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

Learning Stochastic and PG Optimization

So far, we've addressed and developed value-based reinforcement learning algorithms. These algorithms learn a value function in order to be able to find a good policy. Despite the fact that they exhibit good performances, their application is constrained by some limits that are embedded in their inner workings. In this chapter, we'll introduce a new class of algorithms called policy gradient methods, which are used to overcome the constraints of value-based methods by approaching the RL problem from a different perspective.

Policy gradient methods select an action based on a learned parametrized policy, instead of relying on a value function. In this chapter, we will also elaborate on the theory and intuition behind these methods, and with this background, develop the most basic version of a policy gradient algorithm, named REINFORCE...