The goal of this repo is to train two agents in the form of tenis rackets and mantain the ball in play as longer as possible. i.e. The goal of each agent is to keep the ball in play.

The below illustration shows the final outcome of the current solution that uses a multi agent actor-critic method to solve the problem.

The observation space consists of 24 variables corresponding to the position and velocity of the ball and racket. Each agent receives its own, local observation. Two continuous actions are available, corresponding to movement toward (or away from) the net, and jumping.

• Continuous state space: 24
• Continuous action space: 2
• number of agents: 2

The task is episodic, and in order to solve the environment, your agents must get an average score of +0.5 (over 100 consecutive episodes, after taking the maximum over both agents). Specifically,

• After each episode, we add up the rewards that each agent received (without discounting), to get a score for each agent. This yields 2 (potentially different) scores. We then take the maximum of these 2 scores.
• This yields a single score for each episode.

The environment is considered solved, when the average (over 100 episodes) of those scores is at least +0.5.

For more details on the project solution please read the report.md file.

All commands below must be run in the project's folder cd <path_to_root_folder_of_this_project>

• Make sure to download the environment builded in unity with ml_agents extension

  For linux:

  • Two-racket tennis scenario from mlagents. You can find the binaries here

For this project a docker container was created, please follow the following steps to setup the environment:

1. Build Dockerfile

   docker build -t unity_ml_agents:pytorch .

2. Create container (this assumes you want to run the project on GPU)

   docker run --name mlagents_unity -v /tmp/.X11-unix:/tmp/.X11-unix -e DISPLAY=$DISPLAY -v `pwd`:/project -it --env QT_X11_NO_MITSHM=1 --device /dev/dri --privileged --gpus all unity_ml_agents:pytorch

3. Everytime we want to run container

   docker start mlagents_unity

   docker exec -it mlagents_unity bash

The main script is in the tennis.ipynb file, where you can run a dummy model that selects and action randomly. You can also train a MADDPG model with 2 agents and use it in inference of new cases.

If you want to check the agents model you can find it under the folder: agents/maddpg/. In this folder the main logic for the agent models is implemented in the maddpg.py.

• actor_critic_models.py constains the two neural networks used to build the ddpg agent
• ddpg_agent.py constains the code to build a ddpg agent. This script is used by the maddpg for creating multiple ddpg agents.
• helpers.py constains all maddpg helper funtions that assist maddpg logic such as the replay buffer and the Ornstein-Uhlenbeck noise.
• Finally the parameters.py script constains all the parameters that could be changed in this project. If you are interested in trying different training processes this is the file you are looking for.