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| """Wrapper that autoreset environments when `terminated=True` or `truncated=True`.""" | |
| import gym | |
| class AutoResetWrapper(gym.Wrapper): | |
| """A class for providing an automatic reset functionality for gym environments when calling :meth:`self.step`. | |
| When calling step causes :meth:`Env.step` to return `terminated=True` or `truncated=True`, :meth:`Env.reset` is called, | |
| and the return format of :meth:`self.step` is as follows: ``(new_obs, final_reward, final_terminated, final_truncated, info)`` | |
| with new step API and ``(new_obs, final_reward, final_done, info)`` with the old step API. | |
| - ``new_obs`` is the first observation after calling :meth:`self.env.reset` | |
| - ``final_reward`` is the reward after calling :meth:`self.env.step`, prior to calling :meth:`self.env.reset`. | |
| - ``final_terminated`` is the terminated value before calling :meth:`self.env.reset`. | |
| - ``final_truncated`` is the truncated value before calling :meth:`self.env.reset`. Both `final_terminated` and `final_truncated` cannot be False. | |
| - ``info`` is a dict containing all the keys from the info dict returned by the call to :meth:`self.env.reset`, | |
| with an additional key "final_observation" containing the observation returned by the last call to :meth:`self.env.step` | |
| and "final_info" containing the info dict returned by the last call to :meth:`self.env.step`. | |
| Warning: When using this wrapper to collect rollouts, note that when :meth:`Env.step` returns `terminated` or `truncated`, a | |
| new observation from after calling :meth:`Env.reset` is returned by :meth:`Env.step` alongside the | |
| final reward, terminated and truncated state from the previous episode. | |
| If you need the final state from the previous episode, you need to retrieve it via the | |
| "final_observation" key in the info dict. | |
| Make sure you know what you're doing if you use this wrapper! | |
| """ | |
| def __init__(self, env: gym.Env): | |
| """A class for providing an automatic reset functionality for gym environments when calling :meth:`self.step`. | |
| Args: | |
| env (gym.Env): The environment to apply the wrapper | |
| """ | |
| super().__init__(env) | |
| def step(self, action): | |
| """Steps through the environment with action and resets the environment if a terminated or truncated signal is encountered. | |
| Args: | |
| action: The action to take | |
| Returns: | |
| The autoreset environment :meth:`step` | |
| """ | |
| obs, reward, terminated, truncated, info = self.env.step(action) | |
| if terminated or truncated: | |
| new_obs, new_info = self.env.reset() | |
| assert ( | |
| "final_observation" not in new_info | |
| ), 'info dict cannot contain key "final_observation" ' | |
| assert ( | |
| "final_info" not in new_info | |
| ), 'info dict cannot contain key "final_info" ' | |
| new_info["final_observation"] = obs | |
| new_info["final_info"] = info | |
| obs = new_obs | |
| info = new_info | |
| return obs, reward, terminated, truncated, info | |