pass parameters to chess engine

[sugizo]

background
want to use lc0 to analyse chess in google colab

tried 0
/bin/lc0

result

WARNING:chess.engine:<UciProtocol (pid=23956)>: stderr >>        _
WARNING:chess.engine:<UciProtocol (pid=23956)>: stderr >> |   _ | |
WARNING:chess.engine:<UciProtocol (pid=23956)>: stderr >> |_ |_ |_| v0.26.3 built Apr 25 2023
WARNING:chess.engine:<UciProtocol (pid=23956)>: stderr >> Creating backend [cudnn-auto]...
WARNING:chess.engine:<UciProtocol (pid=23956)>: stderr >> Switching to [cudnn]...
WARNING:chess.engine:<UciProtocol (pid=23956)>: Unexpected engine output: 'error The cudnn backend requires a network file.'
WARNING:chess.engine:<UciProtocol (pid=23956)>: stderr >> Creating backend [cudnn-auto]...
WARNING:chess.engine:<UciProtocol (pid=23956)>: stderr >> Switching to [cudnn]...
WARNING:chess.engine:<UciProtocol (pid=23956)>: Unexpected engine output: 'error The cudnn backend requires a network file.'
ERROR:asyncio:Exception in callback BaseSubprocessTransport._call_connection_lost(None)
handle: <Handle BaseSubprocessTransport._call_connection_lost(None)>
Traceback (most recent call last):
  File "/usr/lib/python3.9/asyncio/events.py", line 80, in _run
    self._context.run(self._callback, *self._args)
  File "/usr/lib/python3.9/asyncio/base_subprocess.py", line 248, in _call_connection_lost
    self._protocol.connection_lost(exc)
  File "/usr/local/lib/python3.9/dist-packages/chess/engine.py", line 1011, in connection_lost
    self.command._engine_terminated(self, code)
  File "/usr/local/lib/python3.9/dist-packages/chess/engine.py", line 1260, in _engine_terminated
    self.engine_terminated(engine, exc)
  File "/usr/local/lib/python3.9/dist-packages/chess/engine.py", line 1746, in engine_terminated
    self.analysis.set_exception(exc)
  File "/usr/local/lib/python3.9/dist-packages/chess/engine.py", line 2573, in set_exception
    self._finished.set_exception(exc)
asyncio.exceptions.InvalidStateError: invalid state
---------------------------------------------------------------------------
CancelledError                            Traceback (most recent call last)
[/usr/local/lib/python3.9/dist-packages/chess/engine.py](https://localhost:8080/#) in analyse(self, board, limit, multipv, game, info, root_moves, options)
   1186         with analysis:
-> 1187             await analysis.wait()
   1188 

8 frames
CancelledError: 

During handling of the above exception, another exception occurred:

CancelledError                            Traceback (most recent call last)
CancelledError: 

The above exception was the direct cause of the following exception:

TimeoutError                              Traceback (most recent call last)
[/usr/lib/python3.9/asyncio/tasks.py](https://localhost:8080/#) in wait_for(fut, timeout, loop)
    490                 return fut.result()
    491             except exceptions.CancelledError as exc:
--> 492                 raise exceptions.TimeoutError() from exc
    493     finally:
    494         timeout_handle.cancel()

TimeoutError:

root cause
when trying to use lc0 chess engine it need to pass parameter weight files

tried 1
/bin/lc0 -w /content/lc0-net

result

FileNotFoundError                         Traceback (most recent call last)
[<ipython-input-78-58a359f42c25>](https://localhost:8080/#) in on_change_engine_1(self, change)
    118         with self.output_board_info:
    119             clear_output(wait = True)
--> 120             display(HTML(self.display_board_info(self.board) ) )
    121 
    122     def on_change_engine_2(self, change):

17 frames
[/usr/lib/python3.9/subprocess.py](https://localhost:8080/#) in _execute_child(self, args, executable, preexec_fn, close_fds, pass_fds, cwd, env, startupinfo, creationflags, shell, p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite, restore_signals, gid, gids, uid, umask, start_new_session)
   1819                     if errno_num != 0:
   1820                         err_msg = os.strerror(errno_num)
-> 1821                     raise child_exception_type(errno_num, err_msg, err_filename)
   1822                 raise child_exception_type(err_msg)
   1823 

FileNotFoundError: [Errno 2] No such file or directory: '/bin/lc0 -w /content/lc0-net'

question
how to using lc0 with parameter weight file in python chess ?

thanks and best regards

[niklasf]

The command parameter is equivalent to args in subprocess.Popen. Use:

await chess.engine.popen_uci(["/bin/lc0", "-w", "/content/lc0-net"])

or

chess.engine.SimpleEngine.popen_uci(["/bin/lc0", "-w", "/content/lc0-net"])