Python
Tensorflow + Keras + OpenAI Gym implementation of 1-step Q Learning from "Asynchronous Methods for Deep Reinforcement Learning"

Asyncronous RL in Tensorflow + Keras + OpenAI's Gym

This is a Tensorflow + Keras implementation of asyncronous 1-step Q learning as described in "Asynchronous Methods for Deep Reinforcement Learning".

Since we're using multiple actor-learner threads to stabilize learning in place of experience replay (which is super memory intensive), this runs comfortably on a macbook w/ 4g of ram.

It uses Keras to define the deep q network (see model.py), OpenAI's gym library to interact with the Atari Learning Environment (see atari_environment.py), and Tensorflow for optimization/execution (see async_dqn.py).

Usage

Training

To kick off training, run:

python async_dqn.py --experiment breakout --game "Breakout-v0" --num_concurrent 8

Here we're organizing the outputs for the current experiment under a folder called 'breakout', choosing "Breakout-v0" as our gym environment, and running 8 actor-learner threads concurrently.

Visualizing training with tensorboard

We collect episode reward stats and max q values that can be vizualized with tensorboard by running the following:

tensorboard --logdir /tmp/summaries/breakout

This is what my per-episode reward and average max q value curves looked like over the training period:

Evaluation

To run a gym evaluation, turn the testing flag to True and hand in a current checkpoint file:

python async_dqn.py --experiment breakout --testing True --checkpoint_path /tmp/breakout.ckpt-2690000 --num_eval_episodes 100

After completing the eval, we can upload our eval file to OpenAI's site as follows:

import gym
gym.upload('/tmp/breakout/eval', api_key='YOUR_API_KEY')

Now we can find the eval at https://gym.openai.com/evaluations/eval_uwwAN0U3SKSkocC0PJEwQ

Next Steps

See a3c.py for a WIP async advantage actor critic implementation.

Resources

I found these super helpful as general background materials for deep RL:

• David Silver's "Deep Reinforcement Learning" lecture
• Nervana's Demystifying Deep Reinforcement Learning blog post

Note

This has no affiliation with Deepmind or the authors, this is just a simple project I was using to learn TensorFlow. Feedback is highly appreciated.