From 9a287fe6480f1dec4459c5ce948317292fc93511 Mon Sep 17 00:00:00 2001
From: luk3k <luke.kuess@gmail.com>
Date: Thu, 25 Jan 2024 11:29:29 +0100
Subject: [PATCH] added probabilistic stockfish simulation to engine

---
 engine.py        | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 main.py          | 16 ++++++++++++++++
 requirements.txt |  3 ++-
 3 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/engine.py b/engine.py
index db50503..0051260 100644
--- a/engine.py
+++ b/engine.py
@@ -1,6 +1,9 @@
 import chess
 import chess.engine
 import random
+import eval
+import numpy as np
+from stockfish import Stockfish
 
 
 def pick_move(board: chess.Board) -> chess.Move | None:
@@ -32,3 +35,46 @@ def simulate_game(board: chess.Board, move: chess.Move, depth: int):
         board.push(r.move)
 
     engine.quit()
+
+
+def simulate_stockfish_prob(board: chess.Board, move: chess.Move, games: int = 10, depth: int = 10) -> (float, float):
+    """
+    Simulate a game using
+    :param board: chess board
+    :param move: chosen move
+    :param games: number of games that should be simulated after playing the move
+    :param depth: simulation depth per game
+    :return:
+    """
+    board.push(move)
+    copied_board = board.copy()
+    scores = []
+
+    stockfish = Stockfish("./stockfish/stockfish-ubuntu-x86-64-avx2", depth=2, parameters={"Threads": 8, "Hash": 2048})
+    stockfish.set_elo_rating(1200)
+    stockfish.set_fen_position(board.fen())
+
+    def reset_game():
+        nonlocal scores, copied_board, board
+        score = eval.score_stockfish(copied_board).white().score(mate_score=100_000)
+        scores.append(score)
+        copied_board = board.copy()
+        stockfish.set_fen_position(board.fen())
+
+    for _ in range(games):
+        for d in range(depth):
+            if copied_board.is_game_over() or d == depth - 1:
+                reset_game()
+                break
+
+            if d == depth - 1:
+                reset_game()
+
+            top_moves = stockfish.get_top_moves(3)
+            chosen_move = random.choice(top_moves)['Move']
+            stockfish.make_moves_from_current_position([chosen_move])
+            copied_board.push(chess.Move.from_uci(chosen_move))
+
+    print(scores)
+    # TODO: return distribution here?
+    return np.array(scores).mean(), np.array(scores).std()
diff --git a/main.py b/main.py
index e3b501d..5171f16 100644
--- a/main.py
+++ b/main.py
@@ -29,6 +29,21 @@ def test_stockfish():
     analyze_results(sorted_moves)
 
 
+def test_stockfish_prob():
+    fools_mate = "rnbqkbnr/pppp1ppp/4p3/8/5PP1/8/PPPPP2P/RNBQKBNR b KQkq f3 0 2"
+    board = chess.Board(fools_mate)
+    moves = {}
+    untried_moves = list(board.legal_moves)
+    for move in untried_moves:
+        mean, std = engine.simulate_stockfish_prob(board, move, 10, 4)
+        moves[move] = (mean, std)
+        board = chess.Board(fools_mate)
+
+    sorted_moves = dict(sorted(moves.items(), key=lambda x: x[0].uci()))
+    for m, s in sorted_moves.items():
+        print(f"move '{m.uci()}' (prob_stockfish): mean={s[0]}, std={s[1]}")
+
+
 def analyze_results(moves: dict):
     for m, b in moves.items():
         manual_score = eval.score_manual(b)
@@ -39,6 +54,7 @@ def analyze_results(moves: dict):
 def main():
     test_mcts()
     test_stockfish()
+    test_stockfish_prob()
 
 
 if __name__ == '__main__':
diff --git a/requirements.txt b/requirements.txt
index 68b140b..b83defa 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,2 +1,3 @@
 chess==1.10.0
-numpy==1.26.3
\ No newline at end of file
+numpy==1.26.3
+stockfish==3.28.0
\ No newline at end of file