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SAC

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SAC(
   env: VecEnv, eval_env: Optional[VecEnv] = None, tag: str = 'default', seed: int = 1,
   device: str = 'cpu', pretraining: bool = False, num_init_steps: int = 5000,
   storage_size: int = 10000000, feature_dim: int = 50, batch_size: int = 1024,
   lr: float = 0.0001, eps: float = 1e-08, hidden_dim: int = 1024,
   actor_update_freq: int = 1, critic_target_tau: float = 0.005,
   critic_target_update_freq: int = 2, log_std_range: Tuple[float, ...] = (-5.0, 2),
   betas: Tuple[float, float] = (0.9, 0.999), temperature: float = 0.1,
   fixed_temperature: bool = False, discount: float = 0.99, init_fn: str = 'orthogonal'
)

Soft Actor-Critic (SAC) agent. Based on: https://github.com/denisyarats/pytorch_sac

Args

  • env (VecEnv) : Vectorized environments for training.
  • eval_env (VecEnv) : Vectorized environments for evaluation.
  • tag (str) : An experiment tag.
  • seed (int) : Random seed for reproduction.
  • device (str) : Device (cpu, cuda, ...) on which the code should be run.
  • pretraining (bool) : Turn on the pre-training mode.
  • num_init_steps (int) : Number of initial exploration steps.
  • storage_size (int) : The capacity of the storage.
  • feature_dim (int) : Number of features extracted by the encoder.
  • batch_size (int) : Number of samples per batch to load.
  • lr (float) : The learning rate.
  • eps (float) : Term added to the denominator to improve numerical stability.
  • hidden_dim (int) : The size of the hidden layers.
  • actor_update_freq (int) : The actor update frequency (in steps).
  • critic_target_tau (float) : The critic Q-function soft-update rate.
  • critic_target_update_freq (int) : The critic Q-function soft-update frequency (in steps).
  • log_std_range (Tuple[float]) : Range of std for sampling actions.
  • betas (Tuple[float]) : Coefficients used for computing running averages of gradient and its square.
  • temperature (float) : Initial temperature coefficient.
  • fixed_temperature (bool) : Fixed temperature or not.
  • discount (float) : Discount factor.
  • init_fn (str) : Parameters initialization method.

Returns

PPO agent instance.

Methods:

.alpha

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.alpha()

Get the temperature coefficient.

.update

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.update()

Update the agent and return training metrics such as actor loss, critic_loss, etc.

.update_critic

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.update_critic(
   obs: th.Tensor, actions: th.Tensor, rewards: th.Tensor, terminateds: th.Tensor,
   truncateds: th.Tensor, next_obs: th.Tensor
)

Update the critic network.

Args

  • obs (th.Tensor) : Observations.
  • actions (th.Tensor) : Actions.
  • rewards (th.Tensor) : Rewards.
  • terminateds (th.Tensor) : Terminateds.
  • truncateds (th.Tensor) : Truncateds.
  • next_obs (th.Tensor) : Next observations.

Returns

None.

.update_actor_and_alpha

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.update_actor_and_alpha(
   obs: th.Tensor
)

Update the actor network and temperature.

Args

  • obs (th.Tensor) : Observations.

Returns

None.