Game Environments

class AlphaZero.env.go.GameState(size=19, komi=7.5, enforce_superko=False, history_length=8)

State of a game of Go and some basic functions to interact with it

get_group(position)

Get the group of connected same-color stones to the given position.

Parameters:
  • position – a tuple of (x, y), x being the column index of the starting position of the search,
  • being the row index of the starting position of the search (y) –
Returns:

a set of tuples consist of (x, y)s which are the same-color cluster, which contains the input single position. len(group) is size of the cluster, can be large.
Return type:

set
get_groups_around(position)

returns a list of the unique groups adjacent to position ‘unique’ means that, for example in this position:

. . . . .
. B W . .
. W W . .
. . . . .
. . . . .

only the one white group would be returned on get_groups_around((1,1))

Parameters:position – a tuple of (x, y)
Returns:a list of the unique groups adjacent to position.
Return type:list
copy()

Gets a copy of this Game state

Returns:a copy of this Game state
Return type:AlphaZero.env.go.GameState
is_suicide(action)
Parameters:action – a tuple of (x, y)
Returns:return true if having current_player play at <action> would be suicide
Return type:bool
is_positional_superko(action)

Find all actions that the current_player has done in the past, taking into account the fact that history starts with BLACK when there are no handicaps or with WHITE when there are. :param action: a tuple of (x, y)

Returns:if the move is positional superko.
Return type:bool

Determines if the given action (x,y) is a legal move :param action: a tuple of (x, y)

Returns:if the move is legal.
Return type:bool
is_eyeish(position, owner)
Parameters:
  • position – a tuple of (x, y)
  • owner – the color
Returns:

whether the position is empty and is surrounded by all stones of ‘owner’
Return type:

bool
is_eye(position, owner, stack=[])

returns whether the position is a true eye of ‘owner’ Requires a recursive call; empty spaces diagonal to ‘position’ are fine as long as they themselves are eyes

Parameters:include_eyes – whether to include eyes in legal moves
Returns:a list of tuples.
Return type:list
get_winner()

Calculate score of board state and return player ID (1, -1, or 0 for tie) corresponding to winner. Uses ‘Area scoring’.

Returns:the color of the winner.
Return type:int
place_handicaps(actions)

Place handicap stones of black. :param actions: a list of tuples of (x, y)

Returns:None
place_handicap_stone(action, color=1)

Place a handicap stone of the specified color. :param action: a tuple of (x, y) :param color: the color of the move

Returns:None
get_current_player()
Returns:the color of the player who will make the next move.
Return type:int
do_move(action, color=None)

Play stone at action=(x,y). If color is not specified, current_player is used If it is a legal move, current_player switches to the opposite color If not, an IllegalMove exception is raised

Parameters:
  • action – a tuple of (x, y)
  • color – the color of the move
Returns:

if it is the end of game.
Return type:

bool
transform(transform_id)
Transform the current board and the history boards according to D(4).
Caution: self.history (action history) is not modified, thus this function should ONLY be used for state evaluation.
Parameters:transform_id – integer in range [0, 7]
Returns:None
exception AlphaZero.env.go.IllegalMove
class AlphaZero.env.mnk.GameState(history_length=8)

Game state of mnk Game.

copy()

Gets a copy of this Game state

Returns:a copy of this Game state
Return type:AlphaZero.env.mnk.GameState

Determines if the given action (x,y) is a legal move :param action: a tuple of (x, y)

Returns:if the move is legal.
Return type:bool
Returns:a list of legal moves.
Return type:list
get_winner()

Returns: The winner, None if the game is not ended yet

do_move(action, color=None)

Play stone at action=(x,y). If color is not specified, current_player is used If it is a legal move, current_player switches to the opposite color If not, an IllegalMove exception is raised

Parameters:
  • action – a tuple of (x, y)
  • color – the color of the move
Returns:

if it is the end of game.
Return type:

bool
transform(transform_id)
Transform the current board and the history boards according to D(4).
Caution: self.history (action history) is not modified, thus this function should ONLY be used for state evaluation.
Parameters:transform_id – integer in range [0, 7]
Returns:None
exception AlphaZero.env.mnk.IllegalMove
class AlphaZero.env.reversi.GameState(size=8, history_length=8)

Game state of Reversi Game.

copy()

Gets a copy of this Game state

Returns:a copy of this Game state
Return type:AlphaZero.env.reversi.GameState

Determines if the given action (x,y) is a legal move :param action: a tuple of (x, y)

Returns:if the move is legal.
Return type:bool
This function is infrequently used, therefore not optimized.
Checks all non-pass moves
Returns:a list of legal moves
Return type:list
get_winner()

Counts the stones on the board, assumes the game is ended

Returns:The winner, None if the game is not ended yet
Return type:int
do_move(action, color=None)

Play stone at action=(x,y). If color is not specified, current_player is used If it is a legal move, current_player switches to the opposite color If not, an IllegalMove exception is raised

Parameters:
  • action – a tuple of (x, y)
  • color – the color of the move
Returns:

if it is the end of game.
Return type:

bool
transform(transform_id)
Transform the current board and the history boards according to D(4).
Caution: self.history (action history) is not modified, thus this function should ONLY be used for state evaluation.
Parameters:transform_id – integer in range [0, 7]
Returns:None
exception AlphaZero.env.reversi.IllegalMove