def boardToPieceFeatures(board, player = chess.WHITE):
boardState = np.zeros((0, 8, 8))
# Pawn = 1, King = 6
for currPiece in range(1,7):
pieceBits = np.array(SquareSet(board.pieces(currPiece, player)).tolist(), dtype = np.uint8).reshape(8, 8)
pieceBits = np.flip(pieceBits)
# If the current player is black, then rotate the board 180 degrees.
if player == chess.BLACK:
pieceBits = np.rot90(pieceBits, k=2)
boardState = np.append(boardState, [pieceBits], axis = 0)
for currPiece in range(1,7):
pieceBits = np.array(SquareSet(board.pieces(currPiece, not player)).tolist(), dtype = np.uint8).reshape(8, 8)
pieceBits = np.flip(pieceBits)
# If the current player is black, then rotate the board 180 degrees.
if player == chess.BLACK:
pieceBits = np.rot90(pieceBits, k=2)
boardState = np.append(boardState, [pieceBits], axis = 0)
# Returns a 12 x 8 x 8 array of the current board state.
return boardState
def develops(self, move):
if self.board.san(move) == 'O-O' or self.board.san(move) == 'O-O-O':
return True
to_move = self.board.turn
piece_type = self.board.piece_type_at(move.from_square)
if piece_type == chess.ROOK:
return True
elif piece_type == chess.PAWN or piece_type == chess.KING:
return False
if to_move == chess.WHITE:
return move.from_square in SquareSet(chess.BB_RANK_1)
elif to_move == chess.BLACK:
return move.from_square in SquareSet(chess.BB_RANK_8)
return False
def back_rank_mate(puzzle: Puzzle) -> bool:
node = puzzle.game.end()
board = node.board()
king = board.king(not puzzle.pov)
assert king is not None
assert isinstance(node, ChildNode)
back_rank = 7 if puzzle.pov else 0
if board.is_checkmate() and square_rank(king) == back_rank:
squares = SquareSet.from_square(king + (-8 if puzzle.pov else 8))
if puzzle.pov:
if chess.square_file(king) < 7:
squares.add(king - 7)
if chess.square_file(king) > 0:
squares.add(king - 9)
else:
if chess.square_file(king) < 7:
squares.add(king + 9)
if chess.square_file(king) > 0:
squares.add(king + 7)
for square in squares:
piece = board.piece_at(square)
if piece is None or piece.color == puzzle.pov or board.attackers(
puzzle.pov, square):
return False
return any(
square_rank(checker) == back_rank for checker in board.checkers())
return False
def _generate_svg(x, y, previous_positions):
"""
Generate a single svg for one frame of the animation
Parameters
----------
x: int
the current x position of the knight starting from the top left (zero-indexed)
y: int
the current y position of the knight starting from the top left (zero-indexed)
previous_positions: list
a list of previous positions of the knight, which will be marked with an 'x' symbol in the animation
Returns
-------
str
the SVG of the current position of the knight with previous steps shown
"""
# represent the knight on the board
board = Board(_convert_coord_to_fen(x, y))
# represent the previous positions of the knight
squares = SquareSet(
[square(prev_x, 7 - prev_y) for prev_x, prev_y in previous_positions])
# generate SVG
return svg_board(board=board, squares=squares)
def exposed_king(puzzle: Puzzle) -> bool:
if puzzle.pov:
pov = puzzle.pov
board = puzzle.mainline[0].board()
else:
pov = not puzzle.pov
board = puzzle.mainline[0].board().mirror()
king = board.king(not pov)
assert king is not None
if chess.square_rank(king) < 5:
return False
squares = SquareSet.from_square(king - 8)
if chess.square_file(king) > 0:
squares.add(king - 1)
squares.add(king - 9)
if chess.square_file(king) < 7:
squares.add(king + 1)
squares.add(king - 7)
for square in squares:
if board.piece_at(square) == Piece(PAWN, not pov):
return False
for node in puzzle.mainline[1::2][1:-1]:
if node.board().is_check():
return True
return False
def dovetail_mate(puzzle: Puzzle) -> bool:
node = puzzle.game.end()
board = node.board()
king = board.king(not puzzle.pov)
assert king is not None
assert isinstance(node, ChildNode)
if square_file(king) in [0, 7] or square_rank(king) in [0, 7]:
return False
queen_square = node.move.to_square
if (util.moved_piece_type(node) != QUEEN
or square_file(queen_square) == square_file(king)
or square_rank(queen_square) == square_rank(king)
or square_distance(queen_square, king) > 1):
return False
for square in [
s for s in SquareSet(chess.BB_ALL) if square_distance(s, king) == 1
]:
if square == queen_square:
continue
attackers = list(board.attackers(puzzle.pov, square))
if attackers == [queen_square]:
if board.piece_at(square):
return False
elif attackers:
return False
return True
def get_attacked_defended(self):
attacked = np.full(64, 0.0)
defended = np.full(64, 0.0)
our = self.occupied_co[self.turn]
their = self.occupied_co[not self.turn]
for square in SquareSet(our):
for our_defended in SquareSet(self.attacks_mask(square)):
defended[our_defended] = 1.0
for square in SquareSet(their):
for our_attacked in SquareSet(self.attacks_mask(square)):
attacked[our_attacked] = 1.0
return attacked, defended
def clearance(puzzle: Puzzle) -> bool:
for node in puzzle.mainline[1::2][1:]:
board = node.board()
if not node.parent.board().piece_at(node.move.to_square):
piece = board.piece_at(node.move.to_square)
if piece and piece.piece_type in util.ray_piece_types:
prev = node.parent.parent
assert prev
prev_move = prev.move
assert prev_move
assert isinstance(node.parent, ChildNode)
if (not prev_move.promotion
and prev_move.to_square != node.move.from_square
and prev_move.to_square != node.move.to_square
and not node.parent.board().is_check()
and (not board.is_check()
or util.moved_piece_type(node.parent) != KING)):
if (prev_move.from_square == node.move.to_square
or prev_move.from_square in SquareSet.between(
node.move.from_square, node.move.to_square)):
if prev.parent and not prev.parent.board().piece_at(
prev_move.to_square) or util.is_in_bad_spot(
prev.board(), prev_move.to_square):
return True
return False
def dims_knight(self, move):
'''Knight on the rim is dim'''
if self.board.piece_type_at(move.from_square) == chess.KNIGHT:
rim = SquareSet(
chess.BB_RANK_1 | \
chess.BB_RANK_8 | \
chess.BB_FILE_A | \
chess.BB_FILE_H)
return move.to_square in rim
def opens_position(self, move):
to_move = self.board.turn
if self.board.piece_type_at(move.from_square) == chess.PAWN:
if move.to_square not in SquareSet(chess.BB_RANK_1 | chess.BB_RANK_8):
num_pawns_before = len(self.board.pieces(chess.PAWN, not to_move))
analysis_board = chess.Board(self.board.fen())
analysis_board.push(move)
num_pawns_after = len(analysis_board.pieces(chess.PAWN, not to_move))
return num_pawns_before != num_pawns_after
return False
def controls(self, move):
'''Returns a set of attacked/defended squares'''
to_move = self.board.turn
analysis_board = chess.Board(self.board.fen())
analysis_board.push(move)
squares = 0
for square in chess.SQUARES:
if move.to_square in analysis_board.attackers(to_move, square):
squares |= chess.BB_SQUARES[square]
return SquareSet(squares)
def discovered_attack(puzzle: Puzzle) -> bool:
if discovered_check(puzzle):
return True
for node in puzzle.mainline[1::2][1:]:
if util.is_capture(node):
between = SquareSet.between(node.move.from_square,
node.move.to_square)
if node.parent.move.to_square == node.move.to_square:
return False
prev = node.parent.parent
if prev.move.from_square in between and node.move.to_square != prev.move.to_square:
return True
return False
def self_interference(puzzle: Puzzle) -> bool:
# intereference by opponent piece
for node in puzzle.mainline[1::2][1:]:
prev_board = node.parent.board()
square = node.move.to_square
capture = prev_board.piece_at(square)
if capture and util.is_hanging(prev_board, capture, square):
init_board = node.parent.parent.board()
defenders = init_board.attackers(capture.color, square)
defender = defenders.pop() if defenders else None
if defender and init_board.piece_at(
defender).piece_type in util.ray_piece_types:
if node.parent.move.to_square in SquareSet.between(
square, defender):
return True
return False
def skewer(puzzle: Puzzle) -> bool:
for node in puzzle.mainline[1::2][1:]:
prev = node.parent
assert isinstance(prev, ChildNode)
capture = prev.board().piece_at(node.move.to_square)
if capture and util.moved_piece_type(node) in util.ray_piece_types and not node.board().is_checkmate():
between = SquareSet.between(node.move.from_square, node.move.to_square)
op_move = prev.move
assert op_move
if op_move.to_square == node.move.to_square or not op_move.from_square in between:
continue
if util.king_values[util.moved_piece_type(prev)] > util.king_values[capture.piece_type] and util.is_in_bad_spot(
prev.board(), node.move.to_square
):
return True
return False
def x_ray(puzzle: Puzzle) -> bool:
for node in puzzle.mainline[1::2][1:]:
if not util.is_capture(node):
continue
prev_op_node = node.parent
assert isinstance(prev_op_node, ChildNode)
if prev_op_node.move.to_square != node.move.to_square or util.moved_piece_type(prev_op_node) == KING:
continue
prev_pl_node = prev_op_node.parent
assert isinstance(prev_pl_node, ChildNode)
if prev_pl_node.move.to_square != prev_op_node.move.to_square:
continue
if prev_op_node.move.from_square in SquareSet.between(node.move.from_square, node.move.to_square):
return True
return False
def boden_or_double_bishop_mate(puzzle: Puzzle):
node = puzzle.game.end()
board = node.board()
king = board.king(not puzzle.pov)
assert king is not None
assert isinstance(node, ChildNode)
bishop_squares = list(board.pieces(BISHOP, puzzle.pov))
if len(bishop_squares) < 2:
return None
for square in [s for s in SquareSet(chess.BB_ALL) if square_distance(s, king) < 2]:
if not all([p.piece_type == BISHOP for p in util.attacker_pieces(board, puzzle.pov, square)]):
return None
if (square_file(bishop_squares[0]) < square_file(king)) == (square_file(bishop_squares[1]) > square_file(king)):
return "bodenMate"
else:
return "doubleBishopMate"
def discovered_attack(puzzle: Puzzle) -> bool:
if discovered_check(puzzle):
return True
for node in puzzle.mainline[1::2][1:]:
if util.is_capture(node):
between = SquareSet.between(node.move.from_square,
node.move.to_square)
assert isinstance(node.parent, ChildNode)
if node.parent.move.to_square == node.move.to_square:
return False
prev = node.parent.parent
assert isinstance(prev, ChildNode)
if (prev.move.from_square in between
and node.move.to_square != prev.move.to_square
and node.move.from_square != prev.move.to_square
and not util.is_castling(prev)):
return True
return False
def skewer(puzzle: Puzzle) -> bool:
def value(pt: PieceType):
return 10 if pt == KING else util.values[pt]
for node in puzzle.mainline[1::2][1:]:
prev = node.parent
capture = prev.board().piece_at(node.move.to_square)
if capture and util.moved_piece_type(
node
) in util.ray_piece_types and not node.board().is_checkmate():
between = SquareSet.between(node.move.from_square,
node.move.to_square)
op_move = prev.move
if (op_move.to_square == node.move.to_square
or not op_move.from_square in between):
continue
if value(util.moved_piece_type(prev)) > value(capture.piece_type):
return True
return False
def closes_position(self, move):
piece = self.board.piece_at(move.from_square)
if piece and piece.piece_type == chess.PAWN:
if not self.opens_position(move):
from_bb_square = chess.BB_SQUARES[move.from_square]
pawn_attack = 0
if piece.color == chess.WHITE:
pawn_attack |= chess.shift_up_left(from_bb_square)
pawn_attack |= chess.shift_up_right(from_bb_square)
elif piece.color == chess.BLACK:
pawn_attack |= chess.shift_down_left(from_bb_square)
pawn_attack |= chess.shift_down_right(from_bb_square)
for square in SquareSet(pawn_attack):
passed_up_piece = self.board.piece_at(square)
if passed_up_piece:
if passed_up_piece.color != self.board.turn and \
passed_up_piece.piece_type == chess.PAWN:
return True
return False
def interference(puzzle: Puzzle) -> bool:
# intereference by player piece
for node in puzzle.mainline[1::2][1:]:
prev_board = node.parent.board()
square = node.move.to_square
capture = prev_board.piece_at(square)
assert node.parent.move
if capture and square != node.parent.move.to_square and util.is_hanging(prev_board, capture, square):
assert node.parent
assert node.parent.parent
assert node.parent.parent.parent
init_board = node.parent.parent.parent.board()
defenders = init_board.attackers(capture.color, square)
defender = defenders.pop() if defenders else None
defender_piece = init_board.piece_at(defender) if defender else None
if defender and defender_piece and defender_piece.piece_type in util.ray_piece_types:
interfering = node.parent.parent
if interfering.move and interfering.move.to_square in SquareSet.between(square, defender):
return True
return False
def bit_set_count(square_set: chess.SquareSet):
result = 0
while square_set:
square_set.pop()
result += 1
return result
def controls_center(self, move):
center = SquareSet(chess.BB_D4 | chess.BB_D5 | chess.BB_E4 | chess.BB_E5)
for square in self.controls(move):
if square in center:
return True
return False