def get_movement_vector(move: chess.Move):
"""
Returns a vector representation for a chess-move.
The first coordinate describes the row offset and the second the column offset.
:param move: Chess move object
:return: Offset of the move [y-offset, x-offset]
"""
from_row, from_col = get_row_col(move.from_square)
to_row, to_col = get_row_col(move.to_square)
return [to_row - from_row, to_col - from_col]
def get_plane_index_from_move(move) -> [int, int, int]:
"""
Computes the index in the move policy matrix for a given move.
Queen moves | 56 -> 0..55
Knight moves | 8 -> 56..63
Promotions | 12 -> 64..75
Drop | 5 -> 76..80
----------------------------
Total 81
:param move: Chess move object
:return: Plane index
"""
if move.drop:
# dropping a piece
piece_type = move.drop
to_row, to_col = get_row_col(move.to_square)
board_offset = get_plane_index_drop_move(piece_type)
return board_offset, to_row, to_col
if move.promotion:
piece_type = move.promotion
movement_vector = get_movement_vector(move)
# a pawn can only move forward or capture to the left or right
# => we only have to inspect the x axis
# python-chess starts counting at 1
from_row, from_col = get_row_col(move.from_square)
board_offset = get_plane_index_promotion_move(piece_type, movement_vector)
return board_offset, from_row, from_col
# normal move
movement_vector = get_movement_vector(move)
from_row, from_col = get_row_col(move.from_square)
absolute_movement_vector = np.abs(movement_vector)
# a knight move can be identified by its special movement behaviour
# only the knight has a '1' and a '2' in its movement vector
is_knight_move = (min(absolute_movement_vector) == 1) and (max(absolute_movement_vector) == 2)
if is_knight_move:
board_offset = get_plane_index_knight_move(movement_vector)
return board_offset, from_row, from_col
move_type_offset = 0
movement_offset = get_plane_index_queen_move(movement_vector)
board_offset = move_type_offset + movement_offset
return board_offset, from_row, from_col
def _fill_position_planes(planes_pos,
board,
board_occ=0,
mode=MODE_CRAZYHOUSE):
# Fill in the piece positions
# Iterate over both color starting with WHITE
for idx, color in enumerate(chess.COLORS):
# the PIECE_TYPE is an integer list in python-chess
for piece_type in chess.PIECE_TYPES:
# define the channel by the piece_type (the input representation uses the same ordering as python-chess)
# we add an offset for the black pieces
# note that we subtract 1 because in python chess the PAWN has index 1 and not 0
channel = (piece_type - 1) + idx * len(chess.PIECE_TYPES)
# iterate over the piece mask and receive every position square of it
for pos in board.pieces(piece_type, color):
row, col = get_row_col(pos)
# set the bit at the right position
planes_pos[channel, row, col] = 1
# (II) Fill in the Repetition Data
# a game to test out if everything is working correctly is: https://lichess.org/jkItXBWy#73
channel = CHANNEL_MAPPING_POS["repetitions"]
# set how often the position has already occurred in the game (default 0 times)
# this is used to check for claiming the 3 fold repetition rule
if board_occ >= 1:
planes_pos[channel, :, :] = 1
if board_occ >= 2:
planes_pos[channel + 1, :, :] = 1
# Fill in the Prisoners / Pocket Pieces
if board.uci_variant == "crazyhouse":
# iterate over all pieces except the king
for p_type in chess.PIECE_TYPES[:-1]:
# p_type -1 because p_type starts with 1
channel = CHANNEL_MAPPING_POS["prisoners"] + p_type - 1
planes_pos[channel, :, :] = board.pockets[chess.WHITE].count(
p_type)
# the prison for black begins 5 channels later
planes_pos[channel +
5, :, :] = board.pockets[chess.BLACK].count(p_type)
# (III) Fill in the promoted pieces
# iterate over all promoted pieces according to the mask and set the according bit
if mode == MODE_CRAZYHOUSE or mode == MODE_LICHESS:
channel = CHANNEL_MAPPING_POS["promo"]
for pos in chess.SquareSet(board.promoted):
row, col = get_row_col(pos)
if board.piece_at(pos).color == chess.WHITE:
planes_pos[channel, row, col] = 1
else:
planes_pos[channel + 1, row, col] = 1
# (III.2) En Passant Square
# mark the square where an en-passant capture is possible
channel = CHANNEL_MAPPING_POS["ep_square"]
if board.ep_square is not None:
row, col = get_row_col(board.ep_square)
planes_pos[channel, row, col] = 1
return planes_pos
def board_to_planes(board,
board_occ=0,
normalize=True,
mode=MODE_CRAZYHOUSE,
last_moves=None):
"""
Gets the plane representation of a given board state.
(No history of past board positions is used.)
:param board: Board handle (Python-chess object)
:param board_occ: Sets how often the board state has occurred before (by default 0)
:param normalize: True if the inputs shall be normalized to the range [0.-1.]
:param mode: 0 - MODE_CRAZYHOUSE: Crazyhouse only specification.
(Visit variants.crazyhouse.input_representation for detailed documentation)
1 - MODE_LICHESS: Specification for all supported variants on lichess.org
(Visit variants.lichess.input_representation for detailed documentation)
2 - MODE_CHESS: Specification for chess only with chess960 support
(Visit variants.chess.input_representation for detailed documentation)
:param last_moves: List of last moves. It is assumed that the most recent move is the first entry !
:return: planes - the plane representation of the current board state
"""
# TODO: Remove board.mirror() for black by addressing the according color channel
# (I) Define the Input Representation for one position
planes_pos = np.zeros((NB_CHANNELS_POS, BOARD_HEIGHT, BOARD_WIDTH))
planes_const = np.zeros((NB_CHANNELS_CONST, BOARD_HEIGHT, BOARD_WIDTH))
if mode == MODE_CRAZYHOUSE:
# crazyhouse only doesn't contain remaining checks
planes_variants = False
elif mode == MODE_LICHESS:
planes_variants = np.zeros(
(NB_CHANNELS_VARIANTS, BOARD_HEIGHT, BOARD_WIDTH))
else: # mode = MODE_CHESS
# chess doesn't contain pocket pieces and remaining checks
planes_variants = np.zeros(
(NB_CHANNELS_VARIANTS, BOARD_HEIGHT, BOARD_WIDTH))
# save whose turn it is
board_turn = chess.WHITE
# check who's player turn it is and flip the board if it's black turn
if board.turn == chess.BLACK:
board_turn = chess.BLACK
board = board.mirror()
_fill_position_planes(planes_pos, board, board_occ, mode)
_fill_constant_planes(planes_const, board, board_turn)
if mode == MODE_LICHESS:
_fill_variants_plane(board, planes_variants)
elif mode == MODE_CHESS:
if board.chess960 is True:
planes_variants[:, :, :] = 1
# create the move planes
planes_moves = np.zeros((NB_CHANNELS_HISTORY, BOARD_HEIGHT, BOARD_WIDTH))
if last_moves:
for i, move in enumerate(last_moves):
if move:
from_row, from_col = get_row_col(
move.from_square, mirror=board_turn == chess.BLACK)
to_row, to_col = get_row_col(move.to_square,
mirror=board_turn == chess.BLACK)
planes_moves[i * 2, from_row, from_col] = 1
planes_moves[i * 2 + 1, to_row, to_col] = 1
# (VI) Merge the Matrix-Stack
if mode == MODE_CRAZYHOUSE:
planes = np.concatenate((planes_pos, planes_const), axis=0)
else: # mode = MODE_LICHESS | mode == MODE_CHESS
planes = np.concatenate(
(planes_pos, planes_const, planes_variants, planes_moves), axis=0)
# revert the board if the players turn was black
# ! DO NOT DELETE OR UNCOMMENT THIS BLOCK BECAUSE THE PARAMETER board IS CHANGED IN PLACE !
if board_turn == chess.BLACK:
board = board.mirror()
if normalize is True:
planes *= MATRIX_NORMALIZER
# planes = normalize_input_planes(planes)
# return the plane representation of the given board
return planes
def board_to_planes(board: chess.Board, normalize=True, last_moves=None):
"""
Gets the plane representation of a given board state.
## Chess:
Feature | Planes
--- | ---
P1 piece | 6 (pieces are ordered: PAWN, KNIGHT, BISHOP, ROOK, QUEEN, KING)
P2 piece | 6 (pieces are ordered: PAWN, KNIGHT, BISHOP, ROOK, QUEEN, KING)
En-passant square | 1 (Binary map indicating the square where en-passant capture is possible)
---
13 planes
* * *
P1 castling | 2 (One if castling is possible, else zero)
P2 castling | 2 (One if castling is possible, else zero)
---
4 planes
* * *
Last 8 moves | 16 (indicated by origin and destination square, the most recent move is described by first 2 planes)
---
16 planes
* * *
is960 = | 1 (boolean, 1 when active)
---
1 plane
---
P1 pieces | 1 | A grouped mask of all WHITE pieces |
P2 pieces | 1 | A grouped mask of all BLACK pieces |
Checkerboard | 1 | A chess board pattern |
P1 Material Diff | 5 | (pieces are ordered: PAWN, KNIGHT, BISHOP, ROOK, QUEEN), normalized with 8, + means positive, - means negative |
Opposite Color Bishops | 1 | Indicates if they are only two bishops and the bishops are opposite color |
Checkers | 1 | Indicates all pieces giving check |
Checking Moves | 2 | Indicates all checking moves (from sq, to sq) |
Mobility | 1 | Indicates the number of legal moves
P1 Material Count | 5 | (pieces are ordered: PAWN, KNIGHT, BISHOP, ROOK, QUEEN), normalized with 8 |
---
18 planes
The total number of planes is calculated as follows:
# --------------
13 + 4 + 2 + 1 + 18
Total: 38 planes
:param board: Board handle (Python-chess object)
:param normalize: True if the inputs shall be normalized to the range [0.-1.]
:param last_moves: List of last last moves. The most recent move is the first entry.
:return: planes - the plane representation of the current board state
"""
# return the plane representation of the given board
# return variants.board_to_planes(board, board_occ, normalize, mode=MODE_CHESS)
planes = np.zeros((NB_CHANNELS_TOTAL, BOARD_HEIGHT, BOARD_WIDTH))
# channel will be incremented by 1 at first plane
channel = 0
me = board.turn
you = not board.turn
colors = [me, you]
# mirror all bitboard entries for the black player
mirror = board.turn == chess.BLACK
assert (channel == CHANNEL_PIECES)
# Fill in the piece positions
# Channel: 0 - 11
# Iterate over both color starting with WHITE
for color in colors:
# the PIECE_TYPE is an integer list in python-chess
for piece_type in chess.PIECE_TYPES:
# iterate over the piece mask and receive every position square of it
for pos in board.pieces(piece_type, color):
row, col = get_row_col(pos, mirror=mirror)
# set the bit at the right position
planes[channel, row, col] = 1
channel += 1
# Channel: 12
# En Passant Square
assert (channel == CHANNEL_EN_PASSANT)
if board.ep_square and board.has_legal_en_passant(): # is not None:
row, col = get_row_col(board.ep_square, mirror=mirror)
planes[channel, row, col] = 1
channel += 1
# Channel: 13 - 16
assert (channel == CHANNEL_CASTLING)
for color in colors:
# check for King Side Castling
if board.has_kingside_castling_rights(color):
planes[channel, :, :] = 1
channel += 1
# check for Queen Side Castling
if board.has_queenside_castling_rights(color):
planes[channel, :, :] = 1
channel += 1
# Channel: 17 - 18
assert (channel == CHANNEL_LAST_MOVES)
# Last 8 moves
if last_moves:
assert (len(last_moves) == NB_LAST_MOVES)
for move in last_moves:
if move:
from_row, from_col = get_row_col(move.from_square,
mirror=mirror)
to_row, to_col = get_row_col(move.to_square, mirror=mirror)
planes[channel, from_row, from_col] = 1
channel += 1
planes[channel, to_row, to_col] = 1
channel += 1
else:
channel += 2
else:
channel += NB_LAST_MOVES * NB_CHANNELS_PER_HISTORY_ITEM
# Channel: 19
# Chess960
assert (channel == CHANNEL_IS_960)
if board.chess960:
planes[channel + 1, :, :] = 1
channel += 1
# Channel: 20 - 21
# All white pieces and black pieces in a single map
assert (channel == CHANNEL_PIECE_MASK)
for color in colors:
# the PIECE_TYPE is an integer list in python-chess
for piece_type in chess.PIECE_TYPES:
# iterate over the piece mask and receive every position square of it
for pos in board.pieces(piece_type, color):
row, col = get_row_col(pos, mirror=mirror)
# set the bit at the right position
planes[channel, row, col] = 1
channel += 1
# Channel: 22
# Checkerboard
assert (channel == CHANNEL_CHECKERBOARD)
planes[channel, :, :] = checkerboard()
channel += 1
# Channel: 23 - 27
# Relative material difference (negative if less pieces than opponent and positive if more)
# iterate over all pieces except the king
assert (channel == CHANNEL_MATERIAL_DIFF)
for piece_type in chess.PIECE_TYPES[:-1]:
material_count = len(board.pieces(piece_type, me)) - len(
board.pieces(piece_type, you))
planes[
channel, :, :] = material_count / NORMALIZE_PIECE_NUMBER if normalize else material_count
channel += 1
# Channel: 28
# Opposite color bishops
assert (channel == CHANNEL_OPP_BISHOPS)
if opposite_colored_bishops(board):
planes[channel, :, :] = 1
channel += 1
# Channel: 29
# Checkers
assert channel == CHANNEL_CHECKERS
board_checkers = checkers(board)
if board_checkers:
# iterate over the piece mask and receive every position square of it
for pos in chess.SquareSet(board_checkers):
row, col = get_row_col(pos, mirror=mirror)
# set the bit at the right position
planes[channel, row, col] = 1
channel += 1
my_legal_moves = list(board.legal_moves)
# Channel: 30 - 31
assert channel == CHANNEL_CHECK_MOVES
for move in my_legal_moves:
if gives_check(board, move):
row, col = get_row_col(move.from_square, mirror=mirror)
planes[channel, row, col] = 1
row, col = get_row_col(move.to_square, mirror=mirror)
planes[channel + 1, row, col] = 1
channel += 2
# Channel: 32
# Mobility
assert (channel == CHANNEL_MOBILITY)
planes[channel, :, :] = len(
my_legal_moves) / NORMALIZE_MOBILITY if normalize else len(
my_legal_moves)
channel += 1
# Channel: 33
# Material
assert (channel == CHANNEL_MATERIAL_COUNT)
for piece_type in chess.PIECE_TYPES[:-1]:
material_count = len(board.pieces(piece_type, me))
planes[
channel, :, :] = material_count / NORMALIZE_PIECE_NUMBER if normalize else material_count
channel += 1
assert channel == NB_CHANNELS_TOTAL
return planes
def board_to_planes(board, board_occ=0, normalize=True):
"""
Gets the plane representation of a given board state.
(Now history of past board positions is used.)
## Crazyhouse:
Feature | Planes
--- | ---
P1 piece | 6 (pieces are ordered: PAWN, KNIGHT, BISHOP, ROOK, QUEEN, KING)
P2 piece | 6 (pieces are ordered: PAWN, KNIGHT, BISHOP, ROOK, QUEEN, KING)
Repetitions | 2 (two planes (full zeros/ones) indicating how often the board positions has occurred)
P1 prisoner count | 5 (pieces are ordered: PAWN, KNIGHT, BISHOP, ROOK, QUEEN) (excluding the KING)
P2 prisoner count | 5 (pieces are ordered: PAWN, KNIGHT, BISHOP, ROOK, QUEEN) (excluding the KING)
P1 Promoted Pawns Mask | 1 (binary map indicating the pieces which have been promoted)
P2 Promoted Pawns Mask | 1 (binary map indicating the pieces which have been promoted)
En-passant square | 1 (Binary map indicating the square where en-passant capture is possible)
---
27 planes
* * *
Colour | 1 (all zeros for black and all ones for white)
Total move count | 1 (integer value setting the move count (uci notation))
P1 castling | 2 (One if castling is possible, else zero)
P2 castling | 2 (One if castling is possible, else zero)
No-progress count | 1 (Setting the no progress counter as integer values, (described by uci halfmoves format)
# --------------
7 planes
The history list of the past 7 board states have been removed
The total number of planes is calculated as follows:
27 + 7
Total: 34 planes
:param board: Board handle (Python-chess object)
:param board_occ: Sets how often the board state has occurred before (by default 0)
:param normalize: True if the inputs shall be normalized to the range [0.-1.]
:return: planes - the plane representation of the current board state
"""
# TODO: Remove board.mirror() for black by addressing the according color channel
# (I) Define the Input Representation for one position
planes_pos = np.zeros((NB_CHANNELS_POS, BOARD_HEIGHT, BOARD_WIDTH))
planes_const = np.zeros((NB_CHANNELS_CONST, BOARD_HEIGHT, BOARD_WIDTH))
# save whose turn it is
board_turn = chess.WHITE
# check who's player turn it is and flip the board if it's black turn
if board.turn == chess.BLACK:
board_turn = chess.BLACK
board = board.mirror()
# Fill in the piece positions
# Iterate over both color starting with WHITE
for z, color in enumerate(chess.COLORS):
# the PIECE_TYPE is an integer list in python-chess
for piece_type in chess.PIECE_TYPES:
# define the channel by the piecetype (the input representation uses the same ordering as python-chess)
# we add an offset for the black pieces
# note that we subtract 1 because in python chess the PAWN has index 1 and not 0
channel = (piece_type - 1) + z * len(chess.PIECE_TYPES)
# iterate over the piece mask and receive every position square of it
for pos in board.pieces(piece_type, color):
row, col = get_row_col(pos)
# set the bit at the right position
planes_pos[channel, row, col] = 1
# (II) Fill in the Repetition Data
# a game to test out if everything is working correctly is: https://lichess.org/jkItXBWy#73
ch = CHANNEL_MAPPING_POS["repetitions"]
# set how often the position has already occurred in the game (default 0 times)
# this is used to check for claiming the 3 fold repetition rule
if board_occ >= 1:
planes_pos[ch, :, :] = 1
if board_occ >= 2:
planes_pos[ch + 1, :, :] = 1
# Fill in the Prisoners / Pocket Pieces
# iterate over all pieces except the king
for p_type in chess.PIECE_TYPES[:-1]:
# p_type -1 because p_type starts with 1
ch = CHANNEL_MAPPING_POS["prisoners"] + p_type - 1
planes_pos[ch, :, :] = board.pockets[chess.WHITE].count(p_type)
# the prison for black begins 5 channels later
planes_pos[ch + 5, :, :] = board.pockets[chess.BLACK].count(p_type)
# (III) Fill in the promoted pieces
# iterate over all promoted pieces according to the mask and set the according bit
ch = CHANNEL_MAPPING_POS["promo"]
for pos in chess.SquareSet(board.promoted):
row, col = get_row_col(pos)
if board.piece_at(pos).color == chess.WHITE:
planes_pos[ch, row, col] = 1
else:
planes_pos[ch + 1, row, col] = 1
# (III.2) En Passant Square
# mark the square where an en-passant capture is possible
ch = CHANNEL_MAPPING_POS["ep_square"]
if board.ep_square is not None:
row, col = get_row_col(board.ep_square)
planes_pos[ch, row, col] = 1
# (IV) Constant Value Inputs
# (IV.1) Color
if board_turn == chess.WHITE:
planes_const[CHANNEL_MAPPING_CONST["color"], :, :] = 1
# otherwise the mat will remain zero
# (IV.2) Total Move Count
planes_const[
CHANNEL_MAPPING_CONST["total_mv_cnt"], :, :] = board.fullmove_number
# alternatively, you could use the half-moves-counter: len(board.move_stack)
# (IV.3) Castling Rights
ch = CHANNEL_MAPPING_CONST["castling"]
# WHITE
# check for King Side Castling
if bool(board.castling_rights & chess.BB_H1) is True:
# White can castle with the h1 rook
planes_const[ch, :, :] = 1
# check for Queen Side Castling
if bool(board.castling_rights & chess.BB_A1) is True:
planes_const[ch + 1, :, :] = 1
# BLACK
# check for King Side Castling
if bool(board.castling_rights & chess.BB_H8) is True:
# White can castle with the h1 rook
planes_const[ch + 2, :, :] = 1
# check for Queen Side Castling
if bool(board.castling_rights & chess.BB_A8) is True:
planes_const[ch + 3, :, :] = 1
# (IV.4) No Progress Count
# define a no 'progress' counter
# it gets incremented by 1 each move
# however, whenever a piece gets dropped, a piece is captured or a pawn is moved, it is reset to 0
# halfmove_clock is an official metric in fen notation
# -> see: https://en.wikipedia.org/wiki/Forsyth%E2%80%93Edwards_Notation
no_progress_cnt = board.halfmove_clock
# check how often the position has already occurred in the game
planes_const[
CHANNEL_MAPPING_CONST["no_progress_cnt"], :, :] = no_progress_cnt
# (V) Merge the Matrix-Stack
planes = np.concatenate((planes_pos, planes_const), axis=0)
# revert the board if the players turn was black
# ! DO NOT DELETE OR UNCOMMENT THIS BLOCK BECAUSE THE PARAMETER board IS CHANGED IN PLACE !
if board_turn == chess.BLACK:
board = board.mirror()
if normalize is True:
planes *= MATRIX_NORMALIZER
# planes = normalize_input_planes(planes)
# return the plane representation of the given board
return planes
def board_to_planes(board: chess.Board,
board_occ,
normalize=True,
last_moves=None):
"""
Gets the plane representation of a given board state.
## Chess:
Feature | Planes
--- | ---
P1 piece | 6 (pieces are ordered: PAWN, KNIGHT, BISHOP, ROOK, QUEEN, KING)
P2 piece | 6 (pieces are ordered: PAWN, KNIGHT, BISHOP, ROOK, QUEEN, KING)
Repetitions | 2 (two planes (full zeros/ones) indicating how often the board positions has occurred)
En-passant square | 1 (Binary map indicating the square where en-passant capture is possible)
---
15 planes
* * *
P1 castling | 2 (One if castling is possible, else zero)
P2 castling | 2 (One if castling is possible, else zero)
No-progress count | 1 (Setting the no progress counter as integer values, (described by uci halfmoves format)
---
5 planes
* * *
Last 8 moves | 16 (indicated by origin and destination square, the most recent move is described by first 2 planes)
---
16 planes
* * *
is960 = | 1 (boolean, 1 when active)
---
1 plane
---
P1 pieces | 1 | A grouped mask of all WHITE pieces |
P2 pieces | 1 | A grouped mask of all BLACK pieces |
Checkerboard | 1 | A chess board pattern |
P1 Material Diff | 5 | (pieces are ordered: PAWN, KNIGHT, BISHOP, ROOK, QUEEN), normalized with 8, + means positive, - means negative |
Opposite Color Bishops | 1 | Indicates if they are only two bishops and the bishops are opposite color |
Checkers | 1 | Indicates all pieces giving check |
P1 Material Count | 5 | (pieces are ordered: PAWN, KNIGHT, BISHOP, ROOK, QUEEN), normalized with 8 |
---
15 planes
The total number of planes is calculated as follows:
# --------------
15 + 5 + 16 + 1 + 15
Total: 52 planes
:param board: Board handle (Python-chess object)
:param board_occ: Number of board occurences
:param normalize: True if the inputs shall be normalized to the range [0.-1.]
:param last_moves: List of last last moves. The most recent move is the first entry.
:return: planes - the plane representation of the current board state
"""
# return the plane representation of the given board
# return variants.board_to_planes(board, board_occ, normalize, mode=MODE_CHESS)
planes = np.zeros((NB_CHANNELS_TOTAL, BOARD_HEIGHT, BOARD_WIDTH))
# channel will be incremented by 1 at first plane
channel = 0
me = board.turn
you = not board.turn
colors = [me, you]
# mirror all bitboard entries for the black player
mirror = board.turn == chess.BLACK
assert channel == CHANNEL_PIECES
# Fill in the piece positions
# Channel: 0 - 11
# Iterate over both color starting with WHITE
for color in colors:
# the PIECE_TYPE is an integer list in python-chess
for piece_type in chess.PIECE_TYPES:
# iterate over the piece mask and receive every position square of it
for pos in board.pieces(piece_type, color):
row, col = get_row_col(pos, mirror=mirror)
# set the bit at the right position
planes[channel, row, col] = 1
channel += 1
assert channel == CHANNEL_REPETITION
# Channel: 12 - 13
# set how often the position has already occurred in the game (default 0 times)
# this is used to check for claiming the 3 fold repetition rule
if board_occ >= 1:
planes[channel, :, :] = 1
if board_occ >= 2:
planes[channel + 1, :, :] = 1
channel += 2
# Channel: 14
# En Passant Square
assert channel == CHANNEL_EN_PASSANT
if board.ep_square and board.has_legal_en_passant(): # is not None:
row, col = get_row_col(board.ep_square, mirror=mirror)
planes[channel, row, col] = 1
channel += 1
# Channel: 15 - 18
assert channel == CHANNEL_CASTLING
for color in colors:
# check for King Side Castling
if board.has_kingside_castling_rights(color):
planes[channel, :, :] = 1
channel += 1
# check for Queen Side Castling
if board.has_queenside_castling_rights(color):
planes[channel, :, :] = 1
channel += 1
# Channel: 19
# (IV.4) No Progress Count
# define a no 'progress' counter
# it gets incremented by 1 each move
# however, whenever a piece gets dropped, a piece is captured or a pawn is moved, it is reset to 0
# halfmove_clock is an official metric in fen notation
# -> see: https://en.wikipedia.org/wiki/Forsyth%E2%80%93Edwards_Notation
# check how often the position has already occurred in the game
assert channel == CHANNEL_NO_PROGRESS
planes[
channel, :, :] = board.halfmove_clock / NORMALIZE_50_MOVE_RULE if normalize else board.halfmove_clock
channel += 1
# Channel: 20 - 35
assert channel == CHANNEL_LAST_MOVES
# Last 8 moves
if last_moves:
assert (len(last_moves) == NB_LAST_MOVES)
for move in last_moves:
if move:
from_row, from_col = get_row_col(move.from_square,
mirror=mirror)
to_row, to_col = get_row_col(move.to_square, mirror=mirror)
planes[channel, from_row, from_col] = 1
channel += 1
planes[channel, to_row, to_col] = 1
channel += 1
else:
channel += 2
else:
channel += NB_LAST_MOVES * NB_CHANNELS_PER_HISTORY_ITEM
# Channel: 36
# Chess960
assert channel == CHANNEL_IS_960
if board.chess960:
planes[channel + 1, :, :] = 1
channel += 1
# Channel: 37 - 38
# All white pieces and black pieces in a single map
assert channel == CHANNEL_PIECE_MASK
for color in colors:
# the PIECE_TYPE is an integer list in python-chess
for piece_type in chess.PIECE_TYPES:
# iterate over the piece mask and receive every position square of it
for pos in board.pieces(piece_type, color):
row, col = get_row_col(pos, mirror=mirror)
# set the bit at the right position
planes[channel, row, col] = 1
channel += 1
# Channel: 39
# Checkerboard
assert (channel == CHANNEL_CHECKERBOARD)
planes[channel, :, :] = checkerboard()
channel += 1
# Channel: 40 - 44
# Relative material difference (negative if less pieces than opponent and positive if more)
# iterate over all pieces except the king
assert channel == CHANNEL_MATERIAL_DIFF
for piece_type in chess.PIECE_TYPES[:-1]:
material_count = len(board.pieces(piece_type, me)) - len(
board.pieces(piece_type, you))
planes[
channel, :, :] = material_count / NORMALIZE_PIECE_NUMBER if normalize else material_count
channel += 1
# Channel: 45
# Opposite color bishops
assert (channel == CHANNEL_OPP_BISHOPS)
if opposite_colored_bishops(board):
planes[channel, :, :] = 1
channel += 1
# Channel: 46
# Checkers
assert channel == CHANNEL_CHECKERS
board_checkers = checkers(board)
if board_checkers:
# iterate over the piece mask and receive every position square of it
for pos in chess.SquareSet(board_checkers):
row, col = get_row_col(pos, mirror=mirror)
# set the bit at the right position
planes[channel, row, col] = 1
channel += 1
# Channel: 47 - 51
# Material
assert channel == CHANNEL_MATERIAL_COUNT
for piece_type in chess.PIECE_TYPES[:-1]:
material_count = len(board.pieces(piece_type, me))
planes[
channel, :, :] = material_count / NORMALIZE_PIECE_NUMBER if normalize else material_count
channel += 1
assert channel == NB_CHANNELS_TOTAL
return planes