Source code for sb3_contrib.qrdqn.qrdqn

from typing import Any, Dict, List, Optional, Tuple, Type, Union

import gym
import numpy as np
import torch as th
from stable_baselines3.common import logger
from stable_baselines3.common.off_policy_algorithm import OffPolicyAlgorithm
from stable_baselines3.common.preprocessing import maybe_transpose
from stable_baselines3.common.type_aliases import GymEnv, MaybeCallback, Schedule
from stable_baselines3.common.utils import get_linear_fn, is_vectorized_observation, polyak_update

from sb3_contrib.common.utils import quantile_huber_loss
from sb3_contrib.qrdqn.policies import QRDQNPolicy

[docs]class QRDQN(OffPolicyAlgorithm): """ Quantile Regression Deep Q-Network (QR-DQN) Paper: Default hyperparameters are taken from the paper and are tuned for Atari games. :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: The learning rate, 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) default 1 for hard update :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`` and ``n_episodes_rollout``) Set to ``-1`` means to do as many gradient steps as steps done in the environment during the rollout. :param optimize_memory_usage: Enable a memory efficient variant of the replay buffer at a cost of more complexity. See :param target_update_interval: update the target network every ``target_update_interval`` environment steps. :param exploration_fraction: fraction of entire training period over which the exploration rate is reduced :param exploration_initial_eps: initial value of random action probability :param exploration_final_eps: final value of random action probability :param max_grad_norm: The maximum value for the gradient clipping (if None, no clipping) :param tensorboard_log: the log location for tensorboard (if None, no logging) :param create_eval_env: Whether to create a second environment that will be used for evaluating the agent periodically. (Only available when passing string for the environment) :param policy_kwargs: additional arguments to be passed to the policy on creation :param verbose: the verbosity level: 0 no output, 1 info, 2 debug :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 """ def __init__( self, policy: Union[str, Type[QRDQNPolicy]], env: Union[GymEnv, str], learning_rate: Union[float, Schedule] = 5e-5, buffer_size: int = 1000000, learning_starts: int = 50000, batch_size: Optional[int] = 32, tau: float = 1.0, gamma: float = 0.99, train_freq: int = 4, gradient_steps: int = 1, optimize_memory_usage: bool = False, target_update_interval: int = 10000, exploration_fraction: float = 0.005, exploration_initial_eps: float = 1.0, exploration_final_eps: float = 0.01, max_grad_norm: Optional[float] = None, tensorboard_log: Optional[str] = None, create_eval_env: bool = False, 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(QRDQN, self).__init__( policy, env, QRDQNPolicy, learning_rate, buffer_size, learning_starts, batch_size, tau, gamma, train_freq, gradient_steps, action_noise=None, # No action noise policy_kwargs=policy_kwargs, tensorboard_log=tensorboard_log, verbose=verbose, device=device, create_eval_env=create_eval_env, seed=seed, sde_support=False, optimize_memory_usage=optimize_memory_usage, supported_action_spaces=(gym.spaces.Discrete,), ) self.exploration_initial_eps = exploration_initial_eps self.exploration_final_eps = exploration_final_eps self.exploration_fraction = exploration_fraction self.target_update_interval = target_update_interval self.max_grad_norm = max_grad_norm # "epsilon" for the epsilon-greedy exploration self.exploration_rate = 0.0 # Linear schedule will be defined in `_setup_model()` self.exploration_schedule = None self.quantile_net, self.quantile_net_target = None, None if "optimizer_class" not in self.policy_kwargs: self.policy_kwargs["optimizer_class"] = th.optim.Adam # Proposed in the QR-DQN paper where `batch_size = 32` self.policy_kwargs["optimizer_kwargs"] = dict(eps=0.01 / batch_size) if _init_setup_model: self._setup_model() def _setup_model(self) -> None: super(QRDQN, self)._setup_model() self._create_aliases() self.exploration_schedule = get_linear_fn( self.exploration_initial_eps, self.exploration_final_eps, self.exploration_fraction ) def _create_aliases(self) -> None: self.quantile_net = self.policy.quantile_net self.quantile_net_target = self.policy.quantile_net_target self.n_quantiles = self.policy.n_quantiles def _on_step(self) -> None: """ Update the exploration rate and target network if needed. This method is called in ``collect_rollouts()`` after each step in the environment. """ if self.num_timesteps % self.target_update_interval == 0: polyak_update(self.quantile_net.parameters(), self.quantile_net_target.parameters(), self.tau) self.exploration_rate = self.exploration_schedule(self._current_progress_remaining) logger.record("rollout/exploration rate", self.exploration_rate)
[docs] def train(self, gradient_steps: int, batch_size: int = 100) -> None: # Update learning rate according to schedule self._update_learning_rate(self.policy.optimizer) losses = [] for gradient_step in range(gradient_steps): # Sample replay buffer replay_data = self.replay_buffer.sample(batch_size, env=self._vec_normalize_env) with th.no_grad(): # Compute the quantiles of next observation next_quantiles = self.quantile_net_target(replay_data.next_observations) # Compute the greedy actions which maximize the next Q values next_greedy_actions = next_quantiles.mean(dim=1, keepdim=True).argmax(dim=2, keepdim=True) # Make "n_quantiles" copies of actions, and reshape to (batch_size, n_quantiles, 1) next_greedy_actions = next_greedy_actions.expand(batch_size, self.n_quantiles, 1) # Follow greedy policy: use the one with the highest Q values next_quantiles = next_quantiles.gather(dim=2, index=next_greedy_actions).squeeze(dim=2) # 1-step TD target target_quantiles = replay_data.rewards + (1 - replay_data.dones) * self.gamma * next_quantiles # Get current quantile estimates current_quantiles = self.quantile_net(replay_data.observations) # Make "n_quantiles" copies of actions, and reshape to (batch_size, n_quantiles, 1). actions = replay_data.actions[..., None].long().expand(batch_size, self.n_quantiles, 1) # Retrieve the quantiles for the actions from the replay buffer current_quantiles = th.gather(current_quantiles, dim=2, index=actions).squeeze(dim=2) # Compute Quantile Huber loss, summing over a quantile dimension as in the paper. loss = quantile_huber_loss(current_quantiles, target_quantiles, sum_over_quantiles=True) losses.append(loss.item()) # Optimize the policy self.policy.optimizer.zero_grad() loss.backward() # Clip gradient norm if self.max_grad_norm is not None: th.nn.utils.clip_grad_norm_(self.policy.parameters(), self.max_grad_norm) self.policy.optimizer.step() # Increase update counter self._n_updates += gradient_steps logger.record("train/n_updates", self._n_updates, exclude="tensorboard") logger.record("train/loss", np.mean(losses))
[docs] def predict( self, observation: np.ndarray, state: Optional[np.ndarray] = None, mask: Optional[np.ndarray] = None, deterministic: bool = False, ) -> Tuple[np.ndarray, Optional[np.ndarray]]: """ Overrides the base_class predict function to include epsilon-greedy exploration. :param observation: the input observation :param state: The last states (can be None, used in recurrent policies) :param mask: The last masks (can be None, used in recurrent policies) :param deterministic: Whether or not to return deterministic actions. :return: the model's action and the next state (used in recurrent policies) """ if not deterministic and np.random.rand() < self.exploration_rate: if is_vectorized_observation(maybe_transpose(observation, self.observation_space), self.observation_space): n_batch = observation.shape[0] action = np.array([self.action_space.sample() for _ in range(n_batch)]) else: action = np.array(self.action_space.sample()) else: action, state = self.policy.predict(observation, state, mask, deterministic) return action, state
[docs] def learn( self, total_timesteps: int, callback: MaybeCallback = None, log_interval: int = 4, eval_env: Optional[GymEnv] = None, eval_freq: int = -1, n_eval_episodes: int = 5, tb_log_name: str = "QRDQN", eval_log_path: Optional[str] = None, reset_num_timesteps: bool = True, ) -> OffPolicyAlgorithm: return super(QRDQN, self).learn( total_timesteps=total_timesteps, callback=callback, log_interval=log_interval, eval_env=eval_env, eval_freq=eval_freq, n_eval_episodes=n_eval_episodes, tb_log_name=tb_log_name, eval_log_path=eval_log_path, reset_num_timesteps=reset_num_timesteps, )
def _excluded_save_params(self) -> List[str]: return super(QRDQN, self)._excluded_save_params() + ["quantile_net", "quantile_net_target"] def _get_torch_save_params(self) -> Tuple[List[str], List[str]]: state_dicts = ["policy", "policy.optimizer"] return state_dicts, []