
                neighbour.setDistance(current.getDistance() + current.neighbours[neighbour])
                pq.enQueue((neighbour.getpqWeight(), neighbour))
            elif (neighbour.getStatus() == 1):
                if (neighbour.getDistance()) > (current.getDistance() + current.neighbours[neighbour]):
                    #old = (neighbour.getpqWeight(), neighbour)
                    #neighbour.setpqWeight(current.neighbours[neighbour])
                    #pq.updatePriority(old, (neighbour.getpqWeight(), neighbour))
                    neighbour.setParent(current)
                    neighbour.setDistance(current.getDistance() + current.neighbours[neighbour])