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main.py
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main.py
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import random
import chess
import chess.pgn
import chess.polyglot
from headers import *
from parameters import *
from piece_square_tables import *
from piece_values import *
PAWN, KNIGHT, BISHOP, ROOK, QUEEN, KING = range(1, 7)
WHITE, BLACK = 0, 1
zobrist_keys = {
piece: {color: {square: random.getrandbits(64) for square in range(64)} for color in range(2)}
for piece in range(1, 7)
}
initial_zobrist_key = random.getrandbits(64)
current_key = random.getrandbits(64)
def update_zobrist_key(move, current_key):
from_square, to_square = move.from_square, move.to_square
from_piece = board.piece_at(from_square)
if from_piece is not None:
piece = from_piece.piece_type
color = from_piece.color
new_key = current_key ^ zobrist_keys[piece][color][from_square] ^ zobrist_keys[piece][color][to_square]
else:
new_key = current_key # No piece on the from_square
return new_key
def capture_heuristic(move):
capture_value = {
chess.PAWN: 1, chess.KNIGHT: 3,
chess.BISHOP: 3, chess.ROOK: 5,
chess.QUEEN: 9
}
if board.is_capture(move):
captured_piece = board.piece_at(move.to_square).piece_type
return capture_value.get(captured_piece, 0)
else:
return 0
class TranspositionTable:
def __init__(self):
self.table = {}
def lookup(self, zobrist_key):
return self.table.get(zobrist_key)
def store(self, entry):
self.table[entry.zobrist_key] = entry
class TranspositionTableEntry:
def __init__(self, zobrist_key, depth, score, flag, best_move):
self.zobrist_key = zobrist_key
self.depth = depth
self.score = score
self.flag = flag
self.best_move = best_move
# Constants for transposition table flags
EXACT = 0
LOWER = 1
UPPER = 2
# Initialize the transposition table
transposition_table = TranspositionTable()
def make_move(depth):
try:
book_moves = chess.polyglot.MemoryMappedReader("opening_books/gm2600.bin").weighted_choice(board).move
moves.append(book_moves)
return book_moves
except:
best_evaluated_move = None
best_value = float('-inf')
alpha = float('-inf')
beta = float('inf')
for move in board.legal_moves:
board.push(move)
new_key = update_zobrist_key(move, current_key) # Update the zobrist key
boardValue = -alpha_beta_pruning(-beta, -alpha, depth - 1, new_key) # Pass the new_key
board.pop()
if boardValue > best_value:
best_value = boardValue
best_evaluated_move = move
alpha = max(alpha, boardValue)
moves.append(best_evaluated_move)
return best_evaluated_move
def has_non_pawn_material(board):
non_pawn_material = {
chess.KNIGHT: 3,
chess.BISHOP: 3,
chess.ROOK: 5,
chess.QUEEN: 9
}
total_non_pawn_material = 0
for square, piece in board.piece_map().items():
if piece.piece_type in non_pawn_material:
total_non_pawn_material += non_pawn_material[piece.piece_type]
return total_non_pawn_material >= 10
def quiescence_search(alpha, beta):
stand_pat = evaluation_function()
if stand_pat >= beta:
return beta
if alpha < stand_pat:
alpha = stand_pat
legal_captures = [move for move in board.legal_moves if board.is_capture(move)]
for move in legal_captures:
board.push(move)
score = -quiescence_search(-beta, -alpha)
board.pop()
if score >= beta:
return beta
if score > alpha:
alpha = score
return alpha
def alpha_beta_pruning(alpha, beta, depth, zobrist_key):
tt_entry = transposition_table.lookup(zobrist_key)
if tt_entry and tt_entry.depth >= depth:
if tt_entry.flag == EXACT:
return tt_entry.score
elif tt_entry.flag == LOWER and tt_entry.score >= beta:
return beta
elif tt_entry.flag == UPPER and tt_entry.score <= alpha:
return alpha
if depth == 0:
return quiescence_search(alpha, beta)
legal_moves = list(board.legal_moves)
in_check = board.is_check()
best_score = -float('inf')
# Null move pruning
if depth >= 3 and not in_check and not has_non_pawn_material(board):
null_move_depth = depth - 3
board.push(chess.Move.null())
new_key = update_zobrist_key(chess.Move.null(), zobrist_key)
score = -alpha_beta_pruning(-beta, -beta + 1, null_move_depth, new_key)
board.pop()
if score >= beta:
return beta
# Move ordering
legal_moves.sort(key=lambda move: capture_heuristic(move), reverse=True)
for move in legal_moves:
board.push(move)
new_key = update_zobrist_key(move, zobrist_key)
score = -alpha_beta_pruning(-beta, -alpha, depth - 1, new_key)
board.pop()
best_score = max(best_score, score)
alpha = max(alpha, best_score)
if alpha >= beta:
tt_entry = TranspositionTableEntry(zobrist_key, depth, best_score, EXACT, move)
transposition_table.store(tt_entry)
break
return best_score
def evaluation_function():
white_pawn = len(board.pieces(chess.PAWN, chess.WHITE))
black_pawn = len(board.pieces(chess.PAWN, chess.BLACK))
white_knight = len(board.pieces(chess.KNIGHT, chess.WHITE))
black_knight = len(board.pieces(chess.KNIGHT, chess.BLACK))
white_bishop = len(board.pieces(chess.BISHOP, chess.WHITE))
black_bishop = len(board.pieces(chess.BISHOP, chess.BLACK))
white_rook = len(board.pieces(chess.ROOK, chess.WHITE))
black_rook = len(board.pieces(chess.ROOK, chess.BLACK))
white_queen = len(board.pieces(chess.QUEEN, chess.WHITE))
black_queen = len(board.pieces(chess.QUEEN, chess.BLACK))
if board.is_checkmate():
if board.turn:
return -9999
else:
return 9999
if board.is_insufficient_material() or board.is_stalemate():
return 0
piece_difference = pawn_piece_value * (white_pawn - black_pawn) + knight_piece_value * (white_knight - black_knight) \
+ bishop_piece_value * (white_bishop - black_bishop) + rook_piece_value * (
white_rook - black_rook) \
+ queen_piece_value * (white_queen - black_queen)
piece_types = [chess.PAWN, chess.KNIGHT, chess.BISHOP, chess.ROOK, chess.QUEEN, chess.KING]
color_multiplier = [1, -1]
total_score = 0
for piece_type in piece_types:
for color in color_multiplier:
piece_square_table = None
if piece_type == chess.PAWN:
piece_square_table = pawn_piece_square_table
elif piece_type == chess.KNIGHT:
piece_square_table = knight_piece_square_table
elif piece_type == chess.BISHOP:
piece_square_table = bishop_piece_square_table
elif piece_type == chess.ROOK:
piece_square_table = rook_piece_square_table
elif piece_type == chess.QUEEN:
piece_square_table = queen_piece_square_table
elif piece_type == chess.KING:
piece_square_table = king_piece_square_table_middle_game
for square in board.pieces(piece_type, color):
total_score += color * piece_square_table[square]
if board.turn:
return total_score + piece_difference
else:
return -(total_score + piece_difference)
#----------------------------------------------------#
# THEODORA PLAYS AGAINST ITSELF #
#----------------------------------------------------#
moves = []
board = chess.Board()
number_of_moves = 1
while not board.is_game_over(claim_draw=draw_agreement_allowed):
if board.turn:
board.push(make_move(40))
print(f"The move is: {moves[-1]}\n" f"The number of moves: {number_of_moves}\n"
f"\n" f"{board}\n")
else:
board.push(make_move(40))
print(f"The move is: {moves[-1]}\n" f"The number of moves: {number_of_moves}\n"
f"\n" f"{board}\n")
number_of_moves = number_of_moves + 1
game = chess.pgn.Game()
for key, value in headers.items():
game.headers[key] = value
game.headers["Result"] = str(board.result(claim_draw=draw_agreement_allowed))
game.add_line(moves)
print(game)
#----------------------------------------------------#
# PLAY AGAINST THEODORA #
#----------------------------------------------------#
#moves = []
#board = chess.Board()
#number_of_moves = 1
#
#while not board.is_game_over(claim_draw=draw_agreement_allowed):
#
# if board.turn:
# board.push(make_move(40))
#
# print(f"The move is: {moves[-1]}\n" f"The number of moves: {number_of_moves}\n"
# f"\n" f"{board}\n")
#
# else:
# user_move = input("Enter your move:")
# board.push_san(user_move)
#
# print(f"The move is: {moves[-1]}\n" f"The number of moves: {number_of_moves}\n"
# f"\n" f"{board}\n")
#
# number_of_moves = number_of_moves + 1
#
#game = chess.pgn.Game()
#
#for key, value in headers.items():
# game.headers[key] = value
#
#game.headers["Result"] = str(board.result(claim_draw=draw_agreement_allowed))
#game.add_line(moves)
#print(game)