Negamax是否应具有与Negamax Alpha-Beta相同的结果?我有不同的结果

时间:2019-05-04 04:13:51

标签: python artificial-intelligence minimax negamax

我实现了negamax,当尝试实现alpha beta版本时,结果是不同的。据我了解,无论节点顺序如何,它们都应该相同。

我的评估函数返回具有玩家角度的平衡值,如果游戏结束则返回MAX(否则赢得MIN)。我的初始参数是alpha = MIN beta = MAX

def negamax(self, player, board, depth):
    if depth == 0 or board.end_of_game():
        return self.evaluate(player, board), None

    value = self.MIN

    def try_move(move):
        temp_board = deepcopy(board)
        temp_board.make_move(move, player)
        return temp_board

    moves = board.legal_moves(player)

    if not moves:  # Current player has no move
        return self.evaluate(player, board), None

    best_move = moves[0]
    for m in moves:
        value, best_move = max((value, best_move), (-self.negamax(board.opponent(player), try_move(m), depth-1)[0], m))
    return value, best_move

def negamax_AB(self, player, board, depth, alpha, beta):
    if depth == 0 or board.end_of_game():
        return self.evaluate(player, board), None

    value = self.MIN

    def try_move(move):
        temp_board = deepcopy(board)
        temp_board.make_move(move, player)
        return temp_board

    moves = board.legal_moves(player)

    if not moves:  # Current player has no move
        return self.evaluate(player, board), None

    best_move = moves[0]
    for m in moves:
        value, best_move = max((value, best_move), (-self.negamax_AB(board.opponent(player), try_move(m), depth-1, -beta, -alpha)[0], m))
        alpha = max(alpha, value)
        if alpha >= beta:
            break
    return value, best_move

0 个答案:

没有答案