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

Play and train in separate processes

At a high level, our training contains a repetition of the following steps:

  1. Ask the current network to choose actions and execute them in our array of environments
  2. Put observations into the replay buffer
  3. Randomly sample the training batch from the replay buffer
  4. Train on this batch

The purpose of the first two steps is to populate the replay buffer with samples from the environment (which are observation, action, reward, and next observation). The last two steps are for training our network.

The following is an illustration of the preceding steps that will make potential parallelism slightly more obvious. On the left, the training flow is shown. The training steps use environments, the replay buffer, and our NN. The solid lines show data and code flow.

Dotted lines represent usage of the NN for training and inference.

Figure 9.6: A sequential diagram of the training process

As you can see, the top two steps...