pyhton实现UCT算法的人机交互五子棋
时间: 2023-05-12 08:06:10 浏览: 84
可以使用Python实现UCT算法来实现人机交互五子棋。UCT算法是一种基于蒙特卡罗树搜索的算法,可以在不完全信息的情况下进行决策。在五子棋中,可以使用UCT算法来选择最优的下棋位置。具体实现可以参考相关的Python库和代码示例。
相关问题
用python实现UCT算法
好的,下面是一个简单的Python实现UCT算法的示例代码:
```python
import math
import random
class Node:
def __init__(self, state, parent=None):
self.state = state
self.parent = parent
self.children = []
self.wins = 0
self.visits = 0
def is_leaf(self):
return len(self.children) == 0
def is_fully_expanded(self):
return all(child.visits > 0 for child in self.children)
def add_child(self, child_state):
child_node = Node(child_state, self)
self.children.append(child_node)
return child_node
class UCT:
def __init__(self, state, exploration_constant=1.4):
self.root = Node(state)
self.exploration_constant = exploration_constant
def select(self):
node = self.root
while not node.is_leaf():
node = self._uct_select(node)
return node
def expand(self, node):
untried_actions = [action for action in self._get_actions(node.state) if not any(child.state == action for child in node.children)]
if untried_actions:
action = random.choice(untried_actions)
child_node = node.add_child(action)
return child_node
else:
return None
def simulate(self, state):
while not self._is_terminal(state):
action = random.choice(self._get_actions(state))
state = self._get_next_state(state, action)
return self._get_reward(state)
def backpropagate(self, node, reward):
while node is not None:
node.visits += 1
node.wins += reward
node = node.parent
def run(self, num_iterations):
for i in range(num_iterations):
node = self.select()
child = self.expand(node)
if child:
reward = self.simulate(child.state)
self.backpropagate(child, reward)
else:
reward = self.simulate(node.state)
self.backpropagate(node, reward)
best_child = None
best_score = float('-inf')
for child in self.root.children:
score = child.wins / child.visits + self.exploration_constant * math.sqrt(2 * math.log(self.root.visits) / child.visits)
if score > best_score:
best_child = child
best_score = score
return best_child.state
def _uct_select(self, node):
best_child = None
best_score = float('-inf')
for child in node.children:
score = child.wins / child.visits + self.exploration_constant * math.sqrt(2 * math.log(node.visits) / child.visits)
if score > best_score:
best_child = child
best_score = score
return best_child
def _get_actions(self, state):
# Return a list of possible actions from the given state
pass
def _get_next_state(self, state, action):
# Return the next state given the current state and action
pass
def _get_reward(self, state):
# Return the reward for the given state
pass
def _is_terminal(self, state):
# Return True if the given state is a terminal state, False otherwise
pass
```
要使用这个算法,需要在 `UCT` 类中实现 `_get_actions`、`_get_next_state`、`_get_reward` 和 `_is_terminal` 方法。这些方法需要根据具体的问题实现。
例如,如果我们想使用 UCT 算法解决一个棋盘游戏,可以实现这些方法如下:
```python
class Board:
def __init__(self):
self.board = [[0] * 3 for _ in range(3)]
def is_valid_move(self, row, col):
return self.board[row][col] == 0
def make_move(self, row, col, player):
self.board[row][col] = player
def is_win(self, player):
for i in range(3):
if self.board[i][0] == player and self.board[i][1] == player and self.board[i][2] == player:
return True
if self.board[0][i] == player and self.board[1][i] == player and self.board[2][i] == player:
return True
if self.board[0][0] == player and self.board[1][1] == player and self.board[2][2] == player:
return True
if self.board[0][2] == player and self.board[1][1] == player and self.board[2][0] == player:
return True
return False
def is_full(self):
return all(self.board[i][j] != 0 for i in range(3) for j in range(3))
class TicTacToeUCT(UCT):
def __init__(self):
super().__init__(Board())
def _get_actions(self, state):
actions = []
for i in range(3):
for j in range(3):
if state.is_valid_move(i, j):
actions.append((i, j))
return actions
def _get_next_state(self, state, action):
row, col = action
player = 1 if state.is_full() or state.is_win(2) else 2
next_state = Board()
next_state.board = [row[:] for row in state.board]
next_state.make_move(row, col, player)
return next_state
def _get_reward(self, state):
if state.is_win(1):
return 1
elif state.is_win(2):
return 0
else:
return 0.5
def _is_terminal(self, state):
return state.is_full() or state.is_win(1) or state.is_win(2)
```
这个例子中,我们使用 UCT 算法解决井字棋游戏。对于 `_get_actions` 方法,我们返回一个包含所有空位置的列表。对于 `_get_next_state` 方法,我们先判断当前玩家是谁,然后创建一个新的棋盘状态,并在新状态上执行该动作。对于 `_get_reward` 方法,我们返回 1(玩家1赢)、0(玩家2赢)或0.5(平局)中的一个。对于 `_is_terminal` 方法,我们检查棋盘是否已满或某个玩家已经赢了。
使用这个算法的示例代码如下:
```python
game = TicTacToeUCT()
for i in range(10000):
game.run(1)
best_move = game.run(100)
print(best_move)
```
这个例子中,我们在 UCT 算法中运行 10000 次迭代,然后再运行 100 次迭代来选择下一步最佳动作。在这个例子中,UCT 算法将选择最有可能导致胜利的行动。
python用uct算法实现井字棋
可以使用以下代码实现:
```
import random
class Node:
def __init__(self, state, parent=None):
self.state = state
self.parent = parent
self.children = []
self.wins = 0
self.visits = 0
def add_child(self, child_state):
child = Node(child_state, self)
self.children.append(child)
return child
def update(self, result):
self.visits += 1
self.wins += result
def fully_expanded(self):
return len(self.children) == len(self.state.get_legal_moves())
def best_child(self, c_param=1.4):
choices_weights = [
(c.wins / c.visits) + c_param * math.sqrt((2 * math.log(self.visits) / c.visits))
for c in self.children
]
return self.children[choices_weights.index(max(choices_weights))]
def rollout(self):
current_rollout_state = self.state
while not current_rollout_state.is_terminal():
possible_moves = current_rollout_state.get_legal_moves()
if not possible_moves:
break
move = random.choice(possible_moves)
current_rollout_state = current_rollout_state.move(move)
return current_rollout_state.game_result()
def backpropagate(self, result):
node = self
while node is not None:
node.update(result)
node = node.parent
class UCT:
def __init__(self, time_limit=None, iteration_limit=None):
if time_limit:
self.time_limit = time_limit
self.limit_type = 'time'
elif iteration_limit:
self.iteration_limit = iteration_limit
self.limit_type = 'iterations'
else:
raise ValueError("Must supply either time_limit or iteration_limit")
self.states = []
def uct_search(self, state):
self.states = []
root_node = Node(state)
self.states.append(root_node.state)
if self.limit_type == 'time':
time_limit = time.time() + self.time_limit
while time.time() < time_limit:
self.uct_iteration(root_node)
else:
for i in range(self.iteration_limit):
self.uct_iteration(root_node)
best_child = root_node.best_child(c_param=0)
return best_child.state.last_move
def uct_iteration(self, root_node):
node = root_node
state = root_node.state.clone()
# Select
while node.fully_expanded() and not state.is_terminal():
node = node.best_child()
state = state.move(node.state.last_move)
self.states.append(state)
# Expand
if not state.is_terminal():
unexplored_move = random.choice(state.get_legal_moves())
state = state.move(unexplored_move)
self.states.append(state)
node = node.add_child(state)
# Simulate
result = node.rollout()
# Backpropagate
node.backpropagate(result)
```
这是一个基于 UCT 算法的井字棋 AI,可以在 Python 中使用。