150 lines
5.3 KiB
Python
150 lines
5.3 KiB
Python
from abc import ABC, abstractmethod
|
|
from collections.abc import Sequence
|
|
|
|
import torch
|
|
from torch import nn
|
|
|
|
from tianshou.highlevel.env import Environments, EnvType
|
|
from tianshou.highlevel.module.core import TDevice, init_linear_orthogonal
|
|
from tianshou.utils.net import continuous, discrete
|
|
from tianshou.utils.net.common import BaseActor, Net
|
|
from tianshou.utils.string import ToStringMixin
|
|
|
|
|
|
class ContinuousActorType:
|
|
GAUSSIAN = "gaussian"
|
|
DETERMINISTIC = "deterministic"
|
|
UNSUPPORTED = "unsupported"
|
|
|
|
|
|
class ActorFactory(ToStringMixin, ABC):
|
|
@abstractmethod
|
|
def create_module(self, envs: Environments, device: TDevice) -> BaseActor | nn.Module:
|
|
pass
|
|
|
|
@staticmethod
|
|
def _init_linear(actor: torch.nn.Module):
|
|
"""Initializes linear layers of an actor module using default mechanisms.
|
|
|
|
:param module: the actor module.
|
|
"""
|
|
init_linear_orthogonal(actor)
|
|
if hasattr(actor, "mu"):
|
|
# For continuous action spaces with Gaussian policies
|
|
# do last policy layer scaling, this will make initial actions have (close to)
|
|
# 0 mean and std, and will help boost performances,
|
|
# see https://arxiv.org/abs/2006.05990, Fig.24 for details
|
|
for m in actor.mu.modules():
|
|
if isinstance(m, torch.nn.Linear):
|
|
m.weight.data.copy_(0.01 * m.weight.data)
|
|
|
|
|
|
class ActorFactoryDefault(ActorFactory):
|
|
"""An actor factory which, depending on the type of environment, creates a suitable MLP-based policy."""
|
|
|
|
DEFAULT_HIDDEN_SIZES = (64, 64)
|
|
|
|
def __init__(
|
|
self,
|
|
continuous_actor_type: ContinuousActorType,
|
|
hidden_sizes: Sequence[int] = DEFAULT_HIDDEN_SIZES,
|
|
continuous_unbounded=False,
|
|
continuous_conditioned_sigma=False,
|
|
):
|
|
self.continuous_actor_type = continuous_actor_type
|
|
self.continuous_unbounded = continuous_unbounded
|
|
self.continuous_conditioned_sigma = continuous_conditioned_sigma
|
|
self.hidden_sizes = hidden_sizes
|
|
|
|
def create_module(self, envs: Environments, device: TDevice) -> BaseActor:
|
|
env_type = envs.get_type()
|
|
if env_type == EnvType.CONTINUOUS:
|
|
match self.continuous_actor_type:
|
|
case ContinuousActorType.GAUSSIAN:
|
|
factory = ActorFactoryContinuousGaussianNet(
|
|
self.hidden_sizes,
|
|
unbounded=self.continuous_unbounded,
|
|
conditioned_sigma=self.continuous_conditioned_sigma,
|
|
)
|
|
case ContinuousActorType.DETERMINISTIC:
|
|
factory = ActorFactoryContinuousDeterministicNet(self.hidden_sizes)
|
|
case ContinuousActorType.UNSUPPORTED:
|
|
raise ValueError("Continuous action spaces are not supported by the algorithm")
|
|
case _:
|
|
raise ValueError(self.continuous_actor_type)
|
|
return factory.create_module(envs, device)
|
|
elif env_type == EnvType.DISCRETE:
|
|
factory = ActorFactoryDiscreteNet(self.DEFAULT_HIDDEN_SIZES)
|
|
return factory.create_module(envs, device)
|
|
else:
|
|
raise ValueError(f"{env_type} not supported")
|
|
|
|
|
|
class ActorFactoryContinuous(ActorFactory, ABC):
|
|
"""Serves as a type bound for actor factories that are suitable for continuous action spaces."""
|
|
|
|
|
|
class ActorFactoryContinuousDeterministicNet(ActorFactoryContinuous):
|
|
def __init__(self, hidden_sizes: Sequence[int]):
|
|
self.hidden_sizes = hidden_sizes
|
|
|
|
def create_module(self, envs: Environments, device: TDevice) -> BaseActor:
|
|
net_a = Net(
|
|
envs.get_observation_shape(),
|
|
hidden_sizes=self.hidden_sizes,
|
|
device=device,
|
|
)
|
|
return continuous.Actor(
|
|
net_a,
|
|
envs.get_action_shape(),
|
|
hidden_sizes=(),
|
|
device=device,
|
|
).to(device)
|
|
|
|
|
|
class ActorFactoryContinuousGaussianNet(ActorFactoryContinuous):
|
|
def __init__(self, hidden_sizes: Sequence[int], unbounded=True, conditioned_sigma=False):
|
|
self.hidden_sizes = hidden_sizes
|
|
self.unbounded = unbounded
|
|
self.conditioned_sigma = conditioned_sigma
|
|
|
|
def create_module(self, envs: Environments, device: TDevice) -> BaseActor:
|
|
net_a = Net(
|
|
envs.get_observation_shape(),
|
|
hidden_sizes=self.hidden_sizes,
|
|
activation=nn.Tanh,
|
|
device=device,
|
|
)
|
|
actor = continuous.ActorProb(
|
|
net_a,
|
|
envs.get_action_shape(),
|
|
unbounded=self.unbounded,
|
|
device=device,
|
|
conditioned_sigma=self.conditioned_sigma,
|
|
).to(device)
|
|
|
|
# init params
|
|
if not self.conditioned_sigma:
|
|
torch.nn.init.constant_(actor.sigma_param, -0.5)
|
|
self._init_linear(actor)
|
|
|
|
return actor
|
|
|
|
|
|
class ActorFactoryDiscreteNet(ActorFactory):
|
|
def __init__(self, hidden_sizes: Sequence[int]):
|
|
self.hidden_sizes = hidden_sizes
|
|
|
|
def create_module(self, envs: Environments, device: TDevice) -> BaseActor:
|
|
net_a = Net(
|
|
envs.get_observation_shape(),
|
|
hidden_sizes=self.hidden_sizes,
|
|
device=device,
|
|
)
|
|
return discrete.Actor(
|
|
net_a,
|
|
envs.get_action_shape(),
|
|
hidden_sizes=(),
|
|
device=device,
|
|
).to(device)
|