def search(queue, initialState, factory, goalTest, maxdepth=float('inf'), maxcost=float('inf')) :
closedList = {}
nodesEnqueued = 1
nodesDequeued = 0
nodesExpanded = 0
queue.insert(initialState)
### you complete this.
### While there are states in the queue,
### 1. Dequeue
### 2. If this is the goal, stop
### 3. If not, insert in the closed list and generate successors
### 4. If successors are not in the closed list, enqueue them.
found = False
while not queue.isEmpty():
current_state = queue.pop()
nodesDequeued += 1
if current_state.isGoal(goalTest):
found = True
break
newf = searchQueues.f(current_state, goal_vertex)
if (current_state.depth >= maxdepth) or (newf > maxcost):
successors = []
if newf < queue.mincost : queue.mincost = newf
else:
successors = factory.successors(current_state)
closedList[current_state.vertex.name] = current_state
nodesExpanded += len(successors)
for succ_state in successors:
if (not succ_state.vertex.name in closedList) or (closedList[succ_state.vertex.name] > succ_state):
queue.insert(succ_state)
nodesEnqueued += 1
if not found:
print "Search failed!"
print "============================="
return found
print "nodes enqueued: %s" % nodesEnqueued
print "nodes dequeued: %s" % nodesDequeued
print "nodes expanded: %s" % nodesExpanded
printSolution(current_state)
# Find the max depth in closedList
max_depth = 0
for name, state in closedList.iteritems():
if state.depth > max_depth: max_depth = state.depth
print "search max depth: %s" % max_depth
print "============================="
return found
# init node
init_vertex = graph.vertex_list[args.initialState]
init_state = Node(init_vertex, None, 0, 0)
goal_name = args.goal # [Hack] Global var for goalTest()
goal_vertex = graph.vertex_list[goal_name]
if args.search != 'IDAStar': queue = getattr(searchQueues, args.search + 'Queue')(goal_vertex)
factory = NodeFactory(graph)
if args.search == 'DFS':
if args.isIterative:
print "Searching from %s to %s by %s iteratively with %s limit..." % (args.initialState, args.goal, args.search, args.depthLimit)
depth_limit = min(args.depthLimit, len(graph.vertex_list))
for depth_limit in range(0, depth_limit):
print "Now trying with depth limit %s..." % (depth_limit)
if search(queue, init_state, factory, goalTest, depth_limit): break
else:
print "Searching from %s to %s by %s with depth limit %s..." % (args.initialState, args.goal, args.search, args.depthLimit)
search(queue, init_state, factory, goalTest, maxdepth=args.depthLimit)
elif args.search == 'IDAStar':
f = searchQueues.f(init_state, goal_vertex)
print "Searching from %s to %s by %s with depth limit %s and cost limit %f..." % (args.initialState, args.goal, args.search, args.depthLimit, f)
while True:
print "Now trying with cost limit %f..." % f
queue = searchQueues.DFSQueue(goal_vertex)
res = search(queue, init_state, factory, goalTest, maxdepth=args.depthLimit, maxcost=f)
if (res) or (queue.mincost == float('inf')): break
f = queue.mincost
else:
print "Searching from %s to %s by %s..." % (args.initialState, args.goal, args.search)
search(queue, init_state, factory, goalTest)