Book Image

Python Reinforcement Learning

By : Sudharsan Ravichandiran, Sean Saito, Rajalingappaa Shanmugamani, Yang Wenzhuo
Book Image

Python Reinforcement Learning

By: Sudharsan Ravichandiran, Sean Saito, Rajalingappaa Shanmugamani, Yang Wenzhuo

Overview of this book

Reinforcement Learning (RL) is the trending and most promising branch of artificial intelligence. This Learning Path will help you master not only the basic reinforcement learning algorithms but also the advanced deep reinforcement learning algorithms. The Learning Path starts with an introduction to RL followed by OpenAI Gym, and TensorFlow. You will then explore various RL algorithms, such as Markov Decision Process, Monte Carlo methods, and dynamic programming, including value and policy iteration. You'll also work on various datasets including image, text, and video. This example-rich guide will introduce you to deep RL algorithms, such as Dueling DQN, DRQN, A3C, PPO, and TRPO. You will gain experience in several domains, including gaming, image processing, and physical simulations. You'll explore TensorFlow and OpenAI Gym to implement algorithms that also predict stock prices, generate natural language, and even build other neural networks. You will also learn about imagination-augmented agents, learning from human preference, DQfD, HER, and many of the recent advancements in RL. By the end of the Learning Path, you will have all the knowledge and experience needed to implement RL and deep RL in your projects, and you enter the world of artificial intelligence to solve various real-life problems. This Learning Path includes content from the following Packt products: • Hands-On Reinforcement Learning with Python by Sudharsan Ravichandiran • Python Reinforcement Learning Projects by Sean Saito, Yang Wenzhuo, and Rajalingappaa Shanmugamani
Table of Contents (27 chapters)
Title Page
About Packt
Contributors
Preface
Index

Implementing AlphaGo Zero


At last, we will implement AlphaGo Zero in this section. In addition to achieving better performance than AlphaGo, it is in fact relatively easier to implement. This is because, as discussed, AlphaGo Zero only relies on selfplay data for learning, and thus relieves us from the burden of searching for large amounts of historical data. Moreover, we only need to implement one neural network that serves as both the policy and value function. The following implementation makes some further simplifications—for example, we assume that the Go board size is 9 instead of 19. This is to allow for faster training.

The directory structure of our implementation looks such as the following:

alphago_zero/
|-- __init__.py
|-- config.py
|-- constants.py
|-- controller.py
|-- features.py
|-- go.py
|-- mcts.py
|-- alphagozero_agent.py
|-- network.py
|-- preprocessing.py
|-- train.py
`-- utils.py

We will especially pay attention to network.py and mcts.py, which contain the implementations...