Programming PyTorch for Deep Learning

Preface

Deep Learning in the World Today

Hello and welcome! This book will introduce you to deep learning via PyTorch, an open source library released by Facebook in 2017. Unless you’ve had your head stuck in the ground in a very good impression of an ostrich the past few years, you can’t have helped but notice that neural networks are everywhere these days. They’ve gone from being the really cool bit of computer science that people learn about and then do nothing with to being carried around with us in our phones every day to improve our pictures or listen to our voice commands. Our email software reads our email and produces context-sensitive replies, our speakers listen out for us, cars drive by themselves, and the computer has finally bested humans at Go. We’re also seeing the technology being used for more nefarious ends in authoritarian countries, where neural network–backed sentinels can pick faces out of crowds and make a decision on whether they should be apprehended.

And yet, despite the feeling that this has all happened so fast, the concepts of neural networks and deep learning go back a long way. The proof that such a network could function as a way of replacing any mathematical function in an approximate way, which underpins the idea that neural networks can be trained for many different tasks, dates back to 1989,¹ and convolutional neural networks were being used to recognize digits on check in the late ’90s. There’s been a solid foundation building up all this ...