MultiStepActorWrapper

class torchrl.modules.tensordict_module.MultiStepActorWrapper(*args, **kwargs)

一個多動作 actor 的封裝器。

此類允許在環境中執行宏（macros）。actor 的動作(action)條目必須包含一個額外的時間維度才能被使用。它必須緊鄰輸入 tensordict 的最後一個維度（即在 tensordict.ndim 處）。

如果未提供動作(action)條目鍵，將使用簡單的啟發式方法從 actor 自動檢索（任何以字串 "action" 結尾的巢狀鍵）。

輸入 tensordict 中還必須存在一個 "is_init" 條目，用於跟蹤當前收集應何時因遇到“完成”狀態而中斷。與 action_keys 不同，此鍵必須是唯一的。

引數：

• actor (TensorDictModuleBase) – 一個 actor。

• n_steps (int) – actor 一次輸出的動作數量（前瞻視窗）。

關鍵字引數：

• action_keys (list of NestedKeys, 可選) – 來自環境的動作(action)鍵。可以從 env.action_keys 中檢索。預設為 actor 的所有以字串 "action" 結尾的 out_keys。

• init_key (NestedKey, 可選) – 指示環境何時經歷重置的條目鍵。預設為 "is_init"，這是來自 InitTracker 變換的 out_key。

示例

>>> import torch.nn
>>> from torchrl.modules.tensordict_module.actors import MultiStepActorWrapper, Actor
>>> from torchrl.envs import CatFrames, GymEnv, TransformedEnv, SerialEnv, InitTracker, Compose
>>> from tensordict.nn import TensorDictSequential as Seq, TensorDictModule as Mod
>>>
>>> time_steps = 6
>>> n_obs = 4
>>> n_action = 2
>>> batch = 5
>>>
>>> # Transforms a CatFrames in a stack of frames
>>> def reshape_cat(data: torch.Tensor):
...     return data.unflatten(-1, (time_steps, n_obs))
>>> # an actor that reads `time_steps` frames and outputs one action per frame
>>> # (actions are conditioned on the observation of `time_steps` in the past)
>>> actor_base = Seq(
...     Mod(reshape_cat, in_keys=["obs_cat"], out_keys=["obs_cat_reshape"]),
...     Mod(torch.nn.Linear(n_obs, n_action), in_keys=["obs_cat_reshape"], out_keys=["action"])
... )
>>> # Wrap the actor to dispatch the actions
>>> actor = MultiStepActorWrapper(actor_base, n_steps=time_steps)
>>>
>>> env = TransformedEnv(
...     SerialEnv(batch, lambda: GymEnv("CartPole-v1")),
...     Compose(
...         InitTracker(),
...         CatFrames(N=time_steps, in_keys=["observation"], out_keys=["obs_cat"], dim=-1)
...     )
... )
>>>
>>> print(env.rollout(100, policy=actor, break_when_any_done=False))
TensorDict(
    fields={
        action: Tensor(shape=torch.Size([5, 100, 2]), device=cpu, dtype=torch.float32, is_shared=False),
        action_orig: Tensor(shape=torch.Size([5, 100, 6, 2]), device=cpu, dtype=torch.float32, is_shared=False),
        counter: Tensor(shape=torch.Size([5, 100, 1]), device=cpu, dtype=torch.int32, is_shared=False),
        done: Tensor(shape=torch.Size([5, 100, 1]), device=cpu, dtype=torch.bool, is_shared=False),
        is_init: Tensor(shape=torch.Size([5, 100, 1]), device=cpu, dtype=torch.bool, is_shared=False),
        next: TensorDict(
            fields={
                done: Tensor(shape=torch.Size([5, 100, 1]), device=cpu, dtype=torch.bool, is_shared=False),
                is_init: Tensor(shape=torch.Size([5, 100, 1]), device=cpu, dtype=torch.bool, is_shared=False),
                obs_cat: Tensor(shape=torch.Size([5, 100, 24]), device=cpu, dtype=torch.float32, is_shared=False),
                observation: Tensor(shape=torch.Size([5, 100, 4]), device=cpu, dtype=torch.float32, is_shared=False),
                reward: Tensor(shape=torch.Size([5, 100, 1]), device=cpu, dtype=torch.float32, is_shared=False),
                terminated: Tensor(shape=torch.Size([5, 100, 1]), device=cpu, dtype=torch.bool, is_shared=False),
                truncated: Tensor(shape=torch.Size([5, 100, 1]), device=cpu, dtype=torch.bool, is_shared=False)},
            batch_size=torch.Size([5, 100]),
            device=cpu,
            is_shared=False),
        obs_cat: Tensor(shape=torch.Size([5, 100, 24]), device=cpu, dtype=torch.float32, is_shared=False),
        observation: Tensor(shape=torch.Size([5, 100, 4]), device=cpu, dtype=torch.float32, is_shared=False),
        terminated: Tensor(shape=torch.Size([5, 100, 1]), device=cpu, dtype=torch.bool, is_shared=False),
        truncated: Tensor(shape=torch.Size([5, 100, 1]), device=cpu, dtype=torch.bool, is_shared=False)},
    batch_size=torch.Size([5, 100]),
    device=cpu,
    is_shared=False)

forward(tensordict: TensorDictBase) → TensorDictBase

定義每次呼叫時執行的計算。

應由所有子類重寫。

注意

儘管前向傳播（forward pass）的實現需要在該函式內定義，但之後應呼叫 Module 例項而非此函式，因為前者會負責執行註冊的 hook，而後者會靜默忽略它們。

property init_key: NestedKey

批處理中給定元素的初始步驟指示器。