Book Image

Reinforcement Learning Algorithms with Python

By : Andrea Lonza
Book Image

Reinforcement Learning Algorithms with Python

By: Andrea Lonza

Overview of this book

Reinforcement Learning (RL) is a popular and promising branch of AI that involves making smarter models and agents that can automatically determine ideal behavior based on changing requirements. This book will help you master RL algorithms and understand their implementation as you build self-learning agents. Starting with an introduction to the tools, libraries, and setup needed to work in the RL environment, this book covers the building blocks of RL and delves into value-based methods, such as the application of Q-learning and SARSA algorithms. You'll learn how to use a combination of Q-learning and neural networks to solve complex problems. Furthermore, you'll study the policy gradient methods, TRPO, and PPO, to improve performance and stability, before moving on to the DDPG and TD3 deterministic algorithms. This book also covers how imitation learning techniques work and how Dagger can teach an agent to drive. You'll discover evolutionary strategies and black-box optimization techniques, and see how they can improve RL algorithms. Finally, you'll get to grips with exploration approaches, such as UCB and UCB1, and develop a meta-algorithm called ESBAS. By the end of the book, you'll have worked with key RL algorithms to overcome challenges in real-world applications, and be part of the RL research community.
Table of Contents (19 chapters)
Free Chapter
1
Section 1: Algorithms and Environments
5
Section 2: Model-Free RL Algorithms
11
Section 3: Beyond Model-Free Algorithms and Improvements
17
Assessments

Summary

In this chapter, we approached two different ways in which to solve an RL problem. The first is through the estimation of state-action values that are used to choose the best next action, so-called Q-learning algorithms. The second involves the maximization of the expected reward policy through its gradient. In fact, these methods are called policy gradient methods. In this chapter, we showed the advantages and disadvantages of such approaches, and demonstrated that many of these are complementary. For example, Q-learning algorithms are sample efficient but cannot deal with continuous action. Instead, policy gradient algorithms require more data, but are able to control agents with continuous actions. We then introduced DPG methods that combine Q-learning and policy gradient techniques. In particular, these methods overcome the global maximization of the Q-learning algorithms...