TQC

Controlling Overestimation Bias with Truncated Mixture of Continuous Distributional Quantile Critics (TQC). Truncated Quantile Critics (TQC) builds on SAC, TD3 and QR-DQN, making use of quantile regression to predict a distribution for the value function (instead of a mean value). It truncates the quantiles predicted by different networks (a bit as it is done in TD3).

Available Policies

MlpPolicy

alias of TQCPolicy

CnnPolicy

Policy class (with both actor and critic) for TQC.

MultiInputPolicy

Policy class (with both actor and critic) for TQC.

Notes

Can I use?

  • Recurrent policies: ❌

  • Multi processing: ✔️

  • Gym spaces:

Space

Action

Observation

Discrete

✔️

Box

✔️

✔️

MultiDiscrete

✔️

MultiBinary

✔️

Dict

✔️

Example

import gym
import numpy as np

from sb3_contrib import TQC

env = gym.make("Pendulum-v1")

policy_kwargs = dict(n_critics=2, n_quantiles=25)
model = TQC("MlpPolicy", env, top_quantiles_to_drop_per_net=2, verbose=1, policy_kwargs=policy_kwargs)
model.learn(total_timesteps=10000, log_interval=4)
model.save("tqc_pendulum")

del model # remove to demonstrate saving and loading

model = TQC.load("tqc_pendulum")

obs = env.reset()
while True:
    action, _states = model.predict(obs, deterministic=True)
    obs, reward, done, info = env.step(action)
    env.render()
    if done:
      obs = env.reset()

Results

Result on the PyBullet benchmark (1M steps) and on BipedalWalkerHardcore-v3 (2M steps) using 3 seeds. The complete learning curves are available in the associated PR.

The main difference with SAC is on harder environments (BipedalWalkerHardcore, Walker2D).

Note

Hyperparameters from the gSDE paper were used (as they are tuned for SAC on PyBullet envs), including using gSDE for the exploration and not the unstructured Gaussian noise but this should not affect results in simulation.

Note

We are using the open source PyBullet environments and not the MuJoCo simulator (as done in the original paper). You can find a complete benchmark on PyBullet envs in the gSDE paper if you want to compare TQC results to those of A2C/PPO/SAC/TD3.

Environments

SAC

TQC

gSDE

gSDE

HalfCheetah

2984 +/- 202

3041 +/- 157

Ant

3102 +/- 37

3700 +/- 37

Hopper

2262 +/- 1

2401 +/- 62*

Walker2D

2136 +/- 67

2535 +/- 94

BipedalWalkerHardcore

13 +/- 18

228 +/- 18

* with tuned hyperparameter top_quantiles_to_drop_per_net taken from the original paper

How to replicate the results?

Clone RL-Zoo and checkout the branch feat/tqc:

git clone https://github.com/DLR-RM/rl-baselines3-zoo
cd rl-baselines3-zoo/
git checkout feat/tqc

Run the benchmark (replace $ENV_ID by the envs mentioned above):

python train.py --algo tqc --env $ENV_ID --eval-episodes 10 --eval-freq 10000

Plot the results:

python scripts/all_plots.py -a tqc -e HalfCheetah Ant Hopper Walker2D BipedalWalkerHardcore -f logs/ -o logs/tqc_results
python scripts/plot_from_file.py -i logs/tqc_results.pkl -latex -l TQC

Comments

This implementation is based on SB3 SAC implementation and uses the code from the original TQC implementation for the quantile huber loss.

Parameters

class sb3_contrib.tqc.TQC(policy, env, learning_rate=0.0003, buffer_size=1000000, learning_starts=100, batch_size=256, tau=0.005, gamma=0.99, train_freq=1, gradient_steps=1, action_noise=None, replay_buffer_class=None, replay_buffer_kwargs=None, optimize_memory_usage=False, ent_coef='auto', target_update_interval=1, target_entropy='auto', top_quantiles_to_drop_per_net=2, use_sde=False, sde_sample_freq=- 1, use_sde_at_warmup=False, tensorboard_log=None, create_eval_env=False, policy_kwargs=None, verbose=0, seed=None, device='auto', _init_setup_model=True)[source]

Controlling Overestimation Bias with Truncated Mixture of Continuous Distributional Quantile Critics. Paper: https://arxiv.org/abs/2005.04269 This implementation uses SB3 SAC implementation as base.

Parameters
  • policy (Union[str, Type[TQCPolicy]]) – The policy model to use (MlpPolicy, CnnPolicy, …)

  • env (Union[Env, VecEnv, str]) – The environment to learn from (if registered in Gym, can be str)

  • learning_rate (Union[float, Callable]) – 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)

  • buffer_size (int) – size of the replay buffer

  • learning_starts (int) – how many steps of the model to collect transitions for before learning starts

  • batch_size (int) – Minibatch size for each gradient update

  • tau (float) – the soft update coefficient (“Polyak update”, between 0 and 1)

  • gamma (float) – the discount factor

  • train_freq (int) – Update the model every train_freq steps. Alternatively pass a tuple of frequency and unit like (5, "step") or (2, "episode").

  • gradient_steps (int) – How many gradient update after each step

  • action_noise (Optional[ActionNoise]) – the action noise type (None by default), this can help for hard exploration problem. Cf common.noise for the different action noise type.

  • replay_buffer_class (Optional[ReplayBuffer]) – Replay buffer class to use (for instance HerReplayBuffer). If None, it will be automatically selected.

  • replay_buffer_kwargs (Optional[Dict[str, Any]]) – Keyword arguments to pass to the replay buffer on creation.

  • optimize_memory_usage (bool) – 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

  • ent_coef (Union[str, float]) – Entropy regularization coefficient. (Equivalent to inverse of reward scale in the original SAC paper.) Controlling exploration/exploitation trade-off. Set it to ‘auto’ to learn it automatically (and ‘auto_0.1’ for using 0.1 as initial value)

  • target_update_interval (int) – update the target network every target_network_update_freq gradient steps.

  • target_entropy (Union[str, float]) – target entropy when learning ent_coef (ent_coef = 'auto')

  • top_quantiles_to_drop_per_net (int) – Number of quantiles to drop per network

  • use_sde (bool) – Whether to use generalized State Dependent Exploration (gSDE) instead of action noise exploration (default: False)

  • sde_sample_freq (int) – Sample a new noise matrix every n steps when using gSDE Default: -1 (only sample at the beginning of the rollout)

  • use_sde_at_warmup (bool) – Whether to use gSDE instead of uniform sampling during the warm up phase (before learning starts)

  • create_eval_env (bool) – Whether to create a second environment that will be used for evaluating the agent periodically. (Only available when passing string for the environment)

  • policy_kwargs (Optional[Dict[str, Any]]) – additional arguments to be passed to the policy on creation

  • verbose (int) – the verbosity level: 0 no output, 1 info, 2 debug

  • seed (Optional[int]) – Seed for the pseudo random generators

  • device (Union[device, str]) – Device (cpu, cuda, …) on which the code should be run. Setting it to auto, the code will be run on the GPU if possible.

  • _init_setup_model (bool) – Whether or not to build the network at the creation of the instance

collect_rollouts(env, callback, train_freq, replay_buffer, action_noise=None, learning_starts=0, log_interval=None)

Collect experiences and store them into a ReplayBuffer.

Parameters
  • env (VecEnv) – The training environment

  • callback (BaseCallback) – Callback that will be called at each step (and at the beginning and end of the rollout)

  • train_freq (TrainFreq) – How much experience to collect by doing rollouts of current policy. Either TrainFreq(<n>, TrainFrequencyUnit.STEP) or TrainFreq(<n>, TrainFrequencyUnit.EPISODE) with <n> being an integer greater than 0.

  • action_noise (Optional[ActionNoise]) – Action noise that will be used for exploration Required for deterministic policy (e.g. TD3). This can also be used in addition to the stochastic policy for SAC.

  • learning_starts (int) – Number of steps before learning for the warm-up phase.

  • replay_buffer (ReplayBuffer) –

  • log_interval (Optional[int]) – Log data every log_interval episodes

Return type

RolloutReturn

Returns

get_env()

Returns the current environment (can be None if not defined).

Return type

Optional[VecEnv]

Returns

The current environment

get_parameters()

Return the parameters of the agent. This includes parameters from different networks, e.g. critics (value functions) and policies (pi functions).

Return type

Dict[str, Dict]

Returns

Mapping of from names of the objects to PyTorch state-dicts.

get_vec_normalize_env()

Return the VecNormalize wrapper of the training env if it exists.

Return type

Optional[VecNormalize]

Returns

The VecNormalize env.

learn(total_timesteps, callback=None, log_interval=4, eval_env=None, eval_freq=- 1, n_eval_episodes=5, tb_log_name='TQC', eval_log_path=None, reset_num_timesteps=True)[source]

Return a trained model.

Parameters
  • total_timesteps (int) – The total number of samples (env steps) to train on

  • callback (Union[None, Callable, List[BaseCallback], BaseCallback]) – callback(s) called at every step with state of the algorithm.

  • log_interval (int) – The number of timesteps before logging.

  • tb_log_name (str) – the name of the run for TensorBoard logging

  • eval_env (Union[Env, VecEnv, None]) – Environment that will be used to evaluate the agent

  • eval_freq (int) – Evaluate the agent every eval_freq timesteps (this may vary a little)

  • n_eval_episodes (int) – Number of episode to evaluate the agent

  • eval_log_path (Optional[str]) – Path to a folder where the evaluations will be saved

  • reset_num_timesteps (bool) – whether or not to reset the current timestep number (used in logging)

Return type

OffPolicyAlgorithm

Returns

the trained model

classmethod load(path, env=None, device='auto', custom_objects=None, print_system_info=False, force_reset=True, **kwargs)

Load the model from a zip-file. Warning: load re-creates the model from scratch, it does not update it in-place! For an in-place load use set_parameters instead.

Parameters
  • path (Union[str, Path, BufferedIOBase]) – path to the file (or a file-like) where to load the agent from

  • env (Union[Env, VecEnv, None]) – the new environment to run the loaded model on (can be None if you only need prediction from a trained model) has priority over any saved environment

  • device (Union[device, str]) – Device on which the code should run.

  • custom_objects (Optional[Dict[str, Any]]) – Dictionary of objects to replace upon loading. If a variable is present in this dictionary as a key, it will not be deserialized and the corresponding item will be used instead. Similar to custom_objects in keras.models.load_model. Useful when you have an object in file that can not be deserialized.

  • print_system_info (bool) – Whether to print system info from the saved model and the current system info (useful to debug loading issues)

  • force_reset (bool) – Force call to reset() before training to avoid unexpected behavior. See https://github.com/DLR-RM/stable-baselines3/issues/597

  • kwargs – extra arguments to change the model when loading

Return type

BaseAlgorithm

Returns

new model instance with loaded parameters

load_replay_buffer(path, truncate_last_traj=True)

Load a replay buffer from a pickle file.

Parameters
  • path (Union[str, Path, BufferedIOBase]) – Path to the pickled replay buffer.

  • truncate_last_traj (bool) – When using HerReplayBuffer with online sampling: If set to True, we assume that the last trajectory in the replay buffer was finished (and truncate it). If set to False, we assume that we continue the same trajectory (same episode).

Return type

None

property logger: Logger

Getter for the logger object.

Return type

Logger

predict(observation, state=None, episode_start=None, deterministic=False)

Get the policy action from an observation (and optional hidden state). Includes sugar-coating to handle different observations (e.g. normalizing images).

Parameters
  • observation (ndarray) – the input observation

  • state (Optional[Tuple[ndarray, ...]]) – The last hidden states (can be None, used in recurrent policies)

  • episode_start (Optional[ndarray]) – The last masks (can be None, used in recurrent policies) this correspond to beginning of episodes, where the hidden states of the RNN must be reset.

  • deterministic (bool) – Whether or not to return deterministic actions.

Return type

Tuple[ndarray, Optional[Tuple[ndarray, ...]]]

Returns

the model’s action and the next hidden state (used in recurrent policies)

save(path, exclude=None, include=None)

Save all the attributes of the object and the model parameters in a zip-file.

Parameters
  • path (Union[str, Path, BufferedIOBase]) – path to the file where the rl agent should be saved

  • exclude (Optional[Iterable[str]]) – name of parameters that should be excluded in addition to the default ones

  • include (Optional[Iterable[str]]) – name of parameters that might be excluded but should be included anyway

Return type

None

save_replay_buffer(path)

Save the replay buffer as a pickle file.

Parameters

path (Union[str, Path, BufferedIOBase]) – Path to the file where the replay buffer should be saved. if path is a str or pathlib.Path, the path is automatically created if necessary.

Return type

None

set_env(env, force_reset=True)

Checks the validity of the environment, and if it is coherent, set it as the current environment. Furthermore wrap any non vectorized env into a vectorized checked parameters: - observation_space - action_space

Parameters
Return type

None

set_logger(logger)

Setter for for logger object.

Warning

When passing a custom logger object, this will overwrite tensorboard_log and verbose settings passed to the constructor.

Return type

None

set_parameters(load_path_or_dict, exact_match=True, device='auto')

Load parameters from a given zip-file or a nested dictionary containing parameters for different modules (see get_parameters).

Parameters
  • load_path_or_iter – Location of the saved data (path or file-like, see save), or a nested dictionary containing nn.Module parameters used by the policy. The dictionary maps object names to a state-dictionary returned by torch.nn.Module.state_dict().

  • exact_match (bool) – If True, the given parameters should include parameters for each module and each of their parameters, otherwise raises an Exception. If set to False, this can be used to update only specific parameters.

  • device (Union[device, str]) – Device on which the code should run.

Return type

None

set_random_seed(seed=None)

Set the seed of the pseudo-random generators (python, numpy, pytorch, gym, action_space)

Parameters

seed (Optional[int]) –

Return type

None

train(gradient_steps, batch_size=64)[source]

Sample the replay buffer and do the updates (gradient descent and update target networks)

Return type

None

TQC Policies

sb3_contrib.tqc.MlpPolicy

alias of TQCPolicy

class sb3_contrib.tqc.policies.TQCPolicy(observation_space, action_space, lr_schedule, net_arch=None, activation_fn=<class 'torch.nn.modules.activation.ReLU'>, use_sde=False, log_std_init=-3, sde_net_arch=None, use_expln=False, clip_mean=2.0, features_extractor_class=<class 'stable_baselines3.common.torch_layers.FlattenExtractor'>, features_extractor_kwargs=None, normalize_images=True, optimizer_class=<class 'torch.optim.adam.Adam'>, optimizer_kwargs=None, n_quantiles=25, n_critics=2, share_features_extractor=False)[source]

Policy class (with both actor and critic) for TQC.

Parameters
  • observation_space (Space) – Observation space

  • action_space (Space) – Action space

  • lr_schedule (Callable[[float], float]) – Learning rate schedule (could be constant)

  • net_arch (Union[List[int], Dict[str, List[int]], None]) – The specification of the policy and value networks.

  • activation_fn (Type[Module]) – Activation function

  • use_sde (bool) – Whether to use State Dependent Exploration or not

  • log_std_init (float) – Initial value for the log standard deviation

  • sde_net_arch (Optional[List[int]]) – Network architecture for extracting features when using gSDE. If None, the latent features from the policy will be used. Pass an empty list to use the states as features.

  • use_expln (bool) – Use expln() function instead of exp() when using gSDE to ensure a positive standard deviation (cf paper). It allows to keep variance above zero and prevent it from growing too fast. In practice, exp() is usually enough.

  • clip_mean (float) – Clip the mean output when using gSDE to avoid numerical instability.

  • features_extractor_class (Type[BaseFeaturesExtractor]) – Features extractor to use.

  • features_extractor_kwargs (Optional[Dict[str, Any]]) – Keyword arguments to pass to the feature extractor.

  • normalize_images (bool) – Whether to normalize images or not, dividing by 255.0 (True by default)

  • optimizer_class (Type[Optimizer]) – The optimizer to use, th.optim.Adam by default

  • optimizer_kwargs (Optional[Dict[str, Any]]) – Additional keyword arguments, excluding the learning rate, to pass to the optimizer

  • n_quantiles (int) – Number of quantiles for the critic.

  • n_critics (int) – Number of critic networks to create.

  • share_features_extractor (bool) – Whether to share or not the features extractor between the actor and the critic (this saves computation time)

forward(obs, deterministic=False)[source]

Defines the computation performed at every call.

Should be overridden by all subclasses.

Note

Although the recipe for forward pass needs to be defined within this function, one should call the Module instance afterwards instead of this since the former takes care of running the registered hooks while the latter silently ignores them.

Return type

Tensor

reset_noise(batch_size=1)[source]

Sample new weights for the exploration matrix, when using gSDE.

Parameters

batch_size (int) –

Return type

None

set_training_mode(mode)[source]

Put the policy in either training or evaluation mode. This affects certain modules, such as batch normalisation and dropout. :type mode: bool :param mode: if true, set to training mode, else set to evaluation mode

Return type

None

class sb3_contrib.tqc.CnnPolicy(observation_space, action_space, lr_schedule, net_arch=None, activation_fn=<class 'torch.nn.modules.activation.ReLU'>, use_sde=False, log_std_init=-3, sde_net_arch=None, use_expln=False, clip_mean=2.0, features_extractor_class=<class 'stable_baselines3.common.torch_layers.NatureCNN'>, features_extractor_kwargs=None, normalize_images=True, optimizer_class=<class 'torch.optim.adam.Adam'>, optimizer_kwargs=None, n_quantiles=25, n_critics=2, share_features_extractor=False)[source]

Policy class (with both actor and critic) for TQC.

Parameters
  • observation_space (Space) – Observation space

  • action_space (Space) – Action space

  • lr_schedule (Callable[[float], float]) – Learning rate schedule (could be constant)

  • net_arch (Union[List[int], Dict[str, List[int]], None]) – The specification of the policy and value networks.

  • activation_fn (Type[Module]) – Activation function

  • use_sde (bool) – Whether to use State Dependent Exploration or not

  • log_std_init (float) – Initial value for the log standard deviation

  • sde_net_arch (Optional[List[int]]) – Network architecture for extracting features when using gSDE. If None, the latent features from the policy will be used. Pass an empty list to use the states as features.

  • use_expln (bool) – Use expln() function instead of exp() when using gSDE to ensure a positive standard deviation (cf paper). It allows to keep variance above zero and prevent it from growing too fast. In practice, exp() is usually enough.

  • clip_mean (float) – Clip the mean output when using gSDE to avoid numerical instability.

  • features_extractor_class (Type[BaseFeaturesExtractor]) – Features extractor to use.

  • normalize_images (bool) – Whether to normalize images or not, dividing by 255.0 (True by default)

  • optimizer_class (Type[Optimizer]) – The optimizer to use, th.optim.Adam by default

  • optimizer_kwargs (Optional[Dict[str, Any]]) – Additional keyword arguments, excluding the learning rate, to pass to the optimizer

  • n_quantiles (int) – Number of quantiles for the critic.

  • n_critics (int) – Number of critic networks to create.

  • share_features_extractor (bool) – Whether to share or not the features extractor between the actor and the critic (this saves computation time)