Book Image

Deep Learning with R for Beginners

By : Mark Hodnett, Joshua F. Wiley, Yuxi (Hayden) Liu, Pablo Maldonado
Book Image

Deep Learning with R for Beginners

By: Mark Hodnett, Joshua F. Wiley, Yuxi (Hayden) Liu, Pablo Maldonado

Overview of this book

Deep learning has a range of practical applications in several domains, while R is the preferred language for designing and deploying deep learning models. This Learning Path introduces you to the basics of deep learning and even teaches you to build a neural network model from scratch. As you make your way through the chapters, you’ll explore deep learning libraries and understand how to create deep learning models for a variety of challenges, right from anomaly detection to recommendation systems. The Learning Path will then help you cover advanced topics, such as generative adversarial networks (GANs), transfer learning, and large-scale deep learning in the cloud, in addition to model optimization, overfitting, and data augmentation. Through real-world projects, you’ll also get up to speed with training convolutional neural networks (CNNs), recurrent neural networks (RNNs), and long short-term memory networks (LSTMs) in R. By the end of this Learning Path, you’ll be well-versed with deep learning and have the skills you need to implement a number of deep learning concepts in your research work or projects.
Table of Contents (23 chapters)
Title Page
Copyright and Credits
About Packt
Contributors
Preface
Index

Variational Autoencoders


Variational Autoencoders (VAE) are a more recent take on the autoencoding problem. Unlike autoencoders, which learn a compressed representation of the data, Variational Autoencoders learn the random process that generates such data, instead of learning an essentially arbitrary function as we previously did with our neural networks.

VAEs have also an encoder and decoder part. The encoder learns the mean and standard deviation of a normal distribution that is assumed to have generated the data. The mean and standard deviation are called latent variables because they are not observed explicitly, rather inferred from the data. 

The decoder part of VAEs maps back these latent space points into the data. As before, we need a loss function to measure the difference between the original inputs and their reconstruction. Sometimes an extra term is added, called the Kullback-Leibler divergence, or simply KL divergence. The KL divergence computes, roughly, how much a probability...