SubprocVecEnv not working

I’m trying to use SubprocVecEnv to initialize multiple instances of one environment to use in ACKTR and A2C, however, there seem to be problems with SubprocVecEnv. Following this code, the following happens:

def make_env():
    env = gym.make('Test-v0')
    return env

env = gym.make('Test-v0') #Works, env initialization message is printed
env = make_env() #Works, env initialization message is printed
env = SubprocVecEnv([make_env]) #Doesn't work, code gets stuck

Meaning, env creation through the function works fine, the same goes for manual creation, however, when SubprocVecEnv is called the code gets stuck, nothing seems to happen and it doesn’t stop running, nor does the environment get created.

I tried calling manually env = SubprocVecEnv([make_env]) and it yields a strange error:

env = SubprocVecEnv([make_env]) Traceback (most recent call last):

File “<ipython-input-8-427e992f56b1>”, line 1, in <module> env = SubprocVecEnv([make_env])

File “c:\users\x\baselines\baselines\common\vec_env\subproc_vec_env.py”, line 58, in init observation_space, action_space = self.remotes[0].recv()

File “D:\Programs\Anaconda3\lib\multiprocessing\connection.py”, line 250, in recv buf = self._recv_bytes()

File “D:\Programs\Anaconda3\lib\multiprocessing\connection.py”, line 321, in _recv_bytes raise EOFError

EOFError

[abhiskk]

It does use SubprocVecEnv, I just make a dummy call to custom_atari_env before making a call to the original make_atari_env.

env = custom_atari_env('BreakoutNoFrameskip-v4', num_env=4, seed=42)
env = make_atari_env('PongNoFrameskip-v4', num_env=4, seed=42)

The call to custom_atari_env I think sets something up in the background and the make_atari_env does not throw an error after that.

[pzhokhov]

@Coronon could you provide the code you are running and error stacktrace? The baselines code has changed quite a bit since the issue was opened; it would be helpful to have a recent stacktrace.