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

Multivariate Bernoulli classification


So far, our investigation of the Naïve Bayes has focused on features that are essentially binary {UP=1, DOWN=0}. The mean value is computed as the ratio of the number of observations for which xi = UP over the total number of observations.

As stated in the first section, the Gaussian distribution is more appropriate for either continuous features or binary features in the case of very large labeled datasets. The example is the perfect candidate for the Bernoulli model.

Model

The Bernoulli model differs from the Naïve Bayes classifier in that it penalizes the features x, which does not have any observation; the Naïve Bayes classifier ignores them [5:10].

Note

The Bernoulli mixture model

M8: For a feature function fk with fk = 1 if the feature is observed, 0 otherwise, and the probability p of the observed feature xk belongs to the class Cj, the posterior probability is computed as follows:

Implementation

The implementation of the Bernoulli model consists of...