def performUCS(self, position, goal):
to_explore = PriorityQueue()
explored = set()
prevNode = dict({position: 0})
to_explore.push(position, 0)
while (not(to_explore.is_empty())):
aux = to_explore.pop()
node = aux[0]
prevCost = aux[1]
to_explore.remove(node)
if (goal == node):
return prevNode
explored.add(node)
actions = ['N','S','E','W']
for action in actions:
child, actionCost = self.step(node, action)
if not(child == node):
cost = prevCost + actionCost
if not(child in explored or child in to_explore):
to_explore.push(child, cost)
prevNode[child] = (node, action)
elif child in to_explore and cost < to_explore.getCost(child):
to_explore.update(child, cost)
prevNode[child] = (node, action)
return None
def performAStar(self, position, goal):
to_explore = PriorityQueue()
explored = set()
prevNode = dict({position: 0})
costs = dict({position: 0})
to_explore.push(position, 0 + self.model.h(position, goal))
stepCounter = 0
while (not (to_explore.is_empty())):
node = to_explore.pop()[0]
to_explore.remove(node)
if (goal == node):
return prevNode
explored.add(node)
actions = ['N', 'S', 'E', 'W']
for action in actions:
child, actionCost = self.step(node, action)
if not (child == node):
prevCost = costs[node] + actionCost
cost = prevCost + self.model.h(child, goal)
if not (child in explored or child in to_explore):
to_explore.push(child, cost)
costs[child] = prevCost
prevNode[child] = (node, action)
elif child in to_explore and cost < to_explore.getCost(
child):
to_explore.update(child, cost)
costs[child] = prevCost
prevNode[child] = (node, action)
return None
