Book Image

Deep Reinforcement Learning Hands-On - Second Edition

By : Maxim Lapan
5 (1)
Book Image

Deep Reinforcement Learning Hands-On - Second Edition

5 (1)
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)
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Index

Noisy networks

The next improvement that we are going to look at addresses another RL problem: exploration of the environment. The paper that we will draw from is called Noisy Networks for Exploration ([4] Fortunato and others, 2017) and it has a very simple idea for learning exploration characteristics during training instead of having a separate schedule related to exploration.

Classical DQN achieves exploration by choosing random actions with a specially defined hyperparameter epsilon, which is slowly decreased over time from 1.0 (fully random actions) to some small ratio of 0.1 or 0.02. This process works well for simple environments with short episodes, without much non-stationarity during the game; but even in such simple cases, it requires tuning to make the training processes efficient.

In the Noisy Networks paper, the authors proposed a quite simple solution that, nevertheless, works well. They add noise to the weights of fully connected layers of the network and adjust...