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

NN building blocks

In the torch.nn package, you will find tons of predefined classes providing you with the basic functionality blocks. All of them are designed with practice in mind (for example, they support mini-batches, they have sane default values, and the weights are properly initialized). All modules follow the convention of callable, which means that the instance of any class can act as a function when applied to its arguments. For example, the Linear class implements a feed-forward layer with optional bias:

>>> import torch.nn as nn
>>> l = nn.Linear(2, 5)
>>> v = torch.FloatTensor([1, 2])
>>> l(v)
tensor([ 1.0532,  0.6573, -0.3134,  1.1104, -0.4065], grad_fn=<AddBackward0>)

Here, we created a randomly initialized feed-forward layer, with two inputs and five outputs, and applied it to our float tensor. All classes in the torch.nn packages inherit from the nn.Module base class, which you can use to implement...