This repository contains various implementation of DQNs, with a number of additional tricks that have been propsed since then:

1. Human-Level Control Through Deep Reinforcement Learning - Volodymyr Mnih, Koray Kavukcuoglu, David Silver, Andrei A. Rusu, Joel Veness, Marc G. Bellemare, Alex Graves, Martin Riedmiller, Andreas K. Fidjeland, Georg Ostrovski, Stig Petersen, Charles Beattie, Amir Sadik, Ioannis Antonoglou, Helen King, Dharshan Kumaran, Daan Wierstra, Shane Legg & Demis Hassabis
2. Deep Reinforcement Learning with Double Q-learning - Hado van Hasselt and Arthur Guez and David Silver
3. Dueling Network Architectures for Deep Reinforcement Learning - Ziyu Wang and Tom Schaul and Matteo Hessel and Hado van Hasselt and Marc Lanctot and Nando de Freitas

I have applied these DQNs to various OpenAI Gym environments, and one Unity ML Agents environment.

These are the results (before and after GIFs) for the experiments that I have run.

Banana Collector (DQN)
Before Training	After Training

Lunar Lander v2 (DQN)
Before Training	After Training

Cart Pole v1 (Dueling DQN)
Before Training	After Training

This setup was done on a system with these specifications:

1. OS: Windows 10
2. CUDA Toolkit Version: 11.2 (Download it from here)
3. Python Version: Python 3.6.8 (You can download the executable installer for Windows 10 from here)
4. Unity ML Agents (Udacity Version): A managed build of Unity ML Agents framework, which can be found in the folder unity-ml-agents-setup; you just have to go into the folder and run pip install .. This only needs to be installed for the environment banana-collector.

Here are the exact steps:

1. Clone this repository with (use Git Bash for Windows) git clone https://github.com/RishabhMalviya/dqn-experiments.git.
2. In the cloned repository, create a venv by running the following command from Powershell (venv should be installed along with the Python 3.6.8 installation form the link given above): python -m venv ./venv. Also, in case you're using Anaconda, you should launch Powershell by searching for "Anaconda Powershell Prompt" from Start.
3. We can't pip install the requirements.txt just yet because one of the dependencies, box2d-py, requires a build tool called Swig, which we'll have to install first:
   1. As the Windows documentation for Swig says, Download the swigwin zip package from the SWIG website and unzip into a directory. This is all that needs downloading for the Windows platform. Note that the installation directory needs to be in your PATH environment variable.
   2. To get Swig to build box2d-py correctly, you will also have to set the following two environment variables. Change </path/to/python> to correspond to the python with which you created the venv:
      1. PYTHON_INCLUDE: </path/to/python>/include
      2. PYTHON_LIB: </path/to/python>/libs/python36.lib
4. Now, activate the venv by running ./venv/Scripts/activate in Powershell.
5. Upgrade pip with pip install -U pip.
6. And install the requirements with pip install -r requirements.txt. You should adapt the first three lines of the requirements.txt file based on the installation command that the PyTorch download page recommends for your system.
7. Run cd ./unity-ml-agents-setup and pip install . also if you plan on working with Unity ML Agents or running the notebook in banana-collector.
8. Finally, start a Jupyter Notebook (run jupyter notebook from Powershell) from the root of the repo and hack away!

At a minimum, the following four objects need to be instantiated for running an experiment on any of the environments:

This will be an OpenAI gym enviroment, or a Unity ML Agents environment, if you're running the banana-collector experiment.

Make sure you've gone through the steps in Local Setup, if you want to use the Box 2D OpenAI gym environments.

Depending on which agent you are using, you may have to instantiate additional 'sub-objects'. For example, the DQNAgent requires a DQN (torch nn.Module) and an optional DQNHyperparameters object during initialization.

Further details can be found in the agents' README.md

The hyperparameters used during training are defined in the TrainingHyperparameters class in the train_and_visualize.py file (and train_and_visualize_unity.py file). These are the defaults:

self.EPS_START = 1.0
self.EPS_END = 0.01
self.EPS_DECAY = 0.995

The agent can then be set free to interact with environment and learn using the train_agent function from the train_and_visualize.py file (and train_and_visualize_unity.py file). This function takes an argument called completion_criteria, which is supposed to be a function that takes as an argument a list of the scores from the last 100 episodes (latest first), and returns True or False. For example:

train_agent(   
    env=env,
    agent=agent,
    n_episodes=2000,
    max_t=1500,
    completion_criteria=lambda scores_window: np.mean(scores_window) >= 200.0
)

For examples of this in action, go into the folders that are named with an environment name, for example, lunar-lander and explore the Jupyter Notebooks therein.

You can visualize the trained agent (or a randomly behaving agent) and save GIFs of the interaction with the functions save_trained_agent_gif (or save_random_agent_gif) in train_and_visualize.py. Note that this only works for OpenAI Gym environments.

For the equivalent in Unit ML Agents, you can use the functions run_random_agent and run_trained_agent from the train_and_visualize_unity.py file. This won;t save a GIF of the interaction, but it will run it in the Unity window. You'll have to then manually record the interaction from your screen with a software like ScreenToGIF.

And that's it! If you face any problems, or have any questions. please add an Issue to the repo.