Decoupled Reinforcement Learning to Stabilise Intrinsically-Motivated Exploration

This repository is the official implementation of Decoupled Reinforcement Learning (DeRL)

Dependencies

Clone and install codebase with relevant dependencies using the provided setup.py with

$ git clone git@github.com:uoe-agents/derl.git
$ cd derl
$ pip install -e .

We recommend to install dependencies in a virtual environment (tested with Python 3.7.12).

In order to run experiments in the Hallway environment, install using the following code:

$ cd hallway_explore
$ pip install -e .

Training

To train baselines or DeRL algorithms with the identified best hyperparameters, navigate to the derl directory

$ cd derl

and execute the script:

$ python run_best.py run --seeds=<NUM_SEEDS> <ENV> <ALG-CONFIG> <INTRINSIC_REWARD> start

Valid environments are

• deepsea_<N> for N in {10, 14, 20, 24, 30}
• hallway_<Nl>-<Nr> for Nl in {10, 20, 30} and Nr in {N_l, 0}

Valid algorithm configurations can be found in best_config:

• deepsea_a2c
• deepsea_ppo
• deepsea_dea2c
• deepsea_deppo
• deepsea_dedqn
• hallway_a2c
• hallway_ppo
• hallway_dea2c
• hallway_deppo
• hallway_dedqn

Valid intrinsic rewards for baseline configurations (A2C and PPO) are

• none: no intrinsic rewards
• dict_count: count-based intrinsic reward with a simple lookup table
• hash_count: count-based intrinsic reward with the SimHash hash-function used to group states (https://arxiv.org/abs/1611.04717)
• icm: prediction-based intrinsic reward of Intrinsic Curiosity Module (ICM) (https://arxiv.org/abs/1705.05363)
• rnd: prediction-based intrinsic reward of Random Network Distillation (RND) (https://arxiv.org/abs/1810.12894)
• ride: prediction-based intrinsic reward of Rewarding-Impact-Driven-Exploration (RIDE) (https://arxiv.org/abs/2002.12292)

For Decoupled RL algorithms (DeA2C, DePPO, DeDQN), valid intrinsic rewards are

• dict_count
• icm

Divergence Constraint Experiments

For experiments with divergence constraints, set the KL constraint coefficients $$\alpha_\beta$$ (corresponding to algorithm.kl_coef) and $$\alpha_e$$ (corresponding to exploitation_algorithm.kl_coef). For the respective DeA2C Dict-Count experiments presented in Section 7, run the following commands:

$ python3 run_best.py run --seeds=3 deepsea_10 deepsea_dea2c_kl dict_count start
$ python3 run_best.py run --seeds=3 hallway_20-20 hallway_dea2c_kl dict_count start

Codebase Structure

Hydra Configurations

The interface of the main run script run.py is handled through Hydra with a hierarchy of configuration files under configs/. These are structured in packages for

• exploration algorithms/ baselines under configs/algorithm/
• intrinsic rewards under configs/curiosity/
• environments under configs/env/
• exploitation algorithms of DeRL under configs/exploitation_algorithm/
• hydra parameters under configs/hydra/
• logger parameters under configs/logger/
• default parameters in configs/default.yaml

On-Policy Algorithms

Two on-policy algorithms are implemented under on_policy/ which extend the abstract algorithm class found in on_policy/algorithm.py:

• Advantage Actor-Critic (A2C) found in on_policy/algos/a2c.py
• Proximal Policy Optimisation (PPO) found in on_policy/algos/ppo.py

Shared elements such as network models, on-policy storage etc. can be found in on_policy/common/ and the training script for on-policy algorithms can be found in on_policy/train.py.

Off-Policy Algorithms

For off-policy RL algorithms, only (Double) Deep Q-Networks (DQNs) are implemented under off_policy/ which extend the abstract algorithm class found in off_policy/algorithm.py. The (D)DQN implementation can be found in off_policy/algos/dqn.py. Common components such as network models, prioritised and standard replay buffers can be found under off_policy/common/ and the training script for off-policy algorithms can be found in off_policy/train.py.

DISCLAIMER: Training of off-policy DQN for the exploration policy or baseline is implemented but has not been extensively tested nor evaluated for the paper.

Intrinsic Rewards

We consider five different definitions of count- and prediction-based intrinsic rewards for exploration. Their implementations can all be found under intrinsic_rewards/ and extend the abstract base class found in intrinsic_rewards/intrinsic_reward.py which serves as a common interface.

Utils

Further utilities such as environment wrappers/ setup, loggers and more can be found under utils/.

Citation

@inproceedings{schaefer2022derl,
	title={Decoupled Reinforcement Learning to Stabilise Intrinsically-Motivated Exploration},
	author={Lukas Schäfer and Filippos Christianos and Josiah P. Hanna and Stefano V. Albrecht},
	booktitle={International Conference on Autonomous Agents and Multiagent Systems},
	year={2022}
}