ray/rllib/policy/policy_template.py

453 lines
20 KiB
Python

import gym
from typing import (
Any,
Callable,
Dict,
List,
Optional,
Tuple,
Type,
TYPE_CHECKING,
Union,
)
from ray.rllib.models.catalog import ModelCatalog
from ray.rllib.models.jax.jax_modelv2 import JAXModelV2
from ray.rllib.models.modelv2 import ModelV2
from ray.rllib.models.torch.torch_action_dist import TorchDistributionWrapper
from ray.rllib.models.torch.torch_modelv2 import TorchModelV2
from ray.rllib.policy.policy import Policy
from ray.rllib.policy.sample_batch import SampleBatch
from ray.rllib.policy.torch_policy import TorchPolicy
from ray.rllib.utils import add_mixins, NullContextManager
from ray.rllib.utils.annotations import override, DeveloperAPI
from ray.rllib.utils.framework import try_import_torch, try_import_jax
from ray.rllib.utils.metrics.learner_info import LEARNER_STATS_KEY
from ray.rllib.utils.numpy import convert_to_numpy
from ray.rllib.utils.typing import ModelGradients, TensorType, TrainerConfigDict
if TYPE_CHECKING:
from ray.rllib.evaluation.episode import Episode # noqa
jax, _ = try_import_jax()
torch, _ = try_import_torch()
# TODO: Deprecate in favor of directly sub-classing from TorchPolicy.
@DeveloperAPI
def build_policy_class(
name: str,
framework: str,
*,
loss_fn: Optional[
Callable[
[Policy, ModelV2, Type[TorchDistributionWrapper], SampleBatch],
Union[TensorType, List[TensorType]],
]
],
get_default_config: Optional[Callable[[], TrainerConfigDict]] = None,
stats_fn: Optional[Callable[[Policy, SampleBatch], Dict[str, TensorType]]] = None,
postprocess_fn: Optional[
Callable[
[
Policy,
SampleBatch,
Optional[Dict[Any, SampleBatch]],
Optional["Episode"],
],
SampleBatch,
]
] = None,
extra_action_out_fn: Optional[
Callable[
[
Policy,
Dict[str, TensorType],
List[TensorType],
ModelV2,
TorchDistributionWrapper,
],
Dict[str, TensorType],
]
] = None,
extra_grad_process_fn: Optional[
Callable[[Policy, "torch.optim.Optimizer", TensorType], Dict[str, TensorType]]
] = None,
# TODO: (sven) Replace "fetches" with "process".
extra_learn_fetches_fn: Optional[Callable[[Policy], Dict[str, TensorType]]] = None,
optimizer_fn: Optional[
Callable[[Policy, TrainerConfigDict], "torch.optim.Optimizer"]
] = None,
validate_spaces: Optional[
Callable[[Policy, gym.Space, gym.Space, TrainerConfigDict], None]
] = None,
before_init: Optional[
Callable[[Policy, gym.Space, gym.Space, TrainerConfigDict], None]
] = None,
before_loss_init: Optional[
Callable[[Policy, gym.spaces.Space, gym.spaces.Space, TrainerConfigDict], None]
] = None,
after_init: Optional[
Callable[[Policy, gym.Space, gym.Space, TrainerConfigDict], None]
] = None,
_after_loss_init: Optional[
Callable[[Policy, gym.spaces.Space, gym.spaces.Space, TrainerConfigDict], None]
] = None,
action_sampler_fn: Optional[
Callable[[TensorType, List[TensorType]], Tuple[TensorType, TensorType]]
] = None,
action_distribution_fn: Optional[
Callable[
[Policy, ModelV2, TensorType, TensorType, TensorType],
Tuple[TensorType, type, List[TensorType]],
]
] = None,
make_model: Optional[
Callable[
[Policy, gym.spaces.Space, gym.spaces.Space, TrainerConfigDict], ModelV2
]
] = None,
make_model_and_action_dist: Optional[
Callable[
[Policy, gym.spaces.Space, gym.spaces.Space, TrainerConfigDict],
Tuple[ModelV2, Type[TorchDistributionWrapper]],
]
] = None,
compute_gradients_fn: Optional[
Callable[[Policy, SampleBatch], Tuple[ModelGradients, dict]]
] = None,
apply_gradients_fn: Optional[
Callable[[Policy, "torch.optim.Optimizer"], None]
] = None,
mixins: Optional[List[type]] = None,
get_batch_divisibility_req: Optional[Callable[[Policy], int]] = None
) -> Type[TorchPolicy]:
"""Helper function for creating a new Policy class at runtime.
Supports frameworks JAX and PyTorch.
Args:
name: name of the policy (e.g., "PPOTorchPolicy")
framework: Either "jax" or "torch".
loss_fn (Optional[Callable[[Policy, ModelV2,
Type[TorchDistributionWrapper], SampleBatch], Union[TensorType,
List[TensorType]]]]): Callable that returns a loss tensor.
get_default_config (Optional[Callable[[None], TrainerConfigDict]]):
Optional callable that returns the default config to merge with any
overrides. If None, uses only(!) the user-provided
PartialTrainerConfigDict as dict for this Policy.
postprocess_fn (Optional[Callable[[Policy, SampleBatch,
Optional[Dict[Any, SampleBatch]], Optional["Episode"]],
SampleBatch]]): Optional callable for post-processing experience
batches (called after the super's `postprocess_trajectory` method).
stats_fn (Optional[Callable[[Policy, SampleBatch],
Dict[str, TensorType]]]): Optional callable that returns a dict of
values given the policy and training batch. If None,
will use `TorchPolicy.extra_grad_info()` instead. The stats dict is
used for logging (e.g. in TensorBoard).
extra_action_out_fn (Optional[Callable[[Policy, Dict[str, TensorType],
List[TensorType], ModelV2, TorchDistributionWrapper]], Dict[str,
TensorType]]]): Optional callable that returns a dict of extra
values to include in experiences. If None, no extra computations
will be performed.
extra_grad_process_fn (Optional[Callable[[Policy,
"torch.optim.Optimizer", TensorType], Dict[str, TensorType]]]):
Optional callable that is called after gradients are computed and
returns a processing info dict. If None, will call the
`TorchPolicy.extra_grad_process()` method instead.
# TODO: (sven) dissolve naming mismatch between "learn" and "compute.."
extra_learn_fetches_fn (Optional[Callable[[Policy],
Dict[str, TensorType]]]): Optional callable that returns a dict of
extra tensors from the policy after loss evaluation. If None,
will call the `TorchPolicy.extra_compute_grad_fetches()` method
instead.
optimizer_fn (Optional[Callable[[Policy, TrainerConfigDict],
"torch.optim.Optimizer"]]): Optional callable that returns a
torch optimizer given the policy and config. If None, will call
the `TorchPolicy.optimizer()` method instead (which returns a
torch Adam optimizer).
validate_spaces (Optional[Callable[[Policy, gym.Space, gym.Space,
TrainerConfigDict], None]]): Optional callable that takes the
Policy, observation_space, action_space, and config to check for
correctness. If None, no spaces checking will be done.
before_init (Optional[Callable[[Policy, gym.Space, gym.Space,
TrainerConfigDict], None]]): Optional callable to run at the
beginning of `Policy.__init__` that takes the same arguments as
the Policy constructor. If None, this step will be skipped.
before_loss_init (Optional[Callable[[Policy, gym.spaces.Space,
gym.spaces.Space, TrainerConfigDict], None]]): Optional callable to
run prior to loss init. If None, this step will be skipped.
after_init (Optional[Callable[[Policy, gym.Space, gym.Space,
TrainerConfigDict], None]]): DEPRECATED: Use `before_loss_init`
instead.
_after_loss_init (Optional[Callable[[Policy, gym.spaces.Space,
gym.spaces.Space, TrainerConfigDict], None]]): Optional callable to
run after the loss init. If None, this step will be skipped.
This will be deprecated at some point and renamed into `after_init`
to match `build_tf_policy()` behavior.
action_sampler_fn (Optional[Callable[[TensorType, List[TensorType]],
Tuple[TensorType, TensorType]]]): Optional callable returning a
sampled action and its log-likelihood given some (obs and state)
inputs. If None, will either use `action_distribution_fn` or
compute actions by calling self.model, then sampling from the
so parameterized action distribution.
action_distribution_fn (Optional[Callable[[Policy, ModelV2, TensorType,
TensorType, TensorType], Tuple[TensorType,
Type[TorchDistributionWrapper], List[TensorType]]]]): A callable
that takes the Policy, Model, the observation batch, an
explore-flag, a timestep, and an is_training flag and returns a
tuple of a) distribution inputs (parameters), b) a dist-class to
generate an action distribution object from, and c) internal-state
outputs (empty list if not applicable). If None, will either use
`action_sampler_fn` or compute actions by calling self.model,
then sampling from the parameterized action distribution.
make_model (Optional[Callable[[Policy, gym.spaces.Space,
gym.spaces.Space, TrainerConfigDict], ModelV2]]): Optional callable
that takes the same arguments as Policy.__init__ and returns a
model instance. The distribution class will be determined
automatically. Note: Only one of `make_model` or
`make_model_and_action_dist` should be provided. If both are None,
a default Model will be created.
make_model_and_action_dist (Optional[Callable[[Policy,
gym.spaces.Space, gym.spaces.Space, TrainerConfigDict],
Tuple[ModelV2, Type[TorchDistributionWrapper]]]]): Optional
callable that takes the same arguments as Policy.__init__ and
returns a tuple of model instance and torch action distribution
class.
Note: Only one of `make_model` or `make_model_and_action_dist`
should be provided. If both are None, a default Model will be
created.
compute_gradients_fn (Optional[Callable[
[Policy, SampleBatch], Tuple[ModelGradients, dict]]]): Optional
callable that the sampled batch an computes the gradients w.r.
to the loss function.
If None, will call the `TorchPolicy.compute_gradients()` method
instead.
apply_gradients_fn (Optional[Callable[[Policy,
"torch.optim.Optimizer"], None]]): Optional callable that
takes a grads list and applies these to the Model's parameters.
If None, will call the `TorchPolicy.apply_gradients()` method
instead.
mixins (Optional[List[type]]): Optional list of any class mixins for
the returned policy class. These mixins will be applied in order
and will have higher precedence than the TorchPolicy class.
get_batch_divisibility_req (Optional[Callable[[Policy], int]]):
Optional callable that returns the divisibility requirement for
sample batches. If None, will assume a value of 1.
Returns:
Type[TorchPolicy]: TorchPolicy child class constructed from the
specified args.
"""
original_kwargs = locals().copy()
parent_cls = TorchPolicy
base = add_mixins(parent_cls, mixins)
class policy_cls(base):
def __init__(self, obs_space, action_space, config):
# Set up the config from possible default-config fn and given
# config arg.
if get_default_config:
config = dict(get_default_config(), **config)
self.config = config
# Set the DL framework for this Policy.
self.framework = self.config["framework"] = framework
# Validate observation- and action-spaces.
if validate_spaces:
validate_spaces(self, obs_space, action_space, self.config)
# Do some pre-initialization steps.
if before_init:
before_init(self, obs_space, action_space, self.config)
# Model is customized (use default action dist class).
if make_model:
assert make_model_and_action_dist is None, (
"Either `make_model` or `make_model_and_action_dist`"
" must be None!"
)
self.model = make_model(self, obs_space, action_space, config)
dist_class, _ = ModelCatalog.get_action_dist(
action_space, self.config["model"], framework=framework
)
# Model and action dist class are customized.
elif make_model_and_action_dist:
self.model, dist_class = make_model_and_action_dist(
self, obs_space, action_space, config
)
# Use default model and default action dist.
else:
dist_class, logit_dim = ModelCatalog.get_action_dist(
action_space, self.config["model"], framework=framework
)
self.model = ModelCatalog.get_model_v2(
obs_space=obs_space,
action_space=action_space,
num_outputs=logit_dim,
model_config=self.config["model"],
framework=framework,
)
# Make sure, we passed in a correct Model factory.
model_cls = TorchModelV2 if framework == "torch" else JAXModelV2
assert isinstance(
self.model, model_cls
), "ERROR: Generated Model must be a TorchModelV2 object!"
# Call the framework-specific Policy constructor.
self.parent_cls = parent_cls
self.parent_cls.__init__(
self,
observation_space=obs_space,
action_space=action_space,
config=config,
model=self.model,
loss=None if self.config["in_evaluation"] else loss_fn,
action_distribution_class=dist_class,
action_sampler_fn=action_sampler_fn,
action_distribution_fn=action_distribution_fn,
max_seq_len=config["model"]["max_seq_len"],
get_batch_divisibility_req=get_batch_divisibility_req,
)
# Merge Model's view requirements into Policy's.
self.view_requirements.update(self.model.view_requirements)
_before_loss_init = before_loss_init or after_init
if _before_loss_init:
_before_loss_init(
self, self.observation_space, self.action_space, config
)
# Perform test runs through postprocessing- and loss functions.
self._initialize_loss_from_dummy_batch(
auto_remove_unneeded_view_reqs=True,
stats_fn=None if self.config["in_evaluation"] else stats_fn,
)
if _after_loss_init:
_after_loss_init(self, obs_space, action_space, config)
# Got to reset global_timestep again after this fake run-through.
self.global_timestep = 0
@override(Policy)
def postprocess_trajectory(
self, sample_batch, other_agent_batches=None, episode=None
):
# Do all post-processing always with no_grad().
# Not using this here will introduce a memory leak
# in torch (issue #6962).
with self._no_grad_context():
# Call super's postprocess_trajectory first.
sample_batch = super().postprocess_trajectory(
sample_batch, other_agent_batches, episode
)
if postprocess_fn:
return postprocess_fn(
self, sample_batch, other_agent_batches, episode
)
return sample_batch
@override(parent_cls)
def extra_grad_process(self, optimizer, loss):
"""Called after optimizer.zero_grad() and loss.backward() calls.
Allows for gradient processing before optimizer.step() is called.
E.g. for gradient clipping.
"""
if extra_grad_process_fn:
return extra_grad_process_fn(self, optimizer, loss)
else:
return parent_cls.extra_grad_process(self, optimizer, loss)
@override(parent_cls)
def extra_compute_grad_fetches(self):
if extra_learn_fetches_fn:
fetches = convert_to_numpy(extra_learn_fetches_fn(self))
# Auto-add empty learner stats dict if needed.
return dict({LEARNER_STATS_KEY: {}}, **fetches)
else:
return parent_cls.extra_compute_grad_fetches(self)
@override(parent_cls)
def compute_gradients(self, batch):
if compute_gradients_fn:
return compute_gradients_fn(self, batch)
else:
return parent_cls.compute_gradients(self, batch)
@override(parent_cls)
def apply_gradients(self, gradients):
if apply_gradients_fn:
apply_gradients_fn(self, gradients)
else:
parent_cls.apply_gradients(self, gradients)
@override(parent_cls)
def extra_action_out(self, input_dict, state_batches, model, action_dist):
with self._no_grad_context():
if extra_action_out_fn:
stats_dict = extra_action_out_fn(
self, input_dict, state_batches, model, action_dist
)
else:
stats_dict = parent_cls.extra_action_out(
self, input_dict, state_batches, model, action_dist
)
return self._convert_to_numpy(stats_dict)
@override(parent_cls)
def optimizer(self):
if optimizer_fn:
optimizers = optimizer_fn(self, self.config)
else:
optimizers = parent_cls.optimizer(self)
return optimizers
@override(parent_cls)
def extra_grad_info(self, train_batch):
with self._no_grad_context():
if stats_fn:
stats_dict = stats_fn(self, train_batch)
else:
stats_dict = self.parent_cls.extra_grad_info(self, train_batch)
return self._convert_to_numpy(stats_dict)
def _no_grad_context(self):
if self.framework == "torch":
return torch.no_grad()
return NullContextManager()
def _convert_to_numpy(self, data):
if self.framework == "torch":
return convert_to_numpy(data)
return data
def with_updates(**overrides):
"""Creates a Torch|JAXPolicy cls based on settings of another one.
Keyword Args:
**overrides: The settings (passed into `build_torch_policy`) that
should be different from the class that this method is called
on.
Returns:
type: A new Torch|JAXPolicy sub-class.
Examples:
>> MySpecialDQNPolicyClass = DQNTorchPolicy.with_updates(
.. name="MySpecialDQNPolicyClass",
.. loss_function=[some_new_loss_function],
.. )
"""
return build_policy_class(**dict(original_kwargs, **overrides))
policy_cls.with_updates = staticmethod(with_updates)
policy_cls.__name__ = name
policy_cls.__qualname__ = name
return policy_cls