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)

Chapter 4

  1. DQN is known to overestimate the state-action value function, Q(s,a). To overcome this, DDQN was introduced. DDQN has fewer problems than DQN regarding the overestimation of Q(s,a).
  2. Dueling network architecture has separate streams for the advantage function and the state-value function. These are then combined to obtain Q(s,a). This branching out and then combining is observed to result in a more stable training of the RL agent.
  1. Prioritized Experience Replay (PER) gives more importance to experience samples where the agent performs poorly, and so these samples are sampled more frequently than other samples where the agent performed well. By frequently using samples where the agent performed poorly, the agent is able to work on its weakness more often, and so PER speeds up the training.
  2. In some computer games, such as Atari Breakout, the simulator has too many frames...