Move files into chesspp module

chesspp/eval.py

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+import chess
+import chess.engine
+import sys
+
+# Eval constants for scoring chess boards
+# Evaluation metric inspired by Tomasz Michniewski: https://www.chessprogramming.org/Simplified_Evaluation_Function
+
+PIECE_VALUES = {
+    chess.PAWN: 100,
+    chess.KNIGHT: 320,
+    chess.BISHOP: 330,
+    chess.ROOK: 500,
+    chess.QUEEN: 900,
+    chess.KING: 20000
+}
+
+pawn_eval = [
+    0, 0, 0, 0, 0, 0, 0, 0,
+    5, 10, 10, -20, -20, 10, 10, 5,
+    5, -5, -10, 0, 0, -10, -5, 5,
+    0, 0, 0, 20, 20, 0, 0, 0,
+    5, 5, 10, 25, 25, 10, 5, 5,
+    10, 10, 20, 30, 30, 20, 10, 10,
+    50, 50, 50, 50, 50, 50, 50, 50,
+    0, 0, 0, 0, 0, 0, 0, 0
+]
+knight_eval = [
+    -50, -40, -30, -30, -30, -30, -40, -50,
+    -40, -20, 0, 0, 0, 0, -20, -40,
+    -30, 0, 10, 15, 15, 10, 0, -30,
+    -30, 5, 15, 20, 20, 15, 5, -30,
+    -30, 0, 15, 20, 20, 15, 0, -30,
+    -30, 5, 10, 15, 15, 10, 5, -30,
+    -40, -20, 0, 5, 5, 0, -20, -40,
+    -50, -40, -30, -30, -30, -30, -40, -50
+]
+bishop_eval = [
+    -20, -10, -10, -10, -10, -10, -10, -20,
+    -10, 5, 0, 0, 0, 0, 5, -10,
+    -10, 10, 10, 10, 10, 10, 10, -10,
+    -10, 0, 10, 10, 10, 10, 0, -10,
+    -10, 5, 5, 10, 10, 5, 5, -10,
+    -10, 0, 5, 10, 10, 5, 0, -10,
+    -10, 0, 0, 0, 0, 0, 0, -10,
+    -20, -10, -10, -10, -10, -10, -10, -20
+]
+rook_eval = [
+    0, 0, 0, 5, 5, 0, 0, 0,
+    -5, 0, 0, 0, 0, 0, 0, -5,
+    -5, 0, 0, 0, 0, 0, 0, -5,
+    -5, 0, 0, 0, 0, 0, 0, -5,
+    -5, 0, 0, 0, 0, 0, 0, -5,
+    -5, 0, 0, 0, 0, 0, 0, -5,
+    5, 10, 10, 10, 10, 10, 10, 5,
+    0, 0, 0, 0, 0, 0, 0, 0
+]
+queen_eval = [
+    -20, -10, -10, -5, -5, -10, -10, -20,
+    -10, 0, 0, 0, 0, 0, 0, -10,
+    -10, 0, 5, 5, 5, 5, 0, -10,
+    -5, 0, 5, 5, 5, 5, 0, -5,
+    0, 0, 5, 5, 5, 5, 0, -5,
+    -10, 5, 5, 5, 5, 5, 0, -10,
+    -10, 0, 5, 0, 0, 0, 0, -10,
+    -20, -10, -10, -5, -5, -10, -10, -20
+]
+king_eval = [
+    20, 30, 10, 0, 0, 10, 30, 20,
+    20, 20, 0, 0, 0, 0, 20, 20,
+    -10, -20, -20, -20, -20, -20, -20, -10,
+    20, -30, -30, -40, -40, -30, -30, -20,
+    -30, -40, -40, -50, -50, -40, -40, -30,
+    -30, -40, -40, -50, -50, -40, -40, -30,
+    -30, -40, -40, -50, -50, -40, -40, -30,
+    -30, -40, -40, -50, -50, -40, -40, -30
+]
+king_endgame_eval = [
+    50, -30, -30, -30, -30, -30, -30, -50,
+    -30, -30,  0,  0,  0,  0, -30, -30,
+    -30, -10, 20, 30, 30, 20, -10, -30,
+    -30, -10, 30, 40, 40, 30, -10, -30,
+    -30, -10, 30, 40, 40, 30, -10, -30,
+    -30, -10, 20, 30, 30, 20, -10, -30,
+    -30, -20, -10,  0,  0, -10, -20, -30,
+    -50, -40, -30, -20, -20, -30, -40, -50
+]
+
+PIECE_TABLES = {
+    chess.WHITE: {
+        chess.PAWN: pawn_eval,
+        chess.KNIGHT: knight_eval,
+        chess.BISHOP: bishop_eval,
+        chess.ROOK: rook_eval,
+        chess.QUEEN: queen_eval,
+        chess.KING: king_eval,
+        'end_game_king': king_endgame_eval
+    },
+    chess.BLACK: {
+        chess.PAWN: list(reversed(pawn_eval)),
+        chess.KNIGHT: list(reversed(knight_eval)),
+        chess.BISHOP: list(reversed(bishop_eval)),
+        chess.ROOK: list(reversed(rook_eval)),
+        chess.QUEEN: list(reversed(queen_eval)),
+        chess.KING: list(reversed(king_eval)),
+        'end_game_king': list(reversed(king_endgame_eval))
+    }
+}
+
+
+def check_endgame(board: chess.Board) -> bool:
+    """
+    Endgame according to Tomasz Michniewski:
+        1. Both sides have no queens or
+        2. Every side which has a queen has additionally no other pieces or one minorpiece maximum.
+    """
+    queens_white = 0
+    minors_white = 0
+    queens_black = 0
+    minors_black = 0
+    for s in chess.SQUARES:
+        piece = board.piece_at(s)
+        if piece is None:
+            continue
+
+        if piece.piece_type == chess.QUEEN:
+            if piece.color == chess.WHITE:
+                queens_white += 1 
+            else:
+                queens_black += 1
+
+        if piece.piece_type == chess.BISHOP or piece.piece_type == chess.KNIGHT:
+            if piece.color == chess.WHITE:
+                minors_white += 1 
+            else:
+                minors_black += 1
+
+    return (queens_black == 0 and queens_white == 0) or ((queens_black >= 1 >= minors_black) or (
+                queens_white >= 1 >= minors_white))
+
+
+def score_manual(board: chess.Board) -> int:
+    """
+    Calculate the score of the given board regarding the given color
+    :param board: the chess board
+    :return: score metric
+    """
+    outcome = board.outcome()
+    if outcome is not None:
+        if outcome.termination == chess.Termination.CHECKMATE:
+            return sys.maxsize if outcome.winner == chess.WHITE else -sys.maxsize
+        else:  # draw
+            return 0
+
+    score = 0
+    for s in chess.SQUARES:
+        piece = board.piece_at(s)
+        if piece is None:
+            continue
+
+        if piece.color == chess.WHITE:
+            if piece.piece_type == chess.KING and check_endgame(board):
+                score += PIECE_VALUES[piece.piece_type] * PIECE_TABLES[chess.WHITE]['end_game_king'][s]
+            else:
+                score += PIECE_VALUES[piece.piece_type] * PIECE_TABLES[chess.WHITE][piece.piece_type][s]
+        else:
+            if piece.piece_type == chess.KING and check_endgame(board):
+                score -= PIECE_VALUES[piece.piece_type] * PIECE_TABLES[chess.BLACK]['end_game_king'][s]
+            else:
+                score -= PIECE_VALUES[piece.piece_type] * PIECE_TABLES[chess.BLACK][piece.piece_type][s]
+
+    return score
+
+
+def score_stockfish(board: chess.Board) -> chess.engine.PovScore:
+    """
+    Calculate the score of the given board using stockfish
+    :param board:
+    :return:
+    """
+    engine = chess.engine.SimpleEngine.popen_uci("./stockfish/stockfish-ubuntu-x86-64-avx2")
+    info = engine.analyse(board, chess.engine.Limit(depth=0))
+    engine.quit()
+    return info["score"]