add evaluation class for engines

simulation.py

@@ -0,0 +1,72 @@
+import multiprocessing as mp
+import random
+import chess
+import chess.pgn
+from typing import Tuple, List
+from enum import Enum
+from dataclasses import dataclass
+
+from engine import Engine
+
+
+class Winner(Enum):
+    Engine_A = 0
+    Engine_B = 1
+    Draw = 2
+
+
+@dataclass
+class EvaluationResult:
+    winner: Winner
+    game: chess.pgn.Game
+
+
+def simulate_game(white: Engine, black: Engine) -> chess.pgn.Game:
+    board = chess.Board()
+
+    is_white_playing = True
+    while not board.is_game_over():
+        play_result = white.play(board) if is_white_playing else black.play(board)
+        board.push(play_result.move)
+        is_white_playing = not is_white_playing
+
+    game = chess.pgn.Game.from_board(board)
+    game.headers['White'] = white.get_name()
+    game.headers['Black'] = black.get_name()
+    return game
+
+
+class Evaluation:
+    def __init__(self, engine_a: Engine.__class__, engine_b: Engine.__class__):
+        self.engine_a = engine_a
+        self.engine_b = engine_b
+
+    def run(self, n_games=100) -> List[EvaluationResult]:
+        with mp.Pool(mp.cpu_count()) as pool:
+            args = [(self.engine_a, self.engine_b) for i in range(n_games)]
+            return pool.map(Evaluation._test_simulate, args)
+
+    @staticmethod
+    def _test_simulate(arg: Tuple[Engine.__class__, Engine.__class__]) -> EvaluationResult:
+        engine_a, engine_b = arg
+        flip_engines = bool(random.getrandbits(1))
+        if flip_engines:
+            black, white = engine_a(chess.BLACK), engine_b(chess.WHITE)
+        else:
+            white, black = engine_a(chess.WHITE), engine_b(chess.BLACK)
+
+        game = simulate_game(white, black)
+        winner = game.end().board().outcome().winner
+
+        result = Winner.Draw
+        match (winner, flip_engines):
+            case (chess.WHITE, True):
+                result = Winner.Engine_B
+            case (chess.BLACK, True):
+                result = Winner.Engine_A
+            case (chess.WHITE, False):
+                result = Winner.Engine_A
+            case (chess.BLACK, False):
+                result = Winner.Engine_B
+
+        return EvaluationResult(result, game)