Book Image

Scala for Machine Learning, Second Edition - Second Edition

Book Image

Scala for Machine Learning, Second Edition - Second Edition

Overview of this book

The discovery of information through data clustering and classification is becoming a key differentiator for competitive organizations. Machine learning applications are everywhere, from self-driving cars, engineering design, logistics, manufacturing, and trading strategies, to detection of genetic anomalies. The book is your one stop guide that introduces you to the functional capabilities of the Scala programming language that are critical to the creation of machine learning algorithms such as dependency injection and implicits. You start by learning data preprocessing and filtering techniques. Following this, you'll move on to unsupervised learning techniques such as clustering and dimension reduction, followed by probabilistic graphical models such as Naïve Bayes, hidden Markov models and Monte Carlo inference. Further, it covers the discriminative algorithms such as linear, logistic regression with regularization, kernelization, support vector machines, neural networks, and deep learning. You’ll move on to evolutionary computing, multibandit algorithms, and reinforcement learning. Finally, the book includes a comprehensive overview of parallel computing in Scala and Akka followed by a description of Apache Spark and its ML library. With updated codes based on the latest version of Scala and comprehensive examples, this book will ensure that you have more than just a solid fundamental knowledge in machine learning with Scala.
Table of Contents (27 chapters)
Scala for Machine Learning Second Edition
Credits
About the Author
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface
Index

Sparse autoencoder


Autoencoders are fundamentally unsupervised learning models. They are widely used for feature extraction and dimension reduction. The simplest autoencoders are directly derived from the feed-forward neural network (see the Feed-forward neural network section of Chapter 10, Multilayer Perceptron).

The autoencoder attempts to reconstruct its input and therefore, the output and input layer have the same number of nodes or neurons. A conventional neural network such as the multilayer perceptron predicts a target or output vector y from an input vector x. An autoencoder predicts the output layer as the input layer x which constrains the network topology to be symmetric.

Undercomplete autoencoder

One useful application of autoencoders is the extraction of the features that are relevant to the training set (dimension reduction). The hidden layers are stacked using a symmetric pattern along a central hidden layer as described in the following diagram:

Architecture overview of an autoencoder...