def g(cls, parentnode: Node, action, childnode: Node):
return len(childnode.path())
def graph_search(problem, verbose=False, debug=False):
"""graph_search(problem, verbose, debug) - Given a problem representation
(instance of basicsearch_lib02.representation.Problem or derived class),
attempt to solve the problem.
If debug is True, debugging information will be displayed.
if verbose is True, the following information will be displayed:
Number of moves to solution
List of moves and resulting puzzle states
Example:
Solution in 25 moves
Initial state
0 1 2
0 4 8 7
1 5 . 2
2 3 6 1
Move 1 - [0, -1]
0 1 2
0 4 8 7
1 . 5 2
2 3 6 1
Move 2 - [1, 0]
0 1 2
0 4 8 7
1 3 5 2
2 . 6 1
... more moves ...
0 1 2
0 1 3 5
1 4 2 .
2 6 7 8
Move 22 - [-1, 0]
0 1 2
0 1 3 .
1 4 2 5
2 6 7 8
Move 23 - [0, -1]
0 1 2
0 1 . 3
1 4 2 5
2 6 7 8
Move 24 - [1, 0]
0 1 2
0 1 2 3
1 4 . 5
2 6 7 8
If no solution were found (not possible with the puzzles we
are using), we would display:
No solution found
Returns a tuple (path, nodes_explored) where:
path - list of actions to solve the problem or None if no solution was found
nodes_explored - Number of nodes explored (dequeued from frontier)
"""
rootNode = Node(problem, problem.initial)
frontier = PriorityQueue()
frontier.append(rootNode)
frontierHash = {}
frontierHash[hash(rootNode)] = rootNode
done = found = False
exploredNodes = Explored()
while not done:
node = frontier.pop()
frontierHash.pop(hash(node), None)
#print(node)
exploredNodes.add(node)
if node.problem.goal_test(node.state):
found = done = True
#print("finished with solution")
else:
nodes = []
for n in node.expand(node.problem):
#may need to come back and compare boards instead of nodes
if (hash(n) not in frontierHash or frontierHash[hash(n)] != n
) and exploredNodes.exists(n) == False:
#print("adding to the frontier")
nodes.append(n)
for n in nodes:
frontier.append(n)
frontierHash[hash(n)] = n
if len(frontier) == 0:
print("finished, no solution")
done = True
if verbose == True:
#print the path to the solution
if found:
path = node.path()
solution = node.solution()
print("Solution in ", len(solution), "moves")
print("Initial state")
counter = 1
for item in path:
print(item.state)
if counter <= len(solution):
print("Move ", counter, " - ", solution[counter - 1])
counter = counter + 1
else:
print("No solution found")
if found == True:
return (node.solution(), len(node.path()))
else:
return (None, None)
def graph_search(problem, verbose=False, debug=False):
"""graph_search(problem, verbose, debug) - Given a problem representation
(instance of basicsearch_lib02.representation.Problem or derived class),
attempt to solve the problem.
If debug is True, debugging information will be displayed.
if verbose is True, the following information will be displayed:
Number of moves to solution
List of moves and resulting puzzle states
Example:
Solution in 25 moves
Initial state
0 1 2
0 4 8 7
1 5 . 2
2 3 6 1
Move 1 - [0, -1]
0 1 2
0 4 8 7
1 . 5 2
2 3 6 1
Move 2 - [1, 0]
0 1 2
0 4 8 7
1 3 5 2
2 . 6 1
... more moves ...
0 1 2
0 1 3 5
1 4 2 .
2 6 7 8
Move 22 - [-1, 0]
0 1 2
0 1 3 .
1 4 2 5
2 6 7 8
Move 23 - [0, -1]
0 1 2
0 1 . 3
1 4 2 5
2 6 7 8
Move 24 - [1, 0]
0 1 2
0 1 2 3
1 4 . 5
2 6 7 8
If no solution were found (not possible with the puzzles we
are using), we would display:
No solution found
Returns a tuple (path, nodes_explored, elapsed_s) where:
path - list of actions to solve the problem or None if no solution was found
nodes_explored - Number of nodes explored (dequeued from frontier)
elapsed_s is the elapsed wall clock time performing the search
"""
# Start the timer:
timer = Timer()
# Create a hashtable to store all explored states
exploredStates = Explored()
# Create a PriorityQueue to store all current states
frontier = PriorityQueue(f=lambda node: node.g + node.h)
# Initialize the frontier with the first Node
frontier.append(Node(problem, problem.initial))
# Loop until the solution is found or the state space is exhausted
while frontier.__len__() != 0:
# Pop a node from the frontier
node = frontier.pop()
if problem.goal_test(node.state):
alpha = node.path()
actions = node.solution()
# If verbose is True, display all moves
if verbose:
print(f'Solution in {len(actions)} moves')
for i in range(len(actions)):
print(f'Move {i + 1} - {actions[i]}')
print(alpha[i + 1].state, end='\n\n')
# Return a Tuple contains:
# - List of actions to solve the problem,
# - Number of nodes explored,
# - elapsed_s in seconds
return alpha, len(exploredStates.exploredStates), timer.elapsed_s()
else:
# Explore the children of current node
for child in node.expand(problem):
child_tuple = child.state.state_tuple()
# if we haven't explored this child yet
# Load it into frontier and explore set
if not exploredStates.exists(child_tuple):
exploredStates.add(child_tuple)
frontier.append(child)
# If no solution found, return None
return None
def graph_search(problem, verbose=False, debug=False):
"""graph_search(problem, verbose, debug) - Given a problem representation
(instance of basicsearch_lib02.representation.Problem or derived class),
attempt to solve the problem.
If debug is True, debugging information will be displayed.
if verbose is True, the following information will be displayed:
Number of moves to solution
List of moves and resulting puzzle states
Example:
Solution in 25 moves
Initial state
0 1 2
0 4 8 7
1 5 . 2
2 3 6 1
Move 1 - [0, -1]
0 1 2
0 4 8 7
1 . 5 2
2 3 6 1
Move 2 - [1, 0]
0 1 2
0 4 8 7
1 3 5 2
2 . 6 1
... more moves ...
0 1 2
0 1 3 5
1 4 2 .
2 6 7 8
Move 22 - [-1, 0]
0 1 2
0 1 3 .
1 4 2 5
2 6 7 8
Move 23 - [0, -1]
0 1 2
0 1 . 3
1 4 2 5
2 6 7 8
Move 24 - [1, 0]
0 1 2
0 1 2 3
1 4 . 5
2 6 7 8
If no solution were found (not possible with the puzzles we
are using), we would display:
No solution found
Returns a tuple (path, nodes_explored) where:
path - list of actions to solve the problem or None if no solution was found
nodes_explored - Number of nodes explored (dequeued from frontier)
"""
#Initial tileboard for testing
tb = problem.initial
#Create first node and test if node passes goal
node0 = Node(problem, tb)
if problem.goal_test(node0.state) == True:
return node0.solution()
#define frontier set as priority queue and the explored set
pq = PriorityQueue()
pq.append(node0)
new_nodes = []
exploredSet = Explored()
frontier = Explored()
frontier.add(node0)
nodesExpanded = 0
#Expand the search tree until the goal state is found
found = False
#time.sleep(2)
while (not found):
#Check if the frontier is empty signifying failure
if pq.__len__() == 0:
print("No solution found")
break
#Take the next node from the priority queue and add it to explored set
node = pq.pop()
exploredSet.add(node)
#Check if the goal state has been found
if problem.goal_test(node.state) == True:
path = node.path()
solution = node.solution()
steps = len(path) - 1
found = True
if verbose == True:
verboseFunc(solution, steps, tb, path)
else:
#Expand the search tree and check if the nodes have been explored
new_nodes = node.expand(problem)
for j in range(len(new_nodes)):
if exploredSet.exists(new_nodes[j].state) or frontier.exists(
new_nodes[j].state):
continue
else:
#Add one to the number of nodes explored
nodesExpanded += 1
pq.append(new_nodes[j]) #Add the nodes to the priority queue
frontier.add(
new_nodes[j]) #use hashed set to decrease lookup time
if debug == True:
debugFunc(debug, pq)
return (steps, nodesExpanded)
def graph_search(problem, verbose=False, debug=False):
"""graph_search(problem, verbose, debug) - Given a problem representation
(instance of basicsearch_lib02.representation.Problem or derived class),
attempt to solve the problem.
If debug is True, debugging information will be displayed.
if verbose is True, the following information will be displayed:
Number of moves to solution
List of moves and resulting puzzle states
Example:
Solution in 25 moves
Initial state
0 1 2
0 4 8 7
1 5 . 2
2 3 6 1
Move 1 - [0, -1]
0 1 2
0 4 8 7
1 . 5 2
2 3 6 1
Move 2 - [1, 0]
0 1 2
0 4 8 7
1 3 5 2
2 . 6 1
... more moves ...
0 1 2
0 1 3 5
1 4 2 .
2 6 7 8
Move 22 - [-1, 0]
0 1 2
0 1 3 .
1 4 2 5
2 6 7 8
Move 23 - [0, -1]
0 1 2
0 1 . 3
1 4 2 5
2 6 7 8
Move 24 - [1, 0]
0 1 2
0 1 2 3
1 4 . 5
2 6 7 8
If no solution were found (not possible with the puzzles we
are using), we would display:
No solution found
Returns a tuple (path, nodes_explored) where:
path - list of actions to solve the problem or None if no solution was found
nodes_explored - Number of nodes explored (dequeued from frontier)
"""
frontierNodes = PriorityQueue(min, Node.get_f)
node = Node(problem, problem.getInitialBoardState())
nodesExplored = 0
exploredStates = Explored() #hash table to store states
exploredStates.add(node)
for node in node.expand(problem):
if not exploredStates.exists(node): #its not a duplicate in explored
frontierNodes.append(node) #get initial frontier nodes
done = found = False
while not done:
node = frontierNodes.pop() #loop thru frontier states
nodesExplored += 1
exploredStates.add(node)
if problem.goal_test(node.state): #if found, set true
found = done = True
else: #if not, then add the new frontier states to the queue
for node in node.expand(problem):
if not exploredStates.exists(
node): #its not a duplicate in explored
#if not frontierNodes.__contains__(node): #not a duplicate in frontier, slow!
frontierNodes.append(node)
if (frontierNodes.__len__ == 0
): #if we run thru all frontier, search complete
done = True
if found:
if (verbose):
print("Moves to solution: ", node.path().__len__())
print("Nodes Expanded: ", nodesExplored)
move = 0
solutionList = node.solution()
boardList = []
for node in node.path():
boardList.append(problem.generateDebugBoard(node.state))
print("Initial State")
for board in boardList:
counter = move + 1
print(board)
print()
if (move < boardList.__len__() - 1):
print("Move ", counter, " ", solutionList[move])
move += 1
if (debug):
print()
print("Debug Info:")
print(print_nodes(node.path()))
print()
return (node.solution(), nodesExplored
) #returns solution node's path/solution
else:
if (verbose | debug):
print("No solution found")
return ("No solution found", nodesExplored)
def graph_search(problem, verbose=False, debug=False):
"""graph_search(problem, verbose, debug) - Given a problem representation
(instance of basicsearch_lib02.representation.Problem or derived class),
attempt to solve the problem.
If debug is True, debugging information will be displayed.
if verbose is True, the following information will be displayed:
Number of moves to solution
List of moves and resulting puzzle states
Example:
Solution in 25 moves
Initial state
0 1 2
0 4 8 7
1 5 . 2
2 3 6 1
Move 1 - [0, -1]
0 1 2
0 4 8 7
1 . 5 2
2 3 6 1
Move 2 - [1, 0]
0 1 2
0 4 8 7
1 3 5 2
2 . 6 1
... more moves ...
0 1 2
0 1 3 5
1 4 2 .
2 6 7 8
Move 22 - [-1, 0]
0 1 2
0 1 3 .
1 4 2 5
2 6 7 8
Move 23 - [0, -1]
0 1 2
0 1 . 3
1 4 2 5
2 6 7 8
Move 24 - [1, 0]
0 1 2
0 1 2 3
1 4 . 5
2 6 7 8
If no solution were found (not possible with the puzzles we
are using), we would display:
No solution found
Returns a tuple (path, nodes_explored) where:
path - list of actions to solve the problem or None if no solution was found
nodes_explored - Number of nodes explored (dequeued from frontier)
"""
start = time.time()
initial_node = Node(problem, problem.initial)
node_queue = PriorityQueue(f=lambda x: x.get_f())
explore = Explored()
explore.add(initial_node.state)
node_num = 1
node = initial_node
board = problem.initial
solved = board.solved()
while (not solved):
newNodes = node.expand(problem)
#Insert all new nodes into queues and explored
for newNode in newNodes:
if (not explore.exists(newNode.state)):
explore.add(newNode.state)
node_queue.append(newNode)
node_num += 1
if newNode.state.solved():
node = newNode
solved = newNode.state.solved()
if len(node_queue) == 0:
break
if not solved:
node = node_queue.pop()
board = newNode.state
second = (time.time() - start)
actions = [a_node.action for a_node in node.path() if a_node.action]
return (actions, node_num, second)
def graph_search(problem, verbose=False, debug=False):
"""graph_search(problem, verbose, debug) - Given a problem representation
(instance of basicsearch_lib02.representation.Problem or derived class),
attempt to solve the problem.
If debug is True, debugging information will be displayed.
if verbose is True, the following information will be displayed:
Number of moves to solution
List of moves and resulting puzzle states
Example:
Solution in 25 moves
Initial state
0 1 2
0 4 8 7
1 5 . 2
2 3 6 1
Move 1 - [0, -1]
0 1 2
0 4 8 7
1 . 5 2
2 3 6 1
Move 2 - [1, 0]
0 1 2
0 4 8 7
1 3 5 2
2 . 6 1
... more moves ...
0 1 2
0 1 3 5
1 4 2 .
2 6 7 8
Move 22 - [-1, 0]
0 1 2
0 1 3 .
1 4 2 5
2 6 7 8
Move 23 - [0, -1]
0 1 2
0 1 . 3
1 4 2 5
2 6 7 8
Move 24 - [1, 0]
0 1 2
0 1 2 3
1 4 . 5
2 6 7 8
If no solution were found (not possible with the puzzles we
are using), we would display:
No solution found
Returns a tuple (path, nodes_explored) where:
path - list of actions to solve the problem or None if no solution was found
nodes_explored - Number of nodes explored (dequeued from frontier)
"""
#generate initial state, no parent/actions
#based off of graph search example on slides
node = Node(problem, problem.initial)
if (problem.g == DepthFirst.g and problem.h == DepthFirst.h):
frontierset = PriorityQueue(node.get_f())
else:
frontierset = PriorityQueue()
frontierset.append(node)
done = False
exploredset = Explored()
expanded = 0 #number of expansions
while not done:
node = frontierset.pop()
#print(node.__repr__())
exploredset.add(node.state)
if problem.goal_test(node.state):
done = True
else:
for nextaction in node.expand(problem):
expanded += 1
if not exploredset.exists(nextaction.state):
frontierset.append(nextaction)
done = frontierset.__len__() == 0
if verbose:
if (len(node.solution()) == 0): #No solutions found
print("No solution found")
else:
print("Solution in ", len(node.solution()), " moves")
print("Initial State")
print(problem.initial)
tempboard = problem.initial
for i in range(0, len(node.solution())):
print("Move ", i + 1, " - ", node.solution()[i])
tempboard = tempboard.move(node.solution()[i])
print(tempboard.__repr__())
return (node.solution(), expanded)
def graph_search(problem, verbose=False, debug=False):
"""graph_search(problem, verbose, debug) - Given a problem representation
attempt to solve the problem.
Returns a tuple (path, nodes_explored) where:
path - list of actions to solve the problem or None if no solution was found
nodes_explored - Number of nodes explored (dequeued from frontier)
"""
frontier = PriorityQueue()
root = Node(problem, problem.initial)
frontier.append(root)
node = frontier.pop()
pop = True # for right pop left pop for BFS
if node.expand(node.problem)[0].g < 0:
# DFS which has the negative depth
# since start from the deepest node
frontier = deque()
frontier.append(root)
elif node.expand(node.problem)[0].h == 2:
# BFS
pop = False
frontier = deque()
frontier.append(root)
else:
# Manhattan
frontier.append(node)
DONE = False
nodes_explored = 0
explored_set = Explored()
while not DONE:
if pop:
node = frontier.pop() # DFS A*
else:
node = frontier.popleft() # BFS
if debug:
print("Next decision is:", str(node))
explored_set.add(node.state.state_tuple())
nodes_explored += 1
if problem.goal_test(node.state):
solved_path = node.path()
if debug:
print("Puzzle solved")
# print("path:", str(node.path()))
DONE = True
# if Verbose True display the info stats in requirement
if verbose:
print("Solution in %d moves" % (len(solved_path) - 1))
print("Initial State")
print(solved_path[0])
for i in range(1, len(solved_path)):
print("Move %d - %s" % (i, solved_path[i].action))
print(solved_path[i].state)
return solved_path, nodes_explored
# Not solved yet
else:
for child in node.expand(node.problem):
# add new child to frontier set
if not explored_set.exists(child.state.state_tuple()):
frontier.append(child)
explored_set.add(child)
# finish when there is no node in the queue
# if debug:
# print("Num node in quenue:", str(len(frontier)))
DONE = len(frontier) == 0
if verbose:
print("No solution found")
return None, nodes_explored
def graph_search(problem, verbose=False, debug=False):
"""graph_search(problem, verbose, debug) - Given a problem representation
(instance of basicsearch_lib02.representation.Problem or derived class),
attempt to solve the problem.
If debug is True, debugging information will be displayed.
if verbose is True, the following information will be displayed:
Number of moves to solution
List of moves and resulting puzzle states
Example:
Solution in 25 moves
Initial state
0 1 2
0 4 8 7
1 5 . 2
2 3 6 1
Move 1 - [0, -1]
0 1 2
0 4 8 7
1 . 5 2
2 3 6 1
Move 2 - [1, 0]
0 1 2
0 4 8 7
1 3 5 2
2 . 6 1
... more moves ...
0 1 2
0 1 3 5
1 4 2 .
2 6 7 8
Move 22 - [-1, 0]
0 1 2
0 1 3 .
1 4 2 5
2 6 7 8
Move 23 - [0, -1]
0 1 2
0 1 . 3
1 4 2 5
2 6 7 8
Move 24 - [1, 0]
0 1 2
0 1 2 3
1 4 . 5
2 6 7 8
If no solution were found (not possible with the puzzles we
are using), we would display:
No solution found
Returns a tuple (path, nodes_explored) where:
path - list of actions to solve the problem or None if no solution was found
nodes_explored - Number of nodes explored (dequeued from frontier)
"""
# Create explored set and initialize variable to track nodes expanded
explored = Explored()
frontier = Explored()
frontierQ = PriorityQueue()
nodes_expanded = 0
# Create initial node as starting point and add to frontier
initial_node = Node(problem, problem.puzzle.state_tuple())
frontierQ.append(initial_node)
frontier.add(initial_node.state)
node = None
# Run while loop until graph search is complete
done = found = False
while not done:
# Pop next node from frontier priority queue
node = frontierQ.pop()
if debug:
print("Node:", node, "Action", node.action) # View node for debugging purposes
# Add current node state to explored set
state = node.state
explored.add(state)
if problem.goal_test(state):
# If goal found, exit while loop and return
found = done = True
else:
# If goal not found, loop through possible actions depending on state
for act in problem.actions(state):
next_state = problem.result(state, act)
next_node = node.child_node(act)
# Check if next node after action is in frontier queue or explored set
if not explored.exists(next_state) and not frontier.exists(next_state):
# If not, add to frontier and track the node as expanded
frontier.add(next_state)
frontierQ.append(next_node)
nodes_expanded += 1
if not found:
done = len(frontierQ) <= -1 # Exit loop if frontier is empty
if not found:
print("No solution found.")
# This should not happen, we check if board is solvable in Tileboard class
else:
if verbose:
# If verbose, print puzzle states and actions in path to solution
print("Solution in", len(node.solution()), "moves")
print(problem.puzzle)
# Loop through each action in path
for i, act in enumerate(node.solution()):
problem.puzzle = problem.puzzle.move(act)
# Display move taken and resulting puzzle board
print("Move", i + 1, "-", act)
print(problem.puzzle)
if debug:
print("*" * 10, "Win") # Divider for visualization during debugging
return node.solution(), nodes_expanded
def graph_search(problem: Problem, verbose=False, debug=False):
"""graph_search(problem, verbose, debug) - Given a problem representation
(instance of basicsearch_lib02.representation.Problem or derived class),
attempt to solve the problem.
If debug is True, debugging information will be displayed.
if verbose is True, the following information will be displayed:
Number of moves to solution
List of moves and resulting puzzle states
Example:
Solution in 25 moves
Initial state
0 1 2
0 4 8 7
1 5 . 2
2 3 6 1
Move 1 - [0, -1]
0 1 2
0 4 8 7
1 . 5 2
2 3 6 1
Move 2 - [1, 0]
0 1 2
0 4 8 7
1 3 5 2
2 . 6 1
... more moves ...
0 1 2
0 1 3 5
1 4 2 .
2 6 7 8
Move 22 - [-1, 0]
0 1 2
0 1 3 .
1 4 2 5
2 6 7 8
Move 23 - [0, -1]
0 1 2
0 1 . 3
1 4 2 5
2 6 7 8
Move 24 - [1, 0]
0 1 2
0 1 2 3
1 4 . 5
2 6 7 8
If no solution were found (not possible with the puzzles we
are using), we would display:
No solution found
Returns a tuple (path, nodes_explored) where:
path - list of actions to solve the problem or None if no solution was found
nodes_explored - Number of nodes explored (dequeued from frontier)
"""
# Establish frontier set and nodes
frontier = PriorityQueue()
frontier.append(Node(problem, problem.initial))
node = frontier.pop()
popping = True
if node.expand(node.problem)[0].g < 0:
# Depth First Search
frontier = deque()
frontier.append(Node(problem, problem.initial))
elif node.expand(node.problem)[0].h < 2:
# Breadth First Search
popping = False
frontier = deque()
frontier.append(Node(problem, problem.initial))
else:
# Manhattan Search
frontier.append(node)
# Working with the hash
frontier_hash = Explored()
frontier_hash.add(problem.initial.state_tuple())
finished = False
nodes_explored = 0
explored = Explored()
while not finished:
if popping:
node = frontier.pop() # Manhattan and DFS
else:
node = frontier.popleft() # BFS
if debug:
print("Node popped:", str(node))
explored.add(node.state.state_tuple())
nodes_explored += 1
if node.state.solved():
if debug:
print("Solution found!")
solution_path = node.path()
finished = True
if verbose:
print_solution(solution_path)
return solution_path, nodes_explored
else:
for child in node.expand(node.problem):
if not explored.exists(child.state.state_tuple(
)) and not frontier_hash.exists(child.state.state_tuple()):
frontier.append(child)
frontier_hash.add(child)
elif debug:
print("Skipping...", child)
pass
finished = len(frontier) == 0
if debug:
print("")
if verbose:
print("No solution found")
return None, nodes_explored
def graph_search(problem, verbose=False, debug=False):
"""graph_search(problem, verbose, debug) --
Given a problem representation (instance of basicsearch_lib02.representation.
Problem or derived class), attempt to solve the problem.
If debug is True, debugging information will be displayed.
if verbose is True, the following information will be displayed:
Number of moves to solution
List of moves and resulting puzzle states
Example:
Solution in 25 moves
Initial state
0 1 2
0 4 8 7
1 5 . 2
2 3 6 1
Move 1 - [0, -1]
0 1 2
0 4 8 7
1 . 5 2
2 3 6 1
Move 2 - [1, 0]
0 1 2
0 4 8 7
1 3 5 2
2 . 6 1
... more moves ...
0 1 2
0 1 3 5
1 4 2 .
2 6 7 8
Move 22 - [-1, 0]
0 1 2
0 1 3 .
1 4 2 5
2 6 7 8
Move 23 - [0, -1]
0 1 2
0 1 . 3
1 4 2 5
2 6 7 8
Move 24 - [1, 0]
0 1 2
0 1 2 3
1 4 . 5
2 6 7 8
If no solution were found (not possible with the puzzles we
are using), we would display:
No solution found
Returns a tuple (path, nodes_explored) where:
path - list of actions to solve the problem or None if no solution was found
nodes_explored - Number of nodes explored (dequeued from frontier)
"""
# PriorityQueue should be used to maintain the order of the queue.
frontier = PriorityQueue()
frontier.append(Node(problem, problem.initial))
current_node = frontier.pop()
p = True
#depth first search
if current_node.expand(current_node.problem)[0].g < 0:
frontier = deque()
frontier.append(Node(problem, problem.initial))
#breadth first search
elif current_node.expand(current_node.problem)[0].h < 2:
p = False
frontier = deque()
frontier.append(Node(problem, problem.initial))
#manhattan
else:
frontier.append(current_node)
f_hash = Explored()
f_hash.add(problem.initial.state_tuple())
done = False
n_explored = 0
explored = Explored()
#graph_search
while not done:
if p:
current_node = frontier.pop()
else:
current_node = frontier.popleft()
explored.add(current_node.state.state_tuple())
n_explored = n_explored + 1 #inc the number of explored nodes
if current_node.state.solved():
path = current_node.path()
done = True
return path, n_explored
#if not found in the tree return none and number of nodes explored
else:
for child in current_node.expand(current_node.problem):
if not explored.exists(child.state.state_tuple()) and not \
f_hash.exists(child.state.state_tuple()):
frontier.append(child)
f_hash.add(child)
done = len(frontier) == 0
return None, n_explored
def graph_search(problem, verbose=False, debug=False):
"""graph_search(problem, verbose, debug) - Given a problem representation
(instance of basicsearch_lib02.representation.Problem or derived class),
attempt to solve the problem.
If debug is True, debugging information will be displayed.
if verbose is True, the following information will be displayed:
Number of moves to solution
List of moves and resulting puzzle states
Example:
Solution in 25 moves
Initial state
0 1 2
0 4 8 7
1 5 . 2
2 3 6 1
Move 1 - [0, -1]
0 1 2
0 4 8 7
1 . 5 2
2 3 6 1
Move 2 - [1, 0]
0 1 2
0 4 8 7
1 3 5 2
2 . 6 1
... more moves ...
0 1 2
0 1 3 5
1 4 2 .
2 6 7 8
Move 22 - [-1, 0]
0 1 2
0 1 3 .
1 4 2 5
2 6 7 8
Move 23 - [0, -1]
0 1 2
0 1 . 3
1 4 2 5
2 6 7 8
Move 24 - [1, 0]
0 1 2
0 1 2 3
1 4 . 5
2 6 7 8
If no solution were found (not possible with the puzzles we
are using), we would display:
No solution found
Returns a tuple (path, nodes_explored, elapsed_s) where:
path - list of actions to solve the problem or None if no solution was found
nodes_explored - Number of nodes explored (dequeued from frontier)
elapsed_s is the elapsed wall clock time performing the search
"""
"""
uses a priority queue for the frontier and an instance of the Explored class for
the explored set
"""
# list of actions to solution
t = Timer() # starts the timer
frontier = PriorityQueue(
) # we are always going to have a frontier and we always need to put in to priority queue
explored = Explored() # explored set, NOT REALLY A SET, it is a dictionary
frontier.append(Node(problem,
problem.initial)) # add initial node to the frontier
solution = None
i = 0 # used for debug and verbose purposes
while (frontier.__len__() > 0):
current = frontier.pop() # Dequeue current node
if (debug == True and i % 100000 == 0):
print("############# %d #################" %
i) # display iteration number
print(current.state) # display current node
print("nodes in frontier",
frontier.__len__()) # display lenght of frontier set
print("time elapsed %dmin %dsec" %
(t.elapsed_s() / 60,
t.elapsed_s() % 60)) # display time elapsed
explored.add(current.state) # add current state to explored
if problem.goal_test(
current.state): # if the current state is the goal
if debug: # used for debugging
print(
"###goal found, i = %d ###" % i
) # display the iteration number for when the goal was found
print(current.state) # display current node
print("length",
len(current.path())) # display current node path length
print("time elapsed %dmin %dsec" %
(t.elapsed_s() / 60,
t.elapsed_s() % 60)) # display time elapsed
solution = current # found goal and end loop
break
else:
child_nodes = current.expand(
problem) # expand the state to find child nodes
for child in child_nodes:
if not explored.exists(
child.state
): # if we haven't encountered the states yet
frontier.append(child) # add it to the frontier
explored.add(
child.state
) # add to explored to prevent duplication in frontier
i = i + 1 # used for debug and verbose purposes
if solution != None and verbose == True: # if we found a solution and want more detail
solution_path = solution.path() # create list of nodes to solution
num_moves = len(solution_path) - 1 # number of moves to goal
print("############# %d #################" % i)
print("Solution in ", num_moves, " moves.\n") # heading of detail
print("Intial state")
print(solution_path[0]) # first state printed
print("time elapsed %dmin %dsec" %
(t.elapsed_s() / 60, t.elapsed_s() % 60)) # display time elapsed
for i in range(1, len(solution_path)): # print each move in order
print("\nMove ", i, "") # display move number
print(solution_path[i]) # display move
if solution == None: # no solution found
print("no solution found")
path = [] # if no solution found return empty list
return (
path, len(explored.explored_set), t.elapsed_s()
) # return empty path, number of nodes explored and time elapsed
else: # solution found
return (solution.path(), len(explored.explored_set), t.elapsed_s()
) # return solution path, number of nodes expanded and time
def graph_search(problem, verbose=False, debug=False):
"""graph_search(problem, verbose, debug) - Given a problem representation
(instance of basicsearch_lib02.representation.Problem or derived class),
attempt to solve the problem.
If debug is True, debugging information will be displayed.
if verbose is True, the following information will be displayed:
Number of moves to solution
List of moves and resulting puzzle states
Example:
Solution in 25 moves
Initial state
0 1 2
0 4 8 7
1 5 . 2
2 3 6 1
Move 1 - [0, -1]
0 1 2
0 4 8 7
1 . 5 2
2 3 6 1
Move 2 - [1, 0]
0 1 2
0 4 8 7
1 3 5 2
2 . 6 1
... more moves ...
0 1 2
0 1 3 5
1 4 2 .
2 6 7 8
Move 22 - [-1, 0]
0 1 2
0 1 3 .
1 4 2 5
2 6 7 8
Move 23 - [0, -1]
0 1 2
0 1 . 3
1 4 2 5
2 6 7 8
Move 24 - [1, 0]
0 1 2
0 1 2 3
1 4 . 5
2 6 7 8
If no solution were found (not possible with the puzzles we
are using), we would display:
No solution found
Returns a tuple (path, nodes_explored) where:
path - list of actions to solve the problem or None if no solution was found
nodes_explored - Number of nodes explored (dequeued from frontier)
"""
path = []
nodes_explored = 0
return_tuple = ()
node = Node(problem, problem.initial) # root node
frontier = PriorityQueue(order=min,
f=lambda x: x.get_f()) # todo Sort this out
explored = Explored()
frontier.append(node)
if problem.goal_test(node.state):
path = node.solution()
return_tuple = (path, nodes_explored)
return return_tuple
counter = 0
while True:
if frontier.__len__() == 0:
path = node.solution()
nodes_explored = counter
return_tuple = (path, nodes_explored)
return return_tuple
node = frontier.pop()
if problem.goal_test(node.state):
break
child_nodes = node.expand(problem)
if explored.add(node.state):
counter = counter + 1
for child_node in child_nodes:
if child_node not in frontier and not explored.exists(
child_node.state):
frontier.append(child_node)
path = node.solution()
node_path = node.path()
if verbose:
print("Solution in " + str(len(node_path) - 1) + " moves.")
i = 0
for sol in node_path:
if i is 0:
print("Initial state")
print(sol.state)
i = i + 1
continue
print("Move " + str(i) + " - " + str(path[i - 1]))
print(sol.state)
i = i + 1
nodes_explored = counter
return_tuple = (path, nodes_explored)
return return_tuple