Pass action into env.step for gym env

[RupaliBhati]

The action should be a tuple with the joint action of the primary and secondary agents in index format. I tried the following code:

mdp = OvercookedGridworld.from_layout_name("cramped_room")
base_env = OvercookedEnv.from_mdp(mdp, horizon=500)
env = gym.make("Overcooked-v0",base_env = base_env, featurize_fn =base_env.featurize_state_mdp)
env.reset()
env.step((0,0))

I got the following error:

AttributeError Traceback (most recent call last)
Cell In[5], line 1
----> 1 env.step((0,0))

File ~/.pyenv/versions/3.9.1/envs/myvenv/lib/python3.9/site-packages/gym/wrappers/order_enforcing.py:37, in OrderEnforcing.step(self, action)
35 if not self._has_reset:
36 raise ResetNeeded("Cannot call env.step() before calling env.reset()")
---> 37 return self.env.step(action)

File ~/.pyenv/versions/3.9.1/envs/myvenv/lib/python3.9/site-packages/gym/wrappers/step_api_compatibility.py:52, in StepAPICompatibility.step(self, action)
43 def step(self, action):
44 """Steps through the environment, returning 5 or 4 items depending on new_step_api.
45
46 Args:
(...)
50 (observation, reward, terminated, truncated, info) or (observation, reward, done, info)
51 """
---> 52 step_returns = self.env.step(action)
53 if self.new_step_api:
54 return step_to_new_api(step_returns)

File ~/.pyenv/versions/3.9.1/envs/myvenv/lib/python3.9/site-packages/gym/wrappers/env_checker.py:39, in PassiveEnvChecker.step(self, action)
37 return env_step_passive_checker(self.env, action)
38 else:
...
-> 1851 for obj in state.objects.values():
1852 if obj.position in counters_considered:
1853 counter_objects_dict[obj.name].append(obj.position)

AttributeError: 'OvercookedGridworld' object has no attribute 'objects'

I tried many alternatives but none of them worked. Can you share an example of what I should pass in the env.step function?

[jyan1999]

Hi,

Thanks for bringing this issue up. I looked into this briefly and it looks like it is a hidden bug in the code. There is a quick one-line fix for this issue. If you go to overcooked_env.py, you just need to change

ob_p0, ob_p1 = self.featurize_fn(self.mdp, next_state)

to

ob_p0, ob_p1 = self.featurize_fn(next_state)

I apologize for this issue and will push a fix asap. The gym environment is not very well maintained and is mostly there for reference. If you run into any other problems please let me know!

[RupaliBhati]

Thanks a lot @jyan1999!