test/mocking_classes.py

# Copyright (c) Meta Platforms, Inc. and affiliates.
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
from typing import Optional

import torch
import torch.nn as nn
from tensordict.tensordict import TensorDict, TensorDictBase
from tensordict.utils import expand_right, NestedKey

from torchrl.data.tensor_specs import (
    BinaryDiscreteTensorSpec,
    BoundedTensorSpec,
    CompositeSpec,
    DiscreteTensorSpec,
    MultiOneHotDiscreteTensorSpec,
    OneHotDiscreteTensorSpec,
    TensorSpec,
    UnboundedContinuousTensorSpec,
)
from torchrl.data.utils import consolidate_spec
from torchrl.envs.common import EnvBase
from torchrl.envs.model_based.common import ModelBasedEnvBase

spec_dict = {
    "bounded": BoundedTensorSpec,
    "one_hot": OneHotDiscreteTensorSpec,
    "categorical": DiscreteTensorSpec,
    "unbounded": UnboundedContinuousTensorSpec,
    "binary": BinaryDiscreteTensorSpec,
    "mult_one_hot": MultiOneHotDiscreteTensorSpec,
    "composite": CompositeSpec,
}

default_spec_kwargs = {
    OneHotDiscreteTensorSpec: {"n": 7},
    DiscreteTensorSpec: {"n": 7},
    BoundedTensorSpec: {"minimum": -torch.ones(4), "maximum": torch.ones(4)},
    UnboundedContinuousTensorSpec: {
        "shape": [
            7,
        ]
    },
    BinaryDiscreteTensorSpec: {"n": 7},
    MultiOneHotDiscreteTensorSpec: {"nvec": [7, 3, 5]},
    CompositeSpec: {},
}


def make_spec(spec_str):
    target_class = spec_dict[spec_str]
    return target_class(**default_spec_kwargs[target_class])


class _MockEnv(EnvBase):
    @classmethod
    def __new__(
        cls,
        *args,
        **kwargs,
    ):
        for key, item in list(cls._output_spec["full_observation_spec"].items()):
            cls._output_spec["full_observation_spec"][key] = item.to(
                torch.get_default_dtype()
            )
        reward_spec = cls._output_spec["full_reward_spec"]
        if isinstance(reward_spec, CompositeSpec):
            reward_spec = CompositeSpec(
                {
                    key: item.to(torch.get_default_dtype())
                    for key, item in reward_spec.items(True, True)
                },
                shape=reward_spec.shape,
                device=reward_spec.device,
            )
        else:
            reward_spec = reward_spec.to(torch.get_default_dtype())
        cls._output_spec["full_reward_spec"] = reward_spec
        if not isinstance(cls._output_spec["full_reward_spec"], CompositeSpec):
            cls._output_spec["full_reward_spec"] = CompositeSpec(
                reward=cls._output_spec["full_reward_spec"],
                shape=cls._output_spec["full_reward_spec"].shape[:-1],
            )
        if not isinstance(cls._output_spec["full_done_spec"], CompositeSpec):
            cls._output_spec["full_done_spec"] = CompositeSpec(
                done=cls._output_spec["full_done_spec"].clone(),
                terminated=cls._output_spec["full_done_spec"].clone(),
                shape=cls._output_spec["full_done_spec"].shape[:-1],
            )
        if not isinstance(cls._input_spec["full_action_spec"], CompositeSpec):
            cls._input_spec["full_action_spec"] = CompositeSpec(
                action=cls._input_spec["full_action_spec"],
                shape=cls._input_spec["full_action_spec"].shape[:-1],
            )
        return super().__new__(cls, *args, **kwargs)

    def __init__(
        self,
        *args,
        seed: int = 100,
        **kwargs,
    ):
        super().__init__(
            device=kwargs.pop("device", "cpu"),
            dtype=torch.get_default_dtype(),
        )
        self.set_seed(seed)
        self.is_closed = False

    @property
    def maxstep(self):
        return 100

    def _set_seed(self, seed: Optional[int]):
        self.seed = seed
        self.counter = seed % 17  # make counter a small number

    def custom_fun(self):
        return 0

    custom_attr = 1

    @property
    def custom_prop(self):
        return 2

    @property
    def custom_td(self):
        return TensorDict({"a": torch.zeros(3)}, [])


class MockSerialEnv(EnvBase):
    """A simple counting env that is reset after a predifined max number of steps."""

    @classmethod
    def __new__(
        cls,
        *args,
        observation_spec=None,
        action_spec=None,
        state_spec=None,
        reward_spec=None,
        done_spec=None,
        **kwargs,
    ):
        batch_size = kwargs.setdefault("batch_size", torch.Size([]))
        if action_spec is None:
            action_spec = UnboundedContinuousTensorSpec(
                (
                    *batch_size,
                    1,
                )
            )
        if observation_spec is None:
            observation_spec = CompositeSpec(
                observation=UnboundedContinuousTensorSpec(
                    (
                        *batch_size,
                        1,
                    )
                ),
                shape=batch_size,
            )
        if reward_spec is None:
            reward_spec = UnboundedContinuousTensorSpec(
                (
                    *batch_size,
                    1,
                )
            )
        if done_spec is None:
            done_spec = DiscreteTensorSpec(2, dtype=torch.bool, shape=(*batch_size, 1))
        if state_spec is None:
            state_spec = CompositeSpec(shape=batch_size)
        input_spec = CompositeSpec(
            full_action_spec=action_spec, full_state_spec=state_spec, shape=batch_size
        )
        cls._output_spec = CompositeSpec(shape=batch_size)
        cls._output_spec["full_reward_spec"] = reward_spec
        cls._output_spec["full_done_spec"] = done_spec
        cls._output_spec["full_observation_spec"] = observation_spec
        cls._input_spec = input_spec

        if not isinstance(cls._output_spec["full_reward_spec"], CompositeSpec):
            cls._output_spec["full_reward_spec"] = CompositeSpec(
                reward=cls._output_spec["full_reward_spec"], shape=batch_size
            )
        if not isinstance(cls._output_spec["full_done_spec"], CompositeSpec):
            cls._output_spec["full_done_spec"] = CompositeSpec(
                done=cls._output_spec["full_done_spec"], shape=batch_size
            )
        if not isinstance(cls._input_spec["full_action_spec"], CompositeSpec):
            cls._input_spec["full_action_spec"] = CompositeSpec(
                action=cls._input_spec["full_action_spec"], shape=batch_size
            )
        return super().__new__(*args, **kwargs)

    def __init__(self, device="cpu"):
        super(MockSerialEnv, self).__init__(device=device)
        self.is_closed = False

    def _set_seed(self, seed: Optional[int]):
        assert seed >= 1
        self.seed = seed
        self.counter = seed % 17  # make counter a small number
        self.max_val = max(self.counter + 100, self.counter * 2)

    def _step(self, tensordict):
        self.counter += 1
        n = torch.tensor(
            [self.counter], device=self.device, dtype=torch.get_default_dtype()
        )
        done = self.counter >= self.max_val
        done = torch.tensor([done], dtype=torch.bool, device=self.device)
        return TensorDict(
            {
                "reward": n,
                "done": done,
                "terminated": done.clone(),
                "observation": n.clone(),
            },
            batch_size=[],
        )

    def _reset(self, tensordict: TensorDictBase = None, **kwargs) -> TensorDictBase:
        self.max_val = max(self.counter + 100, self.counter * 2)

        n = torch.tensor(
            [self.counter], device=self.device, dtype=torch.get_default_dtype()
        )
        done = self.counter >= self.max_val
        done = torch.tensor([done], dtype=torch.bool, device=self.device)
        return TensorDict(
            {"done": done, "terminated": done.clone(), "observation": n}, []
        )

    def rand_step(self, tensordict: Optional[TensorDictBase] = None) -> TensorDictBase:
        return self.step(tensordict)


class MockBatchedLockedEnv(EnvBase):
    """Mocks an env whose batch_size defines the size of the output tensordict"""

    @classmethod
    def __new__(
        cls,
        *args,
        observation_spec=None,
        action_spec=None,
        state_spec=None,
        reward_spec=None,
        done_spec=None,
        **kwargs,
    ):
        batch_size = kwargs.setdefault("batch_size", torch.Size([]))
        if action_spec is None:
            action_spec = UnboundedContinuousTensorSpec(
                (
                    *batch_size,
                    1,
                )
            )
        if state_spec is None:
            state_spec = CompositeSpec(
                observation=UnboundedContinuousTensorSpec(
                    (
                        *batch_size,
                        1,
                    )
                ),
                shape=batch_size,
            )
        if observation_spec is None:
            observation_spec = CompositeSpec(
                observation=UnboundedContinuousTensorSpec(
                    (
                        *batch_size,
                        1,
                    )
                ),
                shape=batch_size,
            )
        if reward_spec is None:
            reward_spec = UnboundedContinuousTensorSpec(
                (
                    *batch_size,
                    1,
                )
            )
        if done_spec is None:
            done_spec = DiscreteTensorSpec(2, dtype=torch.bool, shape=(*batch_size, 1))
        cls._output_spec = CompositeSpec(shape=batch_size)
        cls._output_spec["full_reward_spec"] = reward_spec
        cls._output_spec["full_done_spec"] = done_spec
        cls._output_spec["full_observation_spec"] = observation_spec
        cls._input_spec = CompositeSpec(
            full_action_spec=action_spec,
            full_state_spec=state_spec,
            shape=batch_size,
        )
        if not isinstance(cls._output_spec["full_reward_spec"], CompositeSpec):
            cls._output_spec["full_reward_spec"] = CompositeSpec(
                reward=cls._output_spec["full_reward_spec"], shape=batch_size
            )
        if not isinstance(cls._output_spec["full_done_spec"], CompositeSpec):
            cls._output_spec["full_done_spec"] = CompositeSpec(
                done=cls._output_spec["full_done_spec"], shape=batch_size
            )
        if not isinstance(cls._input_spec["full_action_spec"], CompositeSpec):
            cls._input_spec["full_action_spec"] = CompositeSpec(
                action=cls._input_spec["full_action_spec"], shape=batch_size
            )
        return super().__new__(cls, *args, **kwargs)

    def __init__(self, device="cpu", batch_size=None):
        super(MockBatchedLockedEnv, self).__init__(device=device, batch_size=batch_size)
        self.counter = 0

    rand_step = MockSerialEnv.rand_step

    def _set_seed(self, seed: Optional[int]):
        assert seed >= 1
        self.seed = seed
        self.counter = seed % 17  # make counter a small number
        self.max_val = max(self.counter + 100, self.counter * 2)

    def _step(self, tensordict):
        if len(self.batch_size):
            leading_batch_size = (
                tensordict.shape[: -len(self.batch_size)]
                if tensordict is not None
                else []
            )
        else:
            leading_batch_size = tensordict.shape if tensordict is not None else []
        self.counter += 1
        # We use tensordict.batch_size instead of self.batch_size since this method will also be used by MockBatchedUnLockedEnv
        n = (
            torch.full(
                [*leading_batch_size, *self.observation_spec["observation"].shape],
                self.counter,
            )
            .to(self.device)
            .to(torch.get_default_dtype())
        )
        done = self.counter >= self.max_val
        done = torch.full(
            (*leading_batch_size, *self.batch_size, 1),
            done,
            dtype=torch.bool,
            device=self.device,
        )
        return TensorDict(
            {"reward": n, "done": done, "terminated": done.clone(), "observation": n},
            batch_size=tensordict.batch_size,
            device=self.device,
        )

    def _reset(self, tensordict: TensorDictBase, **kwargs) -> TensorDictBase:
        self.max_val = max(self.counter + 100, self.counter * 2)
        batch_size = self.batch_size
        if len(batch_size):
            leading_batch_size = (
                tensordict.shape[: -len(self.batch_size)]
                if tensordict is not None
                else []
            )
        else:
            leading_batch_size = tensordict.shape if tensordict is not None else []

        n = (
            torch.full(
                [*leading_batch_size, *self.observation_spec["observation"].shape],
                self.counter,
            )
            .to(self.device)
            .to(torch.get_default_dtype())
        )
        done = self.counter >= self.max_val
        done = torch.full(
            (*leading_batch_size, *batch_size, 1),
            done,
            dtype=torch.bool,
            device=self.device,
        )
        return TensorDict(
            {"done": done, "terminated": done.clone(), "observation": n},
            [
                *leading_batch_size,
                *batch_size,
            ],
            device=self.device,
        )


class MockBatchedUnLockedEnv(MockBatchedLockedEnv):
    """Mocks an env whose batch_size does not define the size of the output tensordict.

    The size of the output tensordict is defined by the input tensordict itself.

    """

    def __init__(self, device="cpu", batch_size=None):
        super(MockBatchedUnLockedEnv, self).__init__(
            batch_size=batch_size, device=device
        )

    @classmethod
    def __new__(cls, *args, **kwargs):
        return super().__new__(cls, *args, _batch_locked=False, **kwargs)


class DiscreteActionVecMockEnv(_MockEnv):
    @classmethod
    def __new__(
        cls,
        *args,
        observation_spec=None,
        action_spec=None,
        state_spec=None,
        reward_spec=None,
        done_spec=None,
        from_pixels=False,
        categorical_action_encoding=False,
        **kwargs,
    ):
        batch_size = kwargs.setdefault("batch_size", torch.Size([]))
        size = cls.size = 7
        if observation_spec is None:
            cls.out_key = "observation"
            observation_spec = CompositeSpec(
                observation=UnboundedContinuousTensorSpec(
                    shape=torch.Size([*batch_size, size])
                ),
                observation_orig=UnboundedContinuousTensorSpec(
                    shape=torch.Size([*batch_size, size])
                ),
                shape=batch_size,
            )
        if action_spec is None:
            if categorical_action_encoding:
                action_spec_cls = DiscreteTensorSpec
                action_spec = action_spec_cls(n=7, shape=batch_size)
            else:
                action_spec_cls = OneHotDiscreteTensorSpec
                action_spec = action_spec_cls(n=7, shape=(*batch_size, 7))
        if reward_spec is None:
            reward_spec = CompositeSpec(
                reward=UnboundedContinuousTensorSpec(shape=(1,))
            )
        if done_spec is None:
            done_spec = CompositeSpec(
                terminated=DiscreteTensorSpec(
                    2, dtype=torch.bool, shape=(*batch_size, 1)
                )
            )

        if state_spec is None:
            cls._out_key = "observation_orig"
            state_spec = CompositeSpec(
                {
                    cls._out_key: observation_spec["observation"],
                },
                shape=batch_size,
            )
        cls._output_spec = CompositeSpec(shape=batch_size)
        cls._output_spec["full_reward_spec"] = reward_spec
        cls._output_spec["full_done_spec"] = done_spec
        cls._output_spec["full_observation_spec"] = observation_spec
        cls._input_spec = CompositeSpec(
            full_action_spec=action_spec,
            full_state_spec=state_spec,
            shape=batch_size,
        )
        cls.from_pixels = from_pixels
        cls.categorical_action_encoding = categorical_action_encoding
        return super().__new__(*args, **kwargs)

    def _get_in_obs(self, obs):
        return obs

    def _get_out_obs(self, obs):
        return obs

    def _reset(self, tensordict: TensorDictBase = None) -> TensorDictBase:
        self.counter += 1
        state = torch.zeros(self.size) + self.counter
        if tensordict is None:
            tensordict = TensorDict({}, self.batch_size, device=self.device)
        tensordict = tensordict.select().set(self.out_key, self._get_out_obs(state))
        tensordict = tensordict.set(self._out_key, self._get_out_obs(state))
        tensordict.set("done", torch.zeros(*tensordict.shape, 1, dtype=torch.bool))
        tensordict.set(
            "terminated", torch.zeros(*tensordict.shape, 1, dtype=torch.bool)
        )
        return tensordict

    def _step(
        self,
        tensordict: TensorDictBase,
    ) -> TensorDictBase:
        tensordict = tensordict.to(self.device)
        a = tensordict.get("action")

        if not self.categorical_action_encoding:
            assert (a.sum(-1) == 1).all()

        obs = self._get_in_obs(tensordict.get(self._out_key)) + a / self.maxstep
        tensordict = tensordict.select()  # empty tensordict

        tensordict.set(self.out_key, self._get_out_obs(obs))
        tensordict.set(self._out_key, self._get_out_obs(obs))

        done = torch.isclose(obs, torch.ones_like(obs) * (self.counter + 1))
        reward = done.any(-1).unsqueeze(-1)

        # set done to False
        done = torch.zeros_like(done).all(-1).unsqueeze(-1)
        tensordict.set("reward", reward.to(torch.get_default_dtype()))
        tensordict.set("done", done)
        tensordict.set("terminated", done.clone())
        return tensordict


class ContinuousActionVecMockEnv(_MockEnv):
    @classmethod
    def __new__(
        cls,
        *args,
        observation_spec=None,
        action_spec=None,
        state_spec=None,
        reward_spec=None,
        done_spec=None,
        from_pixels=False,
        **kwargs,
    ):
        batch_size = kwargs.setdefault("batch_size", torch.Size([]))
        size = cls.size = 7
        if observation_spec is None:
            cls.out_key = "observation"
            observation_spec = CompositeSpec(
                observation=UnboundedContinuousTensorSpec(
                    shape=torch.Size([*batch_size, size])
                ),
                observation_orig=UnboundedContinuousTensorSpec(
                    shape=torch.Size([*batch_size, size])
                ),
                shape=batch_size,
            )
        if action_spec is None:
            action_spec = BoundedTensorSpec(
                -1,
                1,
                (
                    *batch_size,
                    7,
                ),
            )
        if reward_spec is None:
            reward_spec = UnboundedContinuousTensorSpec(shape=(*batch_size, 1))
        if done_spec is None:
            done_spec = DiscreteTensorSpec(2, dtype=torch.bool, shape=(*batch_size, 1))

        if state_spec is None:
            cls._out_key = "observation_orig"
            state_spec = CompositeSpec(
                {
                    cls._out_key: observation_spec["observation"],
                },
                shape=batch_size,
            )
        cls._output_spec = CompositeSpec(shape=batch_size)
        cls._output_spec["full_reward_spec"] = reward_spec
        cls._output_spec["full_done_spec"] = done_spec
        cls._output_spec["full_observation_spec"] = observation_spec
        cls._input_spec = CompositeSpec(
            full_action_spec=action_spec,
            full_state_spec=state_spec,
            shape=batch_size,
        )
        cls.from_pixels = from_pixels
        return super().__new__(cls, *args, **kwargs)

    def _get_in_obs(self, obs):
        return obs

    def _get_out_obs(self, obs):
        return obs

    def _reset(self, tensordict: TensorDictBase) -> TensorDictBase:
        self.counter += 1
        self.step_count = 0
        # state = torch.zeros(self.size) + self.counter
        if tensordict is None:
            tensordict = TensorDict({}, self.batch_size, device=self.device)
        tensordict = tensordict.select()
        tensordict.update(self.observation_spec.rand())
        # tensordict.set("next_" + self.out_key, self._get_out_obs(state))
        # tensordict.set("next_" + self._out_key, self._get_out_obs(state))
        tensordict.set("done", torch.zeros(*tensordict.shape, 1, dtype=torch.bool))
        tensordict.set(
            "terminated", torch.zeros(*tensordict.shape, 1, dtype=torch.bool)
        )
        return tensordict

    def _step(
        self,
        tensordict: TensorDictBase,
    ) -> TensorDictBase:
        self.step_count += 1
        tensordict = tensordict.to(self.device)
        a = tensordict.get("action")

        obs = self._obs_step(self._get_in_obs(tensordict.get(self._out_key)), a)
        tensordict = tensordict.select()  # empty tensordict

        tensordict.set(self.out_key, self._get_out_obs(obs))
        tensordict.set(self._out_key, self._get_out_obs(obs))

        done = torch.isclose(obs, torch.ones_like(obs) * (self.counter + 1))
        while done.shape != tensordict.shape:
            done = done.any(-1)
        done = reward = done.unsqueeze(-1)
        tensordict.set("reward", reward.to(torch.get_default_dtype()))
        tensordict.set("done", done)
        tensordict.set("terminated", done)
        return tensordict

    def _obs_step(self, obs, a):
        return obs + a / self.maxstep


class DiscreteActionVecPolicy:
    in_keys = ["observation"]
    out_keys = ["action"]

    def _get_in_obs(self, tensordict):
        obs = tensordict.get(*self.in_keys)
        return obs

    def __call__(self, tensordict):
        obs = self._get_in_obs(tensordict)
        max_obs = (obs == obs.max(dim=-1, keepdim=True)[0]).cumsum(-1).argmax(-1)
        k = tensordict.get(*self.in_keys).shape[-1]
        max_obs = (max_obs + 1) % k
        action = torch.nn.functional.one_hot(max_obs, k)
        tensordict.set(*self.out_keys, action)
        return tensordict


class DiscreteActionConvMockEnv(DiscreteActionVecMockEnv):
    @classmethod
    def __new__(
        cls,
        *args,
        observation_spec=None,
        action_spec=None,
        state_spec=None,
        reward_spec=None,
        done_spec=None,
        from_pixels=True,
        **kwargs,
    ):
        batch_size = kwargs.setdefault("batch_size", torch.Size([]))
        if observation_spec is None:
            cls.out_key = "pixels"
            observation_spec = CompositeSpec(
                pixels=UnboundedContinuousTensorSpec(
                    shape=torch.Size([*batch_size, 1, 7, 7])
                ),
                pixels_orig=UnboundedContinuousTensorSpec(
                    shape=torch.Size([*batch_size, 1, 7, 7])
                ),
                shape=batch_size,
            )
        if action_spec is None:
            action_spec = OneHotDiscreteTensorSpec(7, shape=(*batch_size, 7))
        if reward_spec is None:
            reward_spec = UnboundedContinuousTensorSpec(shape=(*batch_size, 1))
        if done_spec is None:
            done_spec = DiscreteTensorSpec(2, dtype=torch.bool, shape=(*batch_size, 1))

        if state_spec is None:
            cls._out_key = "pixels_orig"
            state_spec = CompositeSpec(
                {
                    cls._out_key: observation_spec["pixels_orig"].clone(),
                },
                shape=batch_size,
            )
        return super().__new__(
            *args,
            observation_spec=observation_spec,
            action_spec=action_spec,
            reward_spec=reward_spec,
            state_spec=state_spec,
            from_pixels=from_pixels,
            done_spec=done_spec,
            **kwargs,
        )

    def _get_out_obs(self, obs):
        obs = torch.diag_embed(obs, 0, -2, -1).unsqueeze(0)
        return obs

    def _get_in_obs(self, obs):
        return obs.diagonal(0, -1, -2).squeeze()


class DiscreteActionConvMockEnvNumpy(DiscreteActionConvMockEnv):
    @classmethod
    def __new__(
        cls,
        *args,
        observation_spec=None,
        action_spec=None,
        state_spec=None,
        reward_spec=None,
        done_spec=None,
        from_pixels=True,
        categorical_action_encoding=False,
        **kwargs,
    ):
        batch_size = kwargs.setdefault("batch_size", torch.Size([]))
        if observation_spec is None:
            cls.out_key = "pixels"
            observation_spec = CompositeSpec(
                pixels=UnboundedContinuousTensorSpec(
                    shape=torch.Size([*batch_size, 7, 7, 3])
                ),
                pixels_orig=UnboundedContinuousTensorSpec(
                    shape=torch.Size([*batch_size, 7, 7, 3])
                ),
                shape=batch_size,
            )
        if action_spec is None:
            action_spec_cls = (
                DiscreteTensorSpec
                if categorical_action_encoding
                else OneHotDiscreteTensorSpec
            )
            action_spec = action_spec_cls(7, shape=(*batch_size, 7))
        if state_spec is None:
            cls._out_key = "pixels_orig"
            state_spec = CompositeSpec(
                {
                    cls._out_key: observation_spec["pixels_orig"],
                },
                shape=batch_size,
            )

        return super().__new__(
            *args,
            observation_spec=observation_spec,
            action_spec=action_spec,
            reward_spec=reward_spec,
            state_spec=state_spec,
            from_pixels=from_pixels,
            categorical_action_encoding=categorical_action_encoding,
            **kwargs,
        )

    def _get_out_obs(self, obs):
        obs = torch.diag_embed(obs, 0, -2, -1).unsqueeze(-1)
        obs = obs.expand(*obs.shape[:-1], 3)
        return obs

    def _get_in_obs(self, obs):
        return obs.diagonal(0, -2, -3)[..., 0, :]

    def _obs_step(self, obs, a):
        return obs + a.unsqueeze(-1) / self.maxstep


class ContinuousActionConvMockEnv(ContinuousActionVecMockEnv):
    @classmethod
    def __new__(
        cls,
        *args,
        observation_spec=None,
        action_spec=None,
        state_spec=None,
        reward_spec=None,
        done_spec=None,
        from_pixels=True,
        pixel_shape=None,
        **kwargs,
    ):
        batch_size = kwargs.setdefault("batch_size", torch.Size([]))
        if pixel_shape is None:
            pixel_shape = [1, 7, 7]
        if observation_spec is None:
            cls.out_key = "pixels"
            observation_spec = CompositeSpec(
                pixels=UnboundedContinuousTensorSpec(
                    shape=torch.Size([*batch_size, *pixel_shape])
                ),
                pixels_orig=UnboundedContinuousTensorSpec(
                    shape=torch.Size([*batch_size, *pixel_shape])
                ),
                shape=batch_size,
            )

        if action_spec is None:
            action_spec = BoundedTensorSpec(-1, 1, [*batch_size, pixel_shape[-1]])
        if reward_spec is None:
            reward_spec = UnboundedContinuousTensorSpec(shape=(*batch_size, 1))
        if done_spec is None:
            done_spec = DiscreteTensorSpec(2, dtype=torch.bool, shape=(*batch_size, 1))
        if state_spec is None:
            cls._out_key = "pixels_orig"
            state_spec = CompositeSpec(
                {cls._out_key: observation_spec["pixels"]}, shape=batch_size
            )
        return super().__new__(
            *args,
            observation_spec=observation_spec,
            action_spec=action_spec,
            reward_spec=reward_spec,
            from_pixels=from_pixels,
            state_spec=state_spec,
            done_spec=done_spec,
            **kwargs,
        )

    def _get_out_obs(self, obs):
        obs = torch.diag_embed(obs, 0, -2, -1)
        return obs

    def _get_in_obs(self, obs):
        obs = obs.diagonal(0, -1, -2)
        return obs


class ContinuousActionConvMockEnvNumpy(ContinuousActionConvMockEnv):
    @classmethod
    def __new__(
        cls,
        *args,
        observation_spec=None,
        action_spec=None,
        state_spec=None,
        reward_spec=None,
        done_spec=None,
        from_pixels=True,
        **kwargs,
    ):
        batch_size = kwargs.setdefault("batch_size", torch.Size([]))
        if observation_spec is None:
            cls.out_key = "pixels"
            observation_spec = CompositeSpec(
                pixels=UnboundedContinuousTensorSpec(
                    shape=torch.Size([*batch_size, 7, 7, 3])
                ),
                pixels_orig=UnboundedContinuousTensorSpec(
                    shape=torch.Size([*batch_size, 7, 7, 3])
                ),
            )
        return super().__new__(
            *args,
            observation_spec=observation_spec,
            action_spec=action_spec,
            reward_spec=reward_spec,
            state_spec=state_spec,
            from_pixels=from_pixels,
            **kwargs,
        )

    def _get_out_obs(self, obs):
        obs = torch.diag_embed(obs, 0, -2, -1).unsqueeze(-1)
        obs = obs.expand(*obs.shape[:-1], 3)
        return obs

    def _get_in_obs(self, obs):
        return obs.diagonal(0, -2, -3)[..., 0, :]

    def _obs_step(self, obs, a):
        return obs + a / self.maxstep


class DiscreteActionConvPolicy(DiscreteActionVecPolicy):
    in_keys = ["pixels"]
    out_keys = ["action"]

    def _get_in_obs(self, tensordict):
        obs = tensordict.get(*self.in_keys).diagonal(0, -1, -2).squeeze()
        return obs


class DummyModelBasedEnvBase(ModelBasedEnvBase):
    """Dummy environnement for Model Based RL algorithms.

    This class is meant to be used to test the model based environnement.

    Args:
        world_model (WorldModel): the world model to use for the environnement.
        device (str or torch.device, optional): the device to use for the environnement.
        dtype (torch.dtype, optional): the dtype to use for the environnement.
        batch_size (sequence of int, optional): the batch size to use for the environnement.
    """

    def __init__(
        self,
        world_model,
        device="cpu",
        dtype=None,
        batch_size=None,
    ):
        super().__init__(
            world_model,
            device=device,
            dtype=dtype,
            batch_size=batch_size,
        )
        self.observation_spec = CompositeSpec(
            hidden_observation=UnboundedContinuousTensorSpec(
                (
                    *self.batch_size,
                    4,
                )
            ),
            shape=self.batch_size,
        )
        self.state_spec = CompositeSpec(
            hidden_observation=UnboundedContinuousTensorSpec(
                (
                    *self.batch_size,
                    4,
                )
            ),
            shape=self.batch_size,
        )
        self.action_spec = UnboundedContinuousTensorSpec(
            (
                *self.batch_size,
                1,
            )
        )
        self.reward_spec = UnboundedContinuousTensorSpec(
            (
                *self.batch_size,
                1,
            )
        )

    def _reset(self, tensordict: TensorDict, **kwargs) -> TensorDict:
        td = TensorDict(
            {
                "hidden_observation": self.state_spec["hidden_observation"].rand(),
            },
            batch_size=self.batch_size,
            device=self.device,
        )
        return td


class ActionObsMergeLinear(nn.Module):
    def __init__(self, in_size, out_size):
        super().__init__()
        self.linear = nn.Linear(in_size, out_size)

    def forward(self, observation, action):
        return self.linear(torch.cat([observation, action], dim=-1))


class CountingEnvCountPolicy:
    def __init__(self, action_spec: TensorSpec, action_key: NestedKey = "action"):
        self.action_spec = action_spec
        self.action_key = action_key

    def __call__(self, td: TensorDictBase) -> TensorDictBase:
        return td.set(self.action_key, self.action_spec.zero() + 1)


class CountingEnvCountModule(nn.Module):
    def __init__(self, action_spec: TensorSpec):
        super().__init__()
        self.action_spec = action_spec

    def forward(self, t):
        return self.action_spec.zero() + 1


class CountingEnv(EnvBase):
    """An env that is done after a given number of steps.

    The action is the count increment.

    """

    def __init__(self, max_steps: int = 5, start_val: int = 0, **kwargs):
        super().__init__(**kwargs)
        self.max_steps = max_steps
        self.start_val = start_val

        self.observation_spec = CompositeSpec(
            observation=UnboundedContinuousTensorSpec(
                (
                    *self.batch_size,
                    1,
                ),
                dtype=torch.int32,
                device=self.device,
            ),
            shape=self.batch_size,
            device=self.device,
        )
        self.reward_spec = UnboundedContinuousTensorSpec(
            (
                *self.batch_size,
                1,
            ),
            device=self.device,
        )
        self.done_spec = DiscreteTensorSpec(
            2,
            dtype=torch.bool,
            shape=(
                *self.batch_size,
                1,
            ),
            device=self.device,
        )
        self.action_spec = BinaryDiscreteTensorSpec(
            n=1, shape=[*self.batch_size, 1], device=self.device
        )
        self.register_buffer(
            "count",
            torch.zeros((*self.batch_size, 1), device=self.device, dtype=torch.int),
        )

    def _set_seed(self, seed: Optional[int]):
        torch.manual_seed(seed)

    def _reset(self, tensordict: TensorDictBase, **kwargs) -> TensorDictBase:
        if tensordict is not None and "_reset" in tensordict.keys():
            _reset = tensordict.get("_reset")
            self.count[_reset] = self.start_val
        else:
            self.count[:] = self.start_val
        return TensorDict(
            source={
                "observation": self.count.clone(),
                "done": self.count > self.max_steps,
                "terminated": self.count > self.max_steps,
            },
            batch_size=self.batch_size,
            device=self.device,
        )

    def _step(
        self,
        tensordict: TensorDictBase,
    ) -> TensorDictBase:
        action = tensordict.get(self.action_key)
        self.count += action.to(torch.int).to(self.device)
        tensordict = TensorDict(
            source={
                "observation": self.count.clone(),
                "done": self.count > self.max_steps,
                "terminated": self.count > self.max_steps,
                "reward": torch.zeros_like(self.count, dtype=torch.float),
            },
            batch_size=self.batch_size,
            device=self.device,
        )
        return tensordict


class IncrementingEnv(CountingEnv):
    # Same as CountingEnv but always increments the count by 1 regardless of the action.
    def _step(
        self,
        tensordict: TensorDictBase,
    ) -> TensorDictBase:
        self.count += 1  # The only difference with CountingEnv.
        tensordict = TensorDict(
            source={
                "observation": self.count.clone(),
                "done": self.count > self.max_steps,
                "terminated": self.count > self.max_steps,
                "reward": torch.zeros_like(self.count, dtype=torch.float),
            },
            batch_size=self.batch_size,
            device=self.device,
        )
        return tensordict


class NestedCountingEnv(CountingEnv):
    # an env with nested reward and done states
    def __init__(
        self,
        max_steps: int = 5,
        start_val: int = 0,
        nest_obs_action: bool = True,
        nest_done: bool = True,
        nest_reward: bool = True,
        nested_dim: int = 3,
        **kwargs,
    ):
        super().__init__(max_steps=max_steps, start_val=start_val, **kwargs)

        self.nested_dim = nested_dim

        self.nested_obs_action = nest_obs_action
        self.nested_done = nest_done
        self.nested_reward = nest_reward

        if self.nested_obs_action:
            self.observation_spec = CompositeSpec(
                {
                    "data": CompositeSpec(
                        {
                            "states": self.observation_spec["observation"]
                            .unsqueeze(-1)
                            .expand(*self.batch_size, self.nested_dim, 1)
                        },
                        shape=(
                            *self.batch_size,
                            self.nested_dim,
                        ),
                    )
                },
                shape=self.batch_size,
            )
            self.action_spec = CompositeSpec(
                {
                    "data": CompositeSpec(
                        {
                            "action": self.action_spec.unsqueeze(-1).expand(
                                *self.batch_size, self.nested_dim, 1
                            )
                        },
                        shape=(
                            *self.batch_size,
                            self.nested_dim,
                        ),
                    )
                },
                shape=self.batch_size,
            )

        if self.nested_reward:
            self.reward_spec = CompositeSpec(
                {
                    "data": CompositeSpec(
                        {
                            "reward": self.reward_spec.unsqueeze(-1).expand(
                                *self.batch_size, self.nested_dim, 1
                            )
                        },
                        shape=(
                            *self.batch_size,
                            self.nested_dim,
                        ),
                    )
                },
                shape=self.batch_size,
            )

        if self.nested_done:
            done_spec = self.full_done_spec.unsqueeze(-1).expand(
                *self.batch_size, self.nested_dim
            )
            self.done_spec = CompositeSpec(
                {"data": done_spec},
                shape=self.batch_size,
            )

    def _reset(self, tensordict):
        if (
            self.nested_done
            and tensordict is not None
            and "_reset" in tensordict.keys()
        ):
            tensordict = tensordict.clone()
            tensordict["_reset"] = tensordict["_reset"].sum(-2, dtype=torch.bool)
        td = super()._reset(tensordict)
        if self.nested_done:
            for done_key in self.done_keys:
                if isinstance(done_key, str):
                    done_key = (done_key,)
                td[done_key] = (
                    td[done_key[-1]]
                    .unsqueeze(-1)
                    .expand(*self.batch_size, self.nested_dim, 1)
                )
                del td[done_key[-1]]
        if self.nested_obs_action:
            td["data", "states"] = (
                td["observation"]
                .unsqueeze(-1)
                .expand(*self.batch_size, self.nested_dim, 1)
            )
            del td["observation"]
        if "data" in td.keys():
            td["data"].batch_size = (*self.batch_size, self.nested_dim)
        return td

    def _step(self, td):
        if self.nested_obs_action:
            td = td.clone()
            td["data"].batch_size = self.batch_size
            td[self.action_key] = td[self.action_key].max(-2)[0]
        next_td = super()._step(td)
        if self.nested_obs_action:
            td[self.action_key] = (
                td[self.action_key]
                .unsqueeze(-1)
                .expand(*self.batch_size, self.nested_dim, 1)
            )
        if "data" in td.keys():
            td["data"].batch_size = (*self.batch_size, self.nested_dim)
        td = next_td
        if self.nested_done:
            for done_key in self.done_keys:
                if isinstance(done_key, str):
                    done_key = (done_key,)
                td[done_key] = (
                    td[done_key[-1]]
                    .unsqueeze(-1)
                    .expand(*self.batch_size, self.nested_dim, 1)
                )
                del td[done_key[-1]]
        if self.nested_obs_action:
            td["data", "states"] = (
                td["observation"]
                .unsqueeze(-1)
                .expand(*self.batch_size, self.nested_dim, 1)
            )
            del td["observation"]
        if self.nested_reward:
            td[self.reward_key] = (
                td["reward"].unsqueeze(-1).expand(*self.batch_size, self.nested_dim, 1)
            )
            del td["reward"]
        if "data" in td.keys():
            td["data"].batch_size = (*self.batch_size, self.nested_dim)
        return td


class CountingBatchedEnv(EnvBase):
    """An env that is done after a given number of steps.

    The action is the count increment.

    Unlike ``CountingEnv``, different envs of the batch can have different max_steps
    """

    def __init__(
        self,
        max_steps: torch.Tensor = None,
        start_val: torch.Tensor = None,
        **kwargs,
    ):
        super().__init__(**kwargs)
        if max_steps is None:
            max_steps = torch.tensor(5)
        if start_val is None:
            start_val = torch.zeros((), dtype=torch.int32)
        if not max_steps.shape == self.batch_size:
            raise RuntimeError("batch_size and max_steps shape must match.")

        self.max_steps = max_steps

        self.observation_spec = CompositeSpec(
            observation=UnboundedContinuousTensorSpec(
                (
                    *self.batch_size,
                    1,
                ),
                dtype=torch.int32,
            ),
            shape=self.batch_size,
        )
        self.reward_spec = UnboundedContinuousTensorSpec(
            (
                *self.batch_size,
                1,
            )
        )
        self.done_spec = DiscreteTensorSpec(
            2,
            dtype=torch.bool,
            shape=(
                *self.batch_size,
                1,
            ),
        )
        self.action_spec = BinaryDiscreteTensorSpec(n=1, shape=[*self.batch_size, 1])

        self.count = torch.zeros(
            (*self.batch_size, 1), device=self.device, dtype=torch.int
        )
        if start_val.numel() == self.batch_size.numel():
            self.start_val = start_val.view(*self.batch_size, 1)
        elif start_val.numel() <= 1:
            self.start_val = start_val.expand_as(self.count)

    def _set_seed(self, seed: Optional[int]):
        torch.manual_seed(seed)

    def _reset(self, tensordict: TensorDictBase, **kwargs) -> TensorDictBase:
        if tensordict is not None and "_reset" in tensordict.keys():
            _reset = tensordict.get("_reset")
            self.count[_reset] = self.start_val[_reset].view_as(self.count[_reset])
        else:
            self.count[:] = self.start_val.view_as(self.count)
        return TensorDict(
            source={
                "observation": self.count.clone(),
                "done": self.count > self.max_steps.view_as(self.count),
                "terminated": self.count > self.max_steps.view_as(self.count),
            },
            batch_size=self.batch_size,
            device=self.device,
        )

    def _step(
        self,
        tensordict: TensorDictBase,
    ) -> TensorDictBase:
        action = tensordict.get("action")
        self.count += action.to(torch.int).view_as(self.count)
        tensordict = TensorDict(
            source={
                "observation": self.count.clone(),
                "done": self.count > self.max_steps.unsqueeze(-1),
                "terminated": self.count > self.max_steps.unsqueeze(-1),
                "reward": torch.zeros_like(self.count, dtype=torch.float),
            },
            batch_size=self.batch_size,
            device=self.device,
        )
        return tensordict


class HeteroCountingEnvPolicy:
    def __init__(self, full_action_spec: TensorSpec, count: bool = True):
        self.full_action_spec = full_action_spec
        self.count = count

    def __call__(self, td: TensorDictBase) -> TensorDictBase:
        action_td = self.full_action_spec.zero()
        if self.count:
            action_td.apply_(lambda x: x + 1)
        return td.update(action_td)


class HeteroCountingEnv(EnvBase):
    """A heterogeneous, counting Env."""

    def __init__(self, max_steps: int = 5, start_val: int = 0, **kwargs):
        super().__init__(**kwargs)
        self.n_nested_dim = 3
        self.max_steps = max_steps
        self.start_val = start_val

        count = torch.zeros((*self.batch_size, 1), device=self.device, dtype=torch.int)
        count[:] = self.start_val

        self.register_buffer("count", count)

        obs_specs = []
        action_specs = []
        for index in range(self.n_nested_dim):
            obs_specs.append(self.get_agent_obs_spec(index))
            action_specs.append(self.get_agent_action_spec(index))
        obs_specs = torch.stack(obs_specs, dim=0)
        obs_spec_unlazy = consolidate_spec(obs_specs)
        action_specs = torch.stack(action_specs, dim=0)

        self.unbatched_observation_spec = CompositeSpec(
            lazy=obs_spec_unlazy,
            state=UnboundedContinuousTensorSpec(
                shape=(
                    64,
                    64,
                    3,
                )
            ),
        )

        self.unbatched_action_spec = CompositeSpec(
            lazy=action_specs,
        )
        self.unbatched_reward_spec = CompositeSpec(
            {
                "lazy": CompositeSpec(
                    {
                        "reward": UnboundedContinuousTensorSpec(
                            shape=(self.n_nested_dim, 1)
                        )
                    },
                    shape=(self.n_nested_dim,),
                )
            }
        )
        self.unbatched_done_spec = CompositeSpec(
            {
                "lazy": CompositeSpec(
                    {
                        "done": DiscreteTensorSpec(
                            n=2,
                            shape=(self.n_nested_dim, 1),
                            dtype=torch.bool,
                        ),
                    },
                    shape=(self.n_nested_dim,),
                )
            }
        )

        self.action_spec = self.unbatched_action_spec.expand(
            *self.batch_size, *self.unbatched_action_spec.shape
        )
        self.observation_spec = self.unbatched_observation_spec.expand(
            *self.batch_size, *self.unbatched_observation_spec.shape
        )
        self.reward_spec = self.unbatched_reward_spec.expand(
            *self.batch_size, *self.unbatched_reward_spec.shape
        )
        self.done_spec = self.unbatched_done_spec.expand(
            *self.batch_size, *self.unbatched_done_spec.shape
        )

    def get_agent_obs_spec(self, i):
        camera = BoundedTensorSpec(low=0, high=200, shape=(7, 7, 3))
        vector_3d = UnboundedContinuousTensorSpec(shape=(3,))
        vector_2d = UnboundedContinuousTensorSpec(shape=(2,))
        lidar = BoundedTensorSpec(low=0, high=5, shape=(8,))

        tensor_0 = UnboundedContinuousTensorSpec(shape=(1,))
        tensor_1 = BoundedTensorSpec(low=0, high=3, shape=(1, 2))
        tensor_2 = UnboundedContinuousTensorSpec(shape=(1, 2, 3))

        if i == 0:
            return CompositeSpec(
                {
                    "camera": camera,
                    "lidar": lidar,
                    "vector": vector_3d,
                    "tensor_0": tensor_0,
                }
            )
        elif i == 1:
            return CompositeSpec(
                {
                    "camera": camera,
                    "lidar": lidar,
                    "vector": vector_2d,
                    "tensor_1": tensor_1,
                }
            )
        elif i == 2:
            return CompositeSpec(
                {
                    "camera": camera,
                    "vector": vector_2d,
                    "tensor_2": tensor_2,
                }
            )
        else:
            raise ValueError(f"Index {i} undefined for index 3")

    def get_agent_action_spec(self, i):
        action_3d = BoundedTensorSpec(low=-1, high=1, shape=(3,))
        action_2d = BoundedTensorSpec(low=-1, high=1, shape=(2,))

        # Some have 2d action and some 3d
        # TODO Introduce composite heterogeneous actions
        if i == 0:
            ret = action_3d
        elif i == 1:
            ret = action_2d
        elif i == 2:
            ret = action_2d
        else:
            raise ValueError(f"Index {i} undefined for index 3")

        return CompositeSpec({"action": ret})

    def _reset(
        self,
        tensordict: TensorDictBase = None,
        **kwargs,
    ) -> TensorDictBase:
        if tensordict is not None and self.reset_keys[0] in tensordict.keys(True):
            _reset = tensordict.get(self.reset_keys[0]).squeeze(-1).any(-1)
            self.count[_reset] = self.start_val
        else:
            self.count[:] = self.start_val

        reset_td = self.observation_spec.zero()
        reset_td.apply_(lambda x: x + expand_right(self.count, x.shape))
        reset_td.update(self.output_spec["full_done_spec"].zero())

        assert reset_td.batch_size == self.batch_size

        return reset_td

    def _step(
        self,
        tensordict: TensorDictBase,
    ) -> TensorDictBase:
        actions = torch.zeros_like(self.count.squeeze(-1), dtype=torch.bool)
        for i in range(self.n_nested_dim):
            action = tensordict["lazy"][..., i]["action"]
            action = action[..., 0].to(torch.bool)
            actions += action

        self.count += actions.unsqueeze(-1).to(torch.int)

        td = self.observation_spec.zero()
        td.apply_(lambda x: x + expand_right(self.count, x.shape))
        td.update(self.output_spec["full_done_spec"].zero())
        td.update(self.output_spec["full_reward_spec"].zero())

        assert td.batch_size == self.batch_size
        for done_key in self.done_keys:
            td[done_key] = expand_right(
                self.count > self.max_steps,
                self.full_done_spec[done_key].shape,
            )

        return td

    def _set_seed(self, seed: Optional[int]):
        torch.manual_seed(seed)


class MultiKeyCountingEnvPolicy:
    def __init__(
        self,
        full_action_spec: TensorSpec,
        count: bool = True,
        deterministic: bool = False,
    ):
        if not deterministic and not count:
            raise ValueError("Not counting policy is always deterministic")

        self.full_action_spec = full_action_spec
        self.count = count
        self.deterministic = deterministic

    def __call__(self, td: TensorDictBase) -> TensorDictBase:
        action_td = self.full_action_spec.zero()
        if self.count:
            if self.deterministic:
                action_td["nested_1", "action"] += 1
                action_td["nested_2", "azione"] += 1
                action_td["action"][..., 1] = 1
            else:
                # We choose an action at random
                choice = torch.randint(0, 3, ()).item()
                if choice == 0:
                    action_td["nested_1", "action"] += 1
                elif choice == 1:
                    action_td["nested_2", "azione"] += 1
                else:
                    action_td["action"][..., 1] = 1
        return td.update(action_td)


class MultiKeyCountingEnv(EnvBase):
    def __init__(self, max_steps: int = 5, start_val: int = 0, **kwargs):
        super().__init__(**kwargs)

        self.max_steps = max_steps
        self.start_val = start_val
        self.nested_dim_1 = 3
        self.nested_dim_2 = 2

        count = torch.zeros((*self.batch_size, 1), device=self.device, dtype=torch.int)
        count_nested_1 = torch.zeros(
            (*self.batch_size, self.nested_dim_1, 1),
            device=self.device,
            dtype=torch.int,
        )
        count_nested_2 = torch.zeros(
            (*self.batch_size, self.nested_dim_2, 1),
            device=self.device,
            dtype=torch.int,
        )

        count[:] = self.start_val
        count_nested_1[:] = self.start_val
        count_nested_2[:] = self.start_val

        self.register_buffer("count", count)
        self.register_buffer("count_nested_1", count_nested_1)
        self.register_buffer("count_nested_2", count_nested_2)

        self.make_specs()

        self.action_spec = self.unbatched_action_spec.expand(
            *self.batch_size, *self.unbatched_action_spec.shape
        )
        self.observation_spec = self.unbatched_observation_spec.expand(
            *self.batch_size, *self.unbatched_observation_spec.shape
        )
        self.reward_spec = self.unbatched_reward_spec.expand(
            *self.batch_size, *self.unbatched_reward_spec.shape
        )
        self.done_spec = self.unbatched_done_spec.expand(
            *self.batch_size, *self.unbatched_done_spec.shape
        )

    def make_specs(self):
        self.unbatched_observation_spec = CompositeSpec(
            nested_1=CompositeSpec(
                observation=BoundedTensorSpec(
                    low=0, high=200, shape=(self.nested_dim_1, 3)
                ),
                shape=(self.nested_dim_1,),
            ),
            nested_2=CompositeSpec(
                observation=UnboundedContinuousTensorSpec(shape=(self.nested_dim_2, 2)),
                shape=(self.nested_dim_2,),
            ),
            observation=UnboundedContinuousTensorSpec(
                shape=(
                    10,
                    10,
                    3,
                )
            ),
        )

        self.unbatched_action_spec = CompositeSpec(
            nested_1=CompositeSpec(
                action=DiscreteTensorSpec(n=2, shape=(self.nested_dim_1,)),
                shape=(self.nested_dim_1,),
            ),
            nested_2=CompositeSpec(
                azione=BoundedTensorSpec(low=0, high=100, shape=(self.nested_dim_2, 1)),
                shape=(self.nested_dim_2,),
            ),
            action=OneHotDiscreteTensorSpec(n=2),
        )

        self.unbatched_reward_spec = CompositeSpec(
            nested_1=CompositeSpec(
                gift=UnboundedContinuousTensorSpec(shape=(self.nested_dim_1, 1)),
                shape=(self.nested_dim_1,),
            ),
            nested_2=CompositeSpec(
                reward=UnboundedContinuousTensorSpec(shape=(self.nested_dim_2, 1)),
                shape=(self.nested_dim_2,),
            ),
            reward=UnboundedContinuousTensorSpec(shape=(1,)),
        )

        self.unbatched_done_spec = CompositeSpec(
            nested_1=CompositeSpec(
                done=DiscreteTensorSpec(
                    n=2,
                    shape=(self.nested_dim_1, 1),
                    dtype=torch.bool,
                ),
                terminated=DiscreteTensorSpec(
                    n=2,
                    shape=(self.nested_dim_1, 1),
                    dtype=torch.bool,
                ),
                shape=(self.nested_dim_1,),
            ),
            nested_2=CompositeSpec(
                done=DiscreteTensorSpec(
                    n=2,
                    shape=(self.nested_dim_2, 1),
                    dtype=torch.bool,
                ),
                terminated=DiscreteTensorSpec(
                    n=2,
                    shape=(self.nested_dim_2, 1),
                    dtype=torch.bool,
                ),
                shape=(self.nested_dim_2,),
            ),
            done=DiscreteTensorSpec(
                n=2,
                shape=(1,),
                dtype=torch.bool,
            ),
            terminated=DiscreteTensorSpec(
                n=2,
                shape=(1,),
                dtype=torch.bool,
            ),
        )

    def _reset(
        self,
        tensordict: TensorDictBase = None,
        **kwargs,
    ) -> TensorDictBase:
        reset_all = False
        if tensordict is not None:
            _reset = tensordict.get("_reset", None)
            if _reset is not None:
                self.count[_reset.squeeze(-1)] = self.start_val

            _reset_nested_1 = tensordict.get(("nested_1", "_reset"), None)
            if _reset_nested_1 is not None:
                self.count_nested_1[_reset_nested_1.squeeze(-1)] = self.start_val

            _reset_nested_2 = tensordict.get(("nested_2", "_reset"), None)
            if _reset_nested_2 is not None:
                self.count_nested_2[_reset_nested_2.squeeze(-1)] = self.start_val

            if _reset is None and _reset_nested_1 is None and _reset_nested_2 is None:
                reset_all = True

        if tensordict is None or reset_all:
            self.count[:] = self.start_val
            self.count_nested_1[:] = self.start_val
            self.count_nested_2[:] = self.start_val

        reset_td = self.observation_spec.zero()
        reset_td["observation"] += expand_right(
            self.count, reset_td["observation"].shape
        )
        reset_td["nested_1", "observation"] += expand_right(
            self.count_nested_1, reset_td["nested_1", "observation"].shape
        )
        reset_td["nested_2", "observation"] += expand_right(
            self.count_nested_2, reset_td["nested_2", "observation"].shape
        )

        reset_td.update(self.output_spec["full_done_spec"].zero())

        assert reset_td.batch_size == self.batch_size

        return reset_td

    def _step(
        self,
        tensordict: TensorDictBase,
    ) -> TensorDictBase:

        # Each action has a corresponding reward, done, and observation
        reward = self.output_spec["full_reward_spec"].zero()
        done = self.output_spec["full_done_spec"].zero()
        td = self.observation_spec.zero()

        one_hot_action = tensordict["action"]
        one_hot_action = one_hot_action.long().argmax(-1).unsqueeze(-1)
        reward["reward"] += one_hot_action.to(torch.float)
        self.count += one_hot_action.to(torch.int)
        td["observation"] += expand_right(self.count, td["observation"].shape)
        done["done"] = self.count > self.max_steps
        done["terminated"] = self.count > self.max_steps

        discrete_action = tensordict["nested_1"]["action"].unsqueeze(-1)
        reward["nested_1"]["gift"] += discrete_action.to(torch.float)
        self.count_nested_1 += discrete_action.to(torch.int)
        td["nested_1", "observation"] += expand_right(
            self.count_nested_1, td["nested_1", "observation"].shape
        )
        done["nested_1", "done"] = self.count_nested_1 > self.max_steps
        done["nested_1", "terminated"] = self.count_nested_1 > self.max_steps

        continuous_action = tensordict["nested_2"]["azione"]
        reward["nested_2"]["reward"] += continuous_action.to(torch.float)
        self.count_nested_2 += continuous_action.to(torch.bool)
        td["nested_2", "observation"] += expand_right(
            self.count_nested_2, td["nested_2", "observation"].shape
        )
        done["nested_2", "done"] = self.count_nested_2 > self.max_steps
        done["nested_2", "terminated"] = self.count_nested_2 > self.max_steps

        td.update(done)
        td.update(reward)

        assert td.batch_size == self.batch_size
        return td

    def _set_seed(self, seed: Optional[int]):
        torch.manual_seed(seed)