def _compute_passed_isolated_pawns(
self, board: SearchBoard,
piece_list: PieceList) -> Tuple[int, int, int, int]:
"""
Computes the score for white and black passed and isolated pawns.
:param board: Board to compute on
:param piece_list: Piece list
:return: white passed pawn score, black, white isolated pawn score, black
"""
white_pawns = board.pieces(chess.PAWN, chess.WHITE).mask
black_pawns = board.pieces(chess.PAWN, chess.BLACK).mask
white_passed, black_passed = 0, 0
white_isolated, black_isolated = 0, 0
for sq in piece_list.square_list(chess.PAWN, chess.WHITE):
# Pawn present and it is passed (note that pawn is guaranteed to be here)
if not self._white_passed_pawns_bbs[sq] & black_pawns:
white_passed += self.pawn_passed[sq // 8]
# Pawn present and is isolated
if not self._isolated_pawns_bbs[sq] & white_pawns:
white_isolated += self.pawn_isolated
for sq in piece_list.square_list(chess.PAWN, chess.BLACK):
if not self._black_passed_pawns_bbs[sq] & white_pawns:
black_passed += self.pawn_passed[7 - (sq // 8)]
if not self._isolated_pawns_bbs[sq] & black_pawns:
black_isolated += self.pawn_isolated
return white_passed, black_passed, white_isolated, black_isolated
def _compute_open_files(self, board: SearchBoard,
piece_list: PieceList) -> Tuple[int, int]:
"""
Computes the score for occupying open files (for rooks and queens)
:param board: Board to consider
:param piece_list: Piece list of the board
:return: White open file score, black open file score
"""
white_pawns = board.pieces(chess.PAWN, chess.WHITE).mask
black_pawns = board.pieces(chess.PAWN, chess.BLACK).mask
pawns = white_pawns | black_pawns
open_file = lambda s: not (pawns & self._file_bbs[s % 8])
white_semiopen_file = lambda s: not (white_pawns & self._file_bbs[s % 8
])
black_semiopen_file = lambda s: not (black_pawns & self._file_bbs[s % 8
])
white, black = 0, 0
for sq in piece_list.square_list(chess.ROOK, chess.WHITE):
if open_file(sq):
white += self.rook_open_file
elif white_semiopen_file(sq):
white += self.rook_semiopen_file
for sq in piece_list.square_list(chess.ROOK, chess.BLACK):
if open_file(sq):
black += self.rook_open_file
elif black_semiopen_file(sq):
black += self.rook_semiopen_file
# Queens
for sq in piece_list.square_list(chess.QUEEN, chess.WHITE):
if open_file(sq):
white += self.queen_open_file
elif white_semiopen_file(sq):
white += self.queen_semiopen_file
for sq in piece_list.square_list(chess.QUEEN, chess.BLACK):
if open_file(sq):
black += self.queen_open_file
elif black_semiopen_file(sq):
black += self.queen_semiopen_file
return white, black
