Book Image

Deep Reinforcement Learning Hands-On - Second Edition

By : Maxim Lapan
5 (2)
Book Image

Deep Reinforcement Learning Hands-On - Second Edition

5 (2)
By: Maxim Lapan

Overview of this book

Deep Reinforcement Learning Hands-On, Second Edition is an updated and expanded version of the bestselling guide to the very latest reinforcement learning (RL) tools and techniques. It provides you with an introduction to the fundamentals of RL, along with the hands-on ability to code intelligent learning agents to perform a range of practical tasks. With six new chapters devoted to a variety of up-to-the-minute developments in RL, including discrete optimization (solving the Rubik's Cube), multi-agent methods, Microsoft's TextWorld environment, advanced exploration techniques, and more, you will come away from this book with a deep understanding of the latest innovations in this emerging field. In addition, you will gain actionable insights into such topic areas as deep Q-networks, policy gradient methods, continuous control problems, and highly scalable, non-gradient methods. You will also discover how to build a real hardware robot trained with RL for less than $100 and solve the Pong environment in just 30 minutes of training using step-by-step code optimization. In short, Deep Reinforcement Learning Hands-On, Second Edition, is your companion to navigating the exciting complexities of RL as it helps you attain experience and knowledge through real-world examples.
Table of Contents (28 chapters)
26
Other Books You May Enjoy
27
Index

The Bellman equation of optimality

To explain the Bellman equation, it's better to go a bit abstract. Don't be afraid; I'll provide concrete examples later to support your learning! Let's start with a deterministic case, when all our actions have a 100% guaranteed outcome. Imagine that our agent observes state s0 and has N available actions. Every action leads to another state, s1 ... sN, with a respective reward, r1 ... rN. Also, assume that we know the values, Vi, of all states connected to state s0. What will be the best course of action that the agent can take in such a state?

Figure 5.3: An abstract environment with N states reachable from the initial state

If we choose the concrete action, ai, and calculate the value given to this action, then the value will be . So, to choose the best possible action, the agent needs to calculate the resulting values for every action and choose the maximum possible outcome. In other words, . If we are using the...