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

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-v0")

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

TQC Policies