You can view the final AI algorithm here on GitHub. I’ll demonstrate how each affects the algorithm’s playing style. Let’s explore some basic concepts that will help us create a simple chess AI:Īt each step, we’ll improve our algorithm with one of these time-tested chess-programming techniques. Raise InvalidMoveError('Piece cannot be moved to )'.format(x.x, x.y), moves)))ī.checked_move_piece(knight_square, b.at(2, 0))ī.checked_move_piece(b.at(2, 0), b.at(3, 2))ī.checked_move_piece(b.at(1, 1), b.at(3, 1))ī.checked_move_piece(b.at(1, 2), b.at(2, 2))ī.checked_move_piece(b.at(0, 2), b.at(2, 0))ī.checked_move_piece(b.at(0, 3), b.By Lauri Hartikka A step-by-step guide to building a simple chess AI If to_ordinates not in imap(lambda square: ordinates, Or from_square does not contain a piece, an InvalidMoveError This is checked to ensure that the move is valid for the To the square having coorindates in to_square. Self._squares = Square(from_x, from_y)ĭef checked_move_piece(self, from_square, to_square): Self._squares = Square(to_x, to_y, from_square.piece) Raise InvalidMoveError('No piece exists on the square to move from!') If no piece exists on from_square, an InvalidMoveError is To the square having coordinates in to_square. '''Updates the board by moving the piece in from_square X <= board_size, y <= board_size)):ĭef move_piece(self, from_square, to_square): If all((x >= board_size, y >= board_size, Numbering starts fromĠ, where (0, 0) denotes the left-top hand of the board, and (7, 7)ĭenotes the bottom right hand side of the board. '''Retrives the square at (row x, column y). Self._squares = [Square(7, idx, piece(WHITE)) Self._squares = [Square(0, idx, piece(BLACK)) Order = (Rook, Knight, Bishop, Queen, King, Bishop, Knight, Rook) This is initialized to a default starting '''A Board defines an object that encapsulates the 64 squares ofĪn 8x8 chess board. Rook_moves = rook.enumerate_moves(board, x, y) # Moves for a queen are the union of those from a rookīishop_moves = bishop.enumerate_moves(board, x, y) Return list(chain(x_positive, x_negative, y_positive, y_negative)) (board.at(x, y - n) for n in board_size)) (board.at(x, y + n) for n in board_size)) (board.at(x - n, y) for n in board_size)) (board.at(x + n, y) for n in board_size)) Return list(chain(positive, negative, pos_neg, neg_pos)) (board.at(x - n, y + n) for n in board_size)) (board.at(x + n, y - n) for n in board_size)) (board.at(x - n, y - n) for n in board_size)) (board.at(x + n, y + n) for n in board_size)) If opponent_piece_exists(right_diagonal): Right_diagonal = board.at(x + move_dir, y + 1) Left_diagonal = board.at(x + move_dir, y - 1) # diagonally if there is a piece to take. If board.at(x + move_dir, y).can_move_to(self): # Check if we can move it forward one row Moves.append(board.at(x + 2 * move_dir, y)) # (potentially) move it forward two rows.īoard.at(x + 2 * move_dir, y).is_empty())): # Is the pawn at its starting position? If so, we can Return self._enumerate_moves(board, x, y, start_row, move_dir)ĭef _enumerate_moves(self, board, x, y, start_x_row, move_dir): If other is not None and isinstance(other, InvalidSquare): Have any of the properties (that is x, y, piece). This supports methods that Square supports, but does not '''Class that defines a "non-square" that can be used to signalĪ square that does not exist on the board. Return str(self._piece) if not self.is_empty() else '_' Return all((self.x = other.x, self.y = other.y)) If other is not None and isinstance(other, Square): Return self._piece.enumerate_moves(board, self._x, self._y) Returns a list of moves, or an empty list if the square is '''Enumerates moves for the piece contained on this square. Return self.is_empty() or (self._lour != lour) Returns True if the piece can make the move, False otherwise. That contains a piece of the opposing colour. A piece may move to a square that is empty or '''Checks if the piece passed as an argument can move to '''Returns True if this Square is not populated with, Go from (0, 0) to (7, 7), where (0, 0) is the top left cornerĪnd (7, 7) the bottom right. This is given an x and y co-ordinate,Īnd can optionally be populated with a piece. Super(InvalidMoveError, self)._init_(msg) '''Exception that is raised when an invalid move is '''Ī very simple implementation of a chess board and pieces, mainlyįor the purposes of enumerating all possible moves a piece canįrom itertools import chain, imap, takewhile Note that this doesn't implement en-passant or castling, as these are a bit of a pain. I was going to write an answer for this question, but while I was bashing out some code to throw into an answer, I figured why not build it out completely instead and have it critiqued. There was a question asked recently here that went through enumerating moves for a chess piece.
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