Book Image

TensorFlow Reinforcement Learning Quick Start Guide

By : Kaushik Balakrishnan
Book Image

TensorFlow Reinforcement Learning Quick Start Guide

By: Kaushik Balakrishnan

Overview of this book

Advances in reinforcement learning algorithms have made it possible to use them for optimal control in several different industrial applications. With this book, you will apply Reinforcement Learning to a range of problems, from computer games to autonomous driving. The book starts by introducing you to essential Reinforcement Learning concepts such as agents, environments, rewards, and advantage functions. You will also master the distinctions between on-policy and off-policy algorithms, as well as model-free and model-based algorithms. You will also learn about several Reinforcement Learning algorithms, such as SARSA, Deep Q-Networks (DQN), Deep Deterministic Policy Gradients (DDPG), Asynchronous Advantage Actor-Critic (A3C), Trust Region Policy Optimization (TRPO), and Proximal Policy Optimization (PPO). The book will also show you how to code these algorithms in TensorFlow and Python and apply them to solve computer games from OpenAI Gym. Finally, you will also learn how to train a car to drive autonomously in the Torcs racing car simulator. By the end of the book, you will be able to design, build, train, and evaluate feed-forward neural networks and convolutional neural networks. You will also have mastered coding state-of-the-art algorithms and also training agents for various control problems.
Table of Contents (11 chapters)

Deep Deterministic Policy Gradient

We will now delve into the DDPG algorithm, which is a state-of-the-art RL algorithm for continuous control. It was originally published by Google DeepMind in 2016 and has gained a lot of interest in the community, with several new variants proposed thereafter. As was the case in DQN, DDPG also uses target networks for stability. It also uses a replay buffer to reuse past data, and therefore, it is an off-policy RL algorithm.

The ddpg.py file is the main file from which we start the training and testing. It will call the training or testing functions, which are present in TrainOrTest.py. The AandC.py file has the TensorFlow code for the actor and the critic networks. Finally, replay_buffer.py stores the samples in a replay buffer by using a deque data structure. We will train the DDPG to learn to hold an inverted pendulum vertically, using OpenAI...