"AttributeError: 'str' object has no attribute 'tobytes'" error when running chess_alphazero_sp_mode_config.py

[hzpro1221]

Hi... I encountered this error when running chess_alphazero_sp_mode_config.py. I think something went wrong with chess environment.

Traceback (most recent call last):
File "/content/LightZero/zoo/board_games/chess/config/chess_alphazero_sp_mode_config.py", line 113, in
train_alphazero([main_config, create_config], seed=0, max_env_step=max_env_step)
File "/content/LightZero/lzero/entry/train_alphazero.py", line 119, in train_alphazero
new_data = collector.collect(train_iter=learner.train_iter, policy_kwargs=collect_kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/content/LightZero/lzero/worker/alphazero_collector.py", line 221, in collect
policy_output = self.policy.forward(obs, temperature)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/dist-packages/torch/utils/_contextlib.py", line 116, in decorate_context
return func(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^
File "/content/LightZero/lzero/policy/alphazero.py", line 267, in _forward_collect
action, mcts_probs, root = self._collect_mcts.get_next_action(state_config_for_simulation_env_reset, self._policy_value_fn, self.collect_mcts_temperature, True)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'str' object has no attribute 'tobytes'
Exception ignored in: <function AlphaZeroCollector.del at 0x7d9547da9b20>

[puyuan1996]

Hello, thanks for reporting the issue. We found that the problem arises because the chess environment returns obs['board'] in FEN string format, instead of the expected format. To address this, we have opened a [pull request](#364) where a partial fix（have fixed the AttributeError you mentioned）has already been implemented, and work is still in progress.

We appreciate your feedback and patience. We will keep you updated as soon as new developments are available.

[puyuan1996]

Hello,

If you encounter an error similar to the following after running for a while:

File "/usr/local/lib/python3.11/site-packages/pettingzoo/classic/chess/chess_utils.py", line 251, in get_observation
    result[AUX_OFF + 5].add(board.halfmove_clock // 2)
File "/usr/local/lib/python3.11/site-packages/chess/init.py", line 4069, in add
    self.mask |= BB_SQUARES[square]
                   ~~~~~~~~^^^^^^^^
IndexError: list index out of range

please apply the following modification in /usr/local/lib/python3.11/site-packages/pettingzoo/classic/chess/chess_utils.py:

From:

result[AUX_OFF + 5].add(board.halfmove_clock // 2)

To:

halfmove_square = min(board.halfmove_clock // 2, 63)
result[AUX_OFF + 5].add(halfmove_square)

This update ensures that the value passed to the add function does not exceed the maximum valid index (63). Please note that while this adjustment allows the chess environment to run without encountering the error, it has not undergone full testing. We welcome further discussion or feedback on this issue if you're interested in exploring it deeper.

Thank you for your support and contributions!