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chess/scripts/simulation.py
Josh 4fc982eac2
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Python tests (make) / test (push) Successful in 11s
Add some basic algorithms and eval functions for an AI
2025-08-23 13:10:05 -04:00

149 lines
3.9 KiB
Python

from binding.python_c_ffi import Board
from binding.python_c_ffi import Move
from binding.python_c_ffi import ChessFFI
from binding.python_c_ffi import WHITE
from binding.python_c_ffi import print_board
from binding.python_c_ffi import sq_to_coord
from scripts.evaluation import RandomEval
from scripts.evaluation import NegaMaxEval
YMD_HM = "%Y-%m-%d-%H-%M"
MAX_MOVES = 256
DATA_PATH = "./data"
class Engine:
def __init__(self, strat_white=None, strat_black=None, max_plys=500):
self.chess_ffi = ChessFFI()
self.board = Board()
self.max_plys = max_plys
self.moves = []
self._load_attack_cache()
self._seed_engine()
random_strat = RandomEval(chess_ffi=self.chess_ffi)
nega_strat = NegaMaxEval(chess_ffi=self.chess_ffi, depth=2, cp_window=30)
if not strat_white:
self.strat_white = random_strat
else:
self.strat_white = strat_white
if not strat_black:
self.strat_black = random_strat
else:
self.strat_black = strat_black
def run(self, fen):
self.chess_ffi.load_fen(self.board, fen)
self._clear_moves()
plys = 0
while plys <= self.max_plys:
print_board(self.board)
moves_buf = (Move * MAX_MOVES)()
n_legal = self.chess_ffi.get_legal_moves(self.board, moves_buf)
game_over, ending = self._is_game_over(n_legal)
if game_over:
print(ending)
break
legal = [moves_buf[i] for i in range(n_legal)]
if self.board.side_to_move == WHITE:
best_move = self.strat_white.get_best_move(self.board, legal)
else:
best_move = self.strat_black.get_best_move(self.board, legal)
new_board = Board()
if not self.chess_ffi.apply_move_on_copy(self.board, new_board, best_move):
print("ERROR: apply_move_on_copy failed")
break
self.board = new_board
plys += 1
move = self.to_uci(best_move)
self.moves.append(move)
if self.board.halfmove_clock >= 100:
print("draw (50-move rule)")
break
for move in self.moves:
# print(move)
pass
print("done")
print(f"winner: {self.side_tag(not self.board.side_to_move)}")
print(len(self.moves))
def side_tag(self, side):
return 'w' if side == WHITE else 'b'
def load_fen(self, fen):
self.chess_ffi.load_fen(self.board, fen)
def _clear_moves(self):
self.moves = []
def to_uci(self, move):
fr = sq_to_coord(getattr(move, "from"))
to = sq_to_coord(move.to)
promo = getattr(move, "promo", 0) or ""
if promo:
MAP = {
1:"n",
2:"b",
3:"r",
4:"q",
"n":"n",
"b":"b",
"r":"r",
"q":"q"
}
promo = MAP.get(promo, "").lower()
return f"{fr}{to}{promo}"
def _load_attack_cache(self):
self.chess_ffi.init_attack_cache()
def _seed_engine(self):
import ctypes as C, time
seed = time.time_ns()
s32 = int(seed) & 0xFFFFFFFF
libc = C.CDLL("libc.so.6") # on Ubuntu
libc.srand.argtypes = (C.c_uint,)
libc.srand.restype = None
libc.srand(C.c_uint(s32))
return s32
def _is_game_over(self, legal_moves):
if legal_moves == 0:
if self.chess_ffi.in_check(self.board, self.board.side_to_move):
ending = "checkmate"
else:
ending = "stalemate"
return True, ending
return False, None
if __name__ == "__main__":
engine = Engine()
fen = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"
engine.run(fen)