issue with multi processing

[sadimoodi]

Hello @AminHP ,
when running one of your examples (Create an environment with custom parameters), i get the follwoing error:
File "", line 1, in
File "C:\Users\Ali.Khankan\AppData\Roaming\Python\Python39\site-packages\multiprocess\spawn.py", line 116, in spawn_main
exitcode = _main(fd, parent_sentinel)
File "C:\Users\Ali.Khankan\AppData\Roaming\Python\Python39\site-packages\multiprocess\spawn.py", line 125, in _main
prepare(preparation_data)
File "C:\Users\Ali.Khankan\AppData\Roaming\Python\Python39\site-packages\multiprocess\spawn.py", line 236, in prepare
_fixup_main_from_path(data['init_main_from_path'])
File "C:\Users\Ali.Khankan\AppData\Roaming\Python\Python39\site-packages\multiprocess\spawn.py", line 287, in _fixup_main_from_path
main_content = runpy.run_path(main_path,
File "C:\Program Files\Python39\lib\runpy.py", line 268, in run_path
return _run_module_code(code, init_globals, run_name,
File "C:\Program Files\Python39\lib\runpy.py", line 97, in _run_module_code
_run_code(code, mod_globals, init_globals,
File "C:\Program Files\Python39\lib\runpy.py", line 87, in _run_code
exec(code, run_globals)
File "c:\Users\Ali.Khankan\Desktop\gym-mtsim\ali_test.py", line 16, in
env = MtEnv(
File "c:\Users\Ali.Khankan\Desktop\gym-mtsim\gym_mtsim\envs\mt_env.py", line 63, in init
self.multiprocessing_pool = Pool(multiprocessing_processes) if multiprocessing_processes else None
File "C:\Users\Ali.Khankan\AppData\Roaming\Python\Python39\site-packages\pathos\multiprocessing.py", line 111, in init
self._serve()
File "C:\Users\Ali.Khankan\AppData\Roaming\Python\Python39\site-packages\pathos\multiprocessing.py", line 123, in _serve
_pool = Pool(nodes)
File "C:\Users\Ali.Khankan\AppData\Roaming\Python\Python39\site-packages\multiprocess\pool.py", line 212, in init
self._repopulate_pool()
File "C:\Users\Ali.Khankan\AppData\Roaming\Python\Python39\site-packages\multiprocess\pool.py", line 303, in _repopulate_pool
return self._repopulate_pool_static(self._ctx, self.Process,
File "C:\Users\Ali.Khankan\AppData\Roaming\Python\Python39\site-packages\multiprocess\pool.py", line 326, in _repopulate_pool_static
w.start()
File "C:\Users\Ali.Khankan\AppData\Roaming\Python\Python39\site-packages\multiprocess\process.py", line 121, in start
self._popen = self._Popen(self)
File "C:\Users\Ali.Khankan\AppData\Roaming\Python\Python39\site-packages\multiprocess\context.py", line 327, in _Popen
return Popen(process_obj)
File "C:\Users\Ali.Khankan\AppData\Roaming\Python\Python39\site-packages\multiprocess\popen_spawn_win32.py", line 45, in init
prep_data = spawn.get_preparation_data(process_obj._name)
File "C:\Users\Ali.Khankan\AppData\Roaming\Python\Python39\site-packages\multiprocess\spawn.py", line 154, in get_preparation_data
_check_not_importing_main()
File "C:\Users\Ali.Khankan\AppData\Roaming\Python\Python39\site-packages\multiprocess\spawn.py", line 134, in _check_not_importing_main
raise RuntimeError('''
RuntimeError:
An attempt has been made to start a new process before the
current process has finished its bootstrapping phase.

    This probably means that you are not using fork to start your
    child processes and you have forgotten to use the proper idiom
    in the main module:

        if __name__ == '__main__':
            freeze_support()
            ...

    The "freeze_support()" line can be omitted if the program
    is not going to be frozen to produce an executable.

setting multiprocessing_processes = 0 solved the problem

[yglpyn8888]

i met this problem before and i comment out this directly ( # multiprocessing_processes=2)

[sadimoodi]

@yglpyn8888 i did this too, but then whats the point of using multi processing?

[yglpyn8888]

@yglpyn8888 i did this too, but then whats the point of using multi processing?

This may have to be answered by the author. At this stage, I just want to run through the environment and test some questions that I care about.

[AminHP]

You should put your code inside this if __name__ == '__main__': statement if you are using multiprocessing. It's required because of the concept of forking in the OS kernel in order to handle the child processes, but we don't have to worry about that. Just put your code inside the mentioned if statement.