Book Image

Python Deep Learning

By : Valentino Zocca, Gianmario Spacagna, Daniel Slater, Peter Roelants
Book Image

Python Deep Learning

By: Valentino Zocca, Gianmario Spacagna, Daniel Slater, Peter Roelants

Overview of this book

With an increasing interest in AI around the world, deep learning has attracted a great deal of public attention. Every day, deep learning algorithms are used broadly across different industries. The book will give you all the practical information available on the subject, including the best practices, using real-world use cases. You will learn to recognize and extract information to increase predictive accuracy and optimize results. Starting with a quick recap of important machine learning concepts, the book will delve straight into deep learning principles using Sci-kit learn. Moving ahead, you will learn to use the latest open source libraries such as Theano, Keras, Google's TensorFlow, and H20. Use this guide to uncover the difficulties of pattern recognition, scaling data with greater accuracy and discussing deep learning algorithms and techniques. Whether you want to dive deeper into Deep Learning, or want to investigate how to get more out of this powerful technology, you’ll find everything inside.
Table of Contents (18 chapters)
Python Deep Learning
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
Index

Autoencoders


Autoencoders are symmetric networks used for unsupervised learning, where output units are connected back to input units:

Autoencoder simple representation from H2O training book (https://github.com/h2oai/h2o-training-book/blob/master/hands-on_training/images/autoencoder.png)

The output layer has the same size of the input layer because its purpose is to reconstruct its own inputs rather than predicting a dependent target value.

The goal of those networks is to act as a compression filter via an encoding layer, Φ that fits the input vector X into a smaller latent representation (the code) c, and then a decoding layer, Φ tries to reconstruct it back to X':

The loss function is the reconstruction error, which will force the network to find the most efficient compact representation of the training data with minimum information loss. For numerical input, the loss function can be the mean squared error:

If the input data is not numerical but is represented as a vector of bits or multinomial...