ActorCriticWrapper

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

Actor-value operator without common module.

This class wraps together an actor and a value model that do not share a common observation embedding network:

To facilitate the workflow, this class comes with a get_policy_operator() and get_value_operator() methods, which will both return a standalone TDModule with the dedicated functionality.

Parameters:

• policy_operator (TensorDictModule) – a policy operator that reads the hidden variable and returns an action

• value_operator (TensorDictModule) – a value operator, that reads the hidden variable and returns a value

Examples

>>> import torch
>>> from tensordict import TensorDict
>>> from tensordict.nn import TensorDictModule
>>> from torchrl.modules import (
...      ActorCriticWrapper,
...      ProbabilisticActor,
...      NormalParamWrapper,
...      TanhNormal,
...      ValueOperator,
...  )
>>> action_module = TensorDictModule(
...        NormalParamWrapper(torch.nn.Linear(4, 8)),
...        in_keys=["observation"],
...        out_keys=["loc", "scale"],
...    )
>>> td_module_action = ProbabilisticActor(
...    module=action_module,
...    in_keys=["loc", "scale"],
...    distribution_class=TanhNormal,
...    return_log_prob=True,
...    )
>>> module_value = torch.nn.Linear(4, 1)
>>> td_module_value = ValueOperator(
...    module=module_value,
...    in_keys=["observation"],
...    )
>>> td_module = ActorCriticWrapper(td_module_action, td_module_value)
>>> td = TensorDict({"observation": torch.randn(3, 4)}, [3,])
>>> td_clone = td_module(td.clone())
>>> print(td_clone)
TensorDict(
    fields={
        action: Tensor(shape=torch.Size([3, 4]), device=cpu, dtype=torch.float32, is_shared=False),
        loc: Tensor(shape=torch.Size([3, 4]), device=cpu, dtype=torch.float32, is_shared=False),
        observation: Tensor(shape=torch.Size([3, 4]), device=cpu, dtype=torch.float32, is_shared=False),
        sample_log_prob: Tensor(shape=torch.Size([3]), device=cpu, dtype=torch.float32, is_shared=False),
        scale: Tensor(shape=torch.Size([3, 4]), device=cpu, dtype=torch.float32, is_shared=False),
        state_value: Tensor(shape=torch.Size([3, 1]), device=cpu, dtype=torch.float32, is_shared=False)},
    batch_size=torch.Size([3]),
    device=None,
    is_shared=False)
>>> td_clone = td_module.get_policy_operator()(td.clone())
>>> print(td_clone)  # no value
TensorDict(
    fields={
        action: Tensor(shape=torch.Size([3, 4]), device=cpu, dtype=torch.float32, is_shared=False),
        loc: Tensor(shape=torch.Size([3, 4]), device=cpu, dtype=torch.float32, is_shared=False),
        observation: Tensor(shape=torch.Size([3, 4]), device=cpu, dtype=torch.float32, is_shared=False),
        sample_log_prob: Tensor(shape=torch.Size([3]), device=cpu, dtype=torch.float32, is_shared=False),
        scale: Tensor(shape=torch.Size([3, 4]), device=cpu, dtype=torch.float32, is_shared=False)},
    batch_size=torch.Size([3]),
    device=None,
    is_shared=False)
>>> td_clone = td_module.get_value_operator()(td.clone())
>>> print(td_clone)  # no action
TensorDict(
    fields={
        observation: Tensor(shape=torch.Size([3, 4]), device=cpu, dtype=torch.float32, is_shared=False),
        state_value: Tensor(shape=torch.Size([3, 1]), device=cpu, dtype=torch.float32, is_shared=False)},
    batch_size=torch.Size([3]),
    device=None,
    is_shared=False)

get_policy_head() → SafeSequential

Returns a standalone policy operator that maps an observation to an action.

get_policy_operator() → SafeSequential

Returns a standalone policy operator that maps an observation to an action.

get_value_head() → SafeSequential

Returns a standalone value network operator that maps an observation to a value estimate.

get_value_operator() → SafeSequential

Returns a standalone value network operator that maps an observation to a value estimate.