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
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27
Index

Optimality and God's number

What makes the combinatorial optimization problem tricky is that we're not looking for any solution; we're in fact interested in the optimal solution of the problem. The difference is obvious: right after the Rubik's Cube was invented, it was known how to reach the goal state (but it took Ernő Rubik about a month to figure out the first method of solving his own invention, which I guess was a frustrating experience). Nowadays, there are lots of different ways or schemes of cube solving: the beginner's method, the method by Jessica Fridrich (very popular among speedcubers), and so on.

All of them vary by the amount of moves to be taken. For example, a very simple beginner's method requires about 100 rotations to solve the cube using 5…7 sequences of rotations to be memorized. In contrast, the current world record in the speedcubing competition is solving the cube in 4.22 seconds, which requires much fewer steps...