def _value_eval(self, game: ReversiGame, piece: str) -> Union[float, int]:
"""The evaluation function for minimax. For Positional Player, the evaluation function
will evaluate the positional advantage of the pieces on the board.
Preconditions:
- piece in {BLACK, WHITE}
:param game: the current game state for evaluation
:return: value evaluated from the current game state
"""
if game.get_winner() is not None:
if game.get_winner() == piece: # win
return math.inf
elif game.get_winner() == 'Draw': # draw
return 0
else: # lose
return -math.inf
else:
num_black, num_white = game.get_num_pieces(
)[BLACK], game.get_num_pieces()[WHITE]
corner_black, corner_white = check_corners(game)
board_filled = (num_black + num_white) / (game.get_size()**2)
if piece == BLACK:
if board_filled < 0.80: # early to middle game
return 10 * (corner_black - corner_white) + len(
game.get_valid_moves())
else: # end game
return num_black / num_white
else:
if board_filled < 0.80: # early to middle game
return 10 * (corner_white - corner_black) + len(
game.get_valid_moves())
else: # end game
return num_white / num_black
def _value_eval(self, game: ReversiGame, piece: str) -> Union[float, int]:
"""The evaluation function for minimax. For Positional Player, the evaluation function
will evaluate the positional advantage of the pieces on the board.
Preconditions:
- piece in {BLACK, WHITE}
:param game: the current game state for evaluation
:return: value evaluated from the current game state
"""
if game.get_winner() is not None:
if game.get_winner() == piece: # win
return math.inf
elif game.get_winner() == 'Draw': # draw
return 0
else: # lose
return -math.inf
else:
num_black, num_white = game.get_num_pieces(
)[BLACK], game.get_num_pieces()[WHITE]
board_filled = (num_black + num_white) / (game.get_size()**2)
if game.get_size() == 8:
selected_board_weight = BOARD_WEIGHT_8
else:
selected_board_weight = BOARD_WEIGHT_6
if board_filled < 0.80:
return positional_early(game, selected_board_weight, piece)
else:
if piece == BLACK:
return num_black / num_white
if piece == WHITE:
return num_white / num_black
return 0
def _value_eval(self, game: ReversiGame, piece: str) -> Union[float, int]:
"""The evaluation function for minimax. The evaluation function will
return the number of piece of its side
Preconditions:
- piece in {BLACK, WHITE}
:param game: the current game state for evaluation
:return: the evaluated value of the current state
"""
if game.get_winner() is not None:
if game.get_winner() == piece: # win
return math.inf
elif game.get_winner() == 'Draw': # draw
return 0
else: # lose
return -math.inf
else:
if piece == BLACK:
return game.get_num_pieces()[BLACK] / game.get_num_pieces(
)[WHITE]
else:
return game.get_num_pieces()[WHITE] / game.get_num_pieces(
)[BLACK]