def find_puzzle_candidates(game: Game, scan_depth=SCAN_DEPTH) -> List[Puzzle]:
""" finds puzzle candidates from a chess game
"""
log(Color.DIM, "Scanning game for puzzles (depth: %d)..." % scan_depth)
prev_score = Cp(0)
puzzles = []
i = 0
node = game
while not node.is_end():
next_node = node.variation(0)
next_board = next_node.board()
cur_score = AnalysisEngine.best_move(next_board, scan_depth).score
board = node.board()
highlight_move = False
if should_investigate(prev_score, cur_score, board):
highlight_move = True
puzzle = Puzzle(
board,
next_node.move,
)
puzzles.append(puzzle)
log_move(board, next_node.move, cur_score, highlight=highlight_move)
prev_score = cur_score
node = next_node
i += 1
return puzzles
def _analyze(board, depth, **kwargs) -> Union[List[InfoDict], InfoDict]:
try:
info = AnalysisEngine.instance().analyse(board, Limit(depth=depth), **kwargs)
except EngineTerminatedError:
log(Color.RED, "Analysis engine crashed... restarting")
AnalysisEngine.quit()
info = AnalysisEngine._analyze(board, depth, **kwargs)
return info
def _calculate_candidate_moves(self, depth):
""" Find the best move from board position using multipv 3
"""
multipv = NUM_CANDIDATE_MOVES
log(Color.BLACK, "Evaluating best %d moves (depth %d)..." % (multipv, depth))
self.candidate_moves = AnalysisEngine.best_moves(self.board, depth, multipv)
for analyzed_move in self.candidate_moves:
self._log_move(analyzed_move.move, analyzed_move.score)
def _calculate_best_move(self, depth):
""" Find the best move from board position using multipv 1
"""
log(Color.BLACK, "Evaluating best move (depth %d)..." % depth)
best_move = AnalysisEngine.best_move(self.board, depth)
self.best_move = best_move.move
self.score = best_move.score
if self._num_legal_moves() == 1:
self.candidate_moves = [best_move]
self._log_move(self.best_move, self.score)
def _analyze_best_initial_move(self, depth) -> Move:
log(Color.BLACK, "Evaluating best initial move (depth %d)..." % depth)
best_move = AnalysisEngine.best_move(self.initial_board, depth)
if best_move.move:
self.analyzed_moves.append(best_move)
log_move(self.initial_board,
best_move.move,
best_move.score,
show_uci=True)
self.initial_score = best_move.score
return best_move.move
def _analyze_initial_moves(self, depth):
""" get the score of the position before the initial move
also get the score of the position after the initial move
"""
best_move = self._analyze_best_initial_move(depth)
if not self.initial_move:
return
elif self.initial_move == best_move:
log(Color.BLACK, "The move played was the best move")
else:
log(Color.BLACK,
"Evaluating played initial move (depth %d)..." % depth)
analyzed_move = AnalysisEngine.evaluate_move(
self.initial_board, self.initial_move, depth)
self.analyzed_moves.append(analyzed_move)
log_move(self.initial_board,
self.initial_move,
analyzed_move.score,
show_uci=True)
def _log_position(self):
if self.initial_move:
move_san = self.initial_board.san(self.initial_move)
log(
Color.VIOLET, "\nAfter %s %s" %
(fullmove_string(self.initial_board).strip(), move_san))
log_board(self.board)
log(Color.DARK_BLUE,
"Material difference: %d" % material_difference(self.board))
log(Color.DARK_BLUE,
"# legal moves: %d" % self._num_legal_moves())
def generate(self, depth):
""" Generate new positions for the puzzle until a final position is reached
"""
log_board(self.initial_board)
self._analyze_initial_moves(depth)
self._set_initial_position()
position = self.initial_position
position.evaluate(depth)
self.player_moves_first = self._player_moves_first()
is_player_move = not self.player_moves_first
while True:
self.positions.append(position)
if position.is_final(is_player_move):
log_str = "Not going deeper: "
if position.is_ambiguous():
log_str += "ambiguous"
elif position.board.is_game_over():
log_str += "game over"
log(Color.YELLOW, log_str)
break
else:
log_str = "Going deeper..."
if is_player_move is not None:
if is_player_move:
if len(position.candidate_moves) == 1:
log_str += " only one move"
else:
log_str += " one clear best move"
else:
log_str += " not player move"
log(Color.DIM, log_str)
position = PuzzlePosition(position.board, position.best_move)
position.evaluate(depth)
is_player_move = not is_player_move
self._calculate_final_score(depth)
if self.is_complete():
log(Color.GREEN, "Puzzle is complete")
else:
log(Color.RED, "Puzzle incomplete")
def print_puzzle_pgn(puzzle, pgn_headers=None):
puzzle_pgn = puzzle.to_pgn(pgn_headers=pgn_headers)
log(Color.MAGENTA, "NEW PUZZLE GENERATED\n")
print(Color.CYAN + puzzle_pgn + "\n\n" + Color.ENDC)
if settings.quiet:
configure_logging(level=logging.INFO)
else:
configure_logging(level=logging.DEBUG)
def print_puzzle_pgn(puzzle, pgn_headers=None):
puzzle_pgn = puzzle.to_pgn(pgn_headers=pgn_headers)
log(Color.MAGENTA, "NEW PUZZLE GENERATED\n")
print(Color.CYAN + puzzle_pgn + "\n\n" + Color.ENDC)
# load a FEN and try to create a puzzle from it
if settings.fen:
log(Color.DIM, AnalysisEngine.name())
puzzle = Puzzle(Board(settings.fen))
puzzle.generate(depth=settings.search_depth)
if puzzle.is_complete():
print_puzzle_pgn(puzzle)
engine.quit()
exit(0)
# load games from a PGN and scan them for puzzles
n_positions = 0 # number of positions considered
n_puzzles = 0 # number of puzzles generated
game_id = 0
pgn = open(settings.pgn, "r")
while game_id < settings.start_index: