from typing import Any, ClassVar, Dict, List, Optional, Tuple, Type, TypeVar, Union
import numpy as np
import torch as th
from gymnasium import spaces
from torch.nn import functional as F
from stable_baselines3.common.buffers import ReplayBuffer
from stable_baselines3.common.noise import ActionNoise
from stable_baselines3.common.off_policy_algorithm import OffPolicyAlgorithm
from stable_baselines3.common.policies import BasePolicy, ContinuousCritic
from stable_baselines3.common.type_aliases import GymEnv, MaybeCallback, Schedule
from stable_baselines3.common.utils import get_parameters_by_name, polyak_update
from stable_baselines3.td3.policies import Actor, CnnPolicy, MlpPolicy, MultiInputPolicy, TD3Policy
SelfTD3 = TypeVar("SelfTD3", bound="TD3")
[docs]class TD3(OffPolicyAlgorithm):
"""
Twin Delayed DDPG (TD3)
Addressing Function Approximation Error in Actor-Critic Methods.
Original implementation: https://github.com/sfujim/TD3
Paper: https://arxiv.org/abs/1802.09477
Introduction to TD3: https://spinningup.openai.com/en/latest/algorithms/td3.html
:param policy: The policy model to use (MlpPolicy, CnnPolicy, ...)
:param env: The environment to learn from (if registered in Gym, can be str)
:param learning_rate: learning rate for adam optimizer,
the same learning rate will be used for all networks (Q-Values, Actor and Value function)
it can be a function of the current progress remaining (from 1 to 0)
:param buffer_size: size of the replay buffer
:param learning_starts: how many steps of the model to collect transitions for before learning starts
:param batch_size: Minibatch size for each gradient update
:param tau: the soft update coefficient ("Polyak update", between 0 and 1)
:param gamma: the discount factor
:param train_freq: Update the model every ``train_freq`` steps. Alternatively pass a tuple of frequency and unit
like ``(5, "step")`` or ``(2, "episode")``.
:param gradient_steps: How many gradient steps to do after each rollout (see ``train_freq``)
Set to ``-1`` means to do as many gradient steps as steps done in the environment
during the rollout.
:param action_noise: the action noise type (None by default), this can help
for hard exploration problem. Cf common.noise for the different action noise type.
:param replay_buffer_class: Replay buffer class to use (for instance ``HerReplayBuffer``).
If ``None``, it will be automatically selected.
:param replay_buffer_kwargs: Keyword arguments to pass to the replay buffer on creation.
:param optimize_memory_usage: Enable a memory efficient variant of the replay buffer
at a cost of more complexity.
See https://github.com/DLR-RM/stable-baselines3/issues/37#issuecomment-637501195
:param policy_delay: Policy and target networks will only be updated once every policy_delay steps
per training steps. The Q values will be updated policy_delay more often (update every training step).
:param target_policy_noise: Standard deviation of Gaussian noise added to target policy
(smoothing noise)
:param target_noise_clip: Limit for absolute value of target policy smoothing noise.
:param stats_window_size: Window size for the rollout logging, specifying the number of episodes to average
the reported success rate, mean episode length, and mean reward over
:param tensorboard_log: the log location for tensorboard (if None, no logging)
:param policy_kwargs: additional arguments to be passed to the policy on creation
:param verbose: Verbosity level: 0 for no output, 1 for info messages (such as device or wrappers used), 2 for
debug messages
:param seed: Seed for the pseudo random generators
:param device: Device (cpu, cuda, ...) on which the code should be run.
Setting it to auto, the code will be run on the GPU if possible.
:param _init_setup_model: Whether or not to build the network at the creation of the instance
"""
policy_aliases: ClassVar[Dict[str, Type[BasePolicy]]] = {
"MlpPolicy": MlpPolicy,
"CnnPolicy": CnnPolicy,
"MultiInputPolicy": MultiInputPolicy,
}
policy: TD3Policy
actor: Actor
actor_target: Actor
critic: ContinuousCritic
critic_target: ContinuousCritic
def __init__(
self,
policy: Union[str, Type[TD3Policy]],
env: Union[GymEnv, str],
learning_rate: Union[float, Schedule] = 1e-3,
buffer_size: int = 1_000_000, # 1e6
learning_starts: int = 100,
batch_size: int = 256,
tau: float = 0.005,
gamma: float = 0.99,
train_freq: Union[int, Tuple[int, str]] = 1,
gradient_steps: int = 1,
action_noise: Optional[ActionNoise] = None,
replay_buffer_class: Optional[Type[ReplayBuffer]] = None,
replay_buffer_kwargs: Optional[Dict[str, Any]] = None,
optimize_memory_usage: bool = False,
policy_delay: int = 2,
target_policy_noise: float = 0.2,
target_noise_clip: float = 0.5,
stats_window_size: int = 100,
tensorboard_log: Optional[str] = None,
policy_kwargs: Optional[Dict[str, Any]] = None,
verbose: int = 0,
seed: Optional[int] = None,
device: Union[th.device, str] = "auto",
_init_setup_model: bool = True,
):
super().__init__(
policy,
env,
learning_rate,
buffer_size,
learning_starts,
batch_size,
tau,
gamma,
train_freq,
gradient_steps,
action_noise=action_noise,
replay_buffer_class=replay_buffer_class,
replay_buffer_kwargs=replay_buffer_kwargs,
policy_kwargs=policy_kwargs,
stats_window_size=stats_window_size,
tensorboard_log=tensorboard_log,
verbose=verbose,
device=device,
seed=seed,
sde_support=False,
optimize_memory_usage=optimize_memory_usage,
supported_action_spaces=(spaces.Box,),
support_multi_env=True,
)
self.policy_delay = policy_delay
self.target_noise_clip = target_noise_clip
self.target_policy_noise = target_policy_noise
if _init_setup_model:
self._setup_model()
def _setup_model(self) -> None:
super()._setup_model()
self._create_aliases()
# Running mean and running var
self.actor_batch_norm_stats = get_parameters_by_name(self.actor, ["running_"])
self.critic_batch_norm_stats = get_parameters_by_name(self.critic, ["running_"])
self.actor_batch_norm_stats_target = get_parameters_by_name(self.actor_target, ["running_"])
self.critic_batch_norm_stats_target = get_parameters_by_name(self.critic_target, ["running_"])
def _create_aliases(self) -> None:
self.actor = self.policy.actor
self.actor_target = self.policy.actor_target
self.critic = self.policy.critic
self.critic_target = self.policy.critic_target
[docs] def train(self, gradient_steps: int, batch_size: int = 100) -> None:
# Switch to train mode (this affects batch norm / dropout)
self.policy.set_training_mode(True)
# Update learning rate according to lr schedule
self._update_learning_rate([self.actor.optimizer, self.critic.optimizer])
actor_losses, critic_losses = [], []
for _ in range(gradient_steps):
self._n_updates += 1
# Sample replay buffer
replay_data = self.replay_buffer.sample(batch_size, env=self._vec_normalize_env) # type: ignore[union-attr]
with th.no_grad():
# Select action according to policy and add clipped noise
noise = replay_data.actions.clone().data.normal_(0, self.target_policy_noise)
noise = noise.clamp(-self.target_noise_clip, self.target_noise_clip)
next_actions = (self.actor_target(replay_data.next_observations) + noise).clamp(-1, 1)
# Compute the next Q-values: min over all critics targets
next_q_values = th.cat(self.critic_target(replay_data.next_observations, next_actions), dim=1)
next_q_values, _ = th.min(next_q_values, dim=1, keepdim=True)
target_q_values = replay_data.rewards + (1 - replay_data.dones) * self.gamma * next_q_values
# Get current Q-values estimates for each critic network
current_q_values = self.critic(replay_data.observations, replay_data.actions)
# Compute critic loss
critic_loss = sum(F.mse_loss(current_q, target_q_values) for current_q in current_q_values)
assert isinstance(critic_loss, th.Tensor)
critic_losses.append(critic_loss.item())
# Optimize the critics
self.critic.optimizer.zero_grad()
critic_loss.backward()
self.critic.optimizer.step()
# Delayed policy updates
if self._n_updates % self.policy_delay == 0:
# Compute actor loss
actor_loss = -self.critic.q1_forward(replay_data.observations, self.actor(replay_data.observations)).mean()
actor_losses.append(actor_loss.item())
# Optimize the actor
self.actor.optimizer.zero_grad()
actor_loss.backward()
self.actor.optimizer.step()
polyak_update(self.critic.parameters(), self.critic_target.parameters(), self.tau)
polyak_update(self.actor.parameters(), self.actor_target.parameters(), self.tau)
# Copy running stats, see GH issue #996
polyak_update(self.critic_batch_norm_stats, self.critic_batch_norm_stats_target, 1.0)
polyak_update(self.actor_batch_norm_stats, self.actor_batch_norm_stats_target, 1.0)
self.logger.record("train/n_updates", self._n_updates, exclude="tensorboard")
if len(actor_losses) > 0:
self.logger.record("train/actor_loss", np.mean(actor_losses))
self.logger.record("train/critic_loss", np.mean(critic_losses))
[docs] def learn(
self: SelfTD3,
total_timesteps: int,
callback: MaybeCallback = None,
log_interval: int = 4,
tb_log_name: str = "TD3",
reset_num_timesteps: bool = True,
progress_bar: bool = False,
) -> SelfTD3:
return super().learn(
total_timesteps=total_timesteps,
callback=callback,
log_interval=log_interval,
tb_log_name=tb_log_name,
reset_num_timesteps=reset_num_timesteps,
progress_bar=progress_bar,
)
def _excluded_save_params(self) -> List[str]:
return super()._excluded_save_params() + ["actor", "critic", "actor_target", "critic_target"] # noqa: RUF005
def _get_torch_save_params(self) -> Tuple[List[str], List[str]]:
state_dicts = ["policy", "actor.optimizer", "critic.optimizer"]
return state_dicts, []