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

Custom layers

In the previous section, I briefly mentioned the nn.Module class as a base parent for all NN building blocks exposed by PyTorch. It's not just a unifying parent for the existing layers—it's much more than that. By subclassing the nn.Module class, you can create your own building blocks, which can be stacked together, reused later, and integrated into the PyTorch framework flawlessly.

At its core, the nn.Module provides quite rich functionality to its children:

  • It tracks all submodules that the current module includes. For example, your building block can have two feed-forward layers used somehow to perform the block's transformation.
  • It provides functions to deal with all parameters of the registered submodules. You can obtain a full list of the module's parameters (parameters() method), zero its gradients (zero_grads() method), move to CPU or GPU (to(device) method), serialize and deserialize the module (state_dict() and load_state_dict...