Book Image

Mastering Machine Learning with R, Second Edition - Second Edition

Book Image

Mastering Machine Learning with R, Second Edition - Second Edition

Overview of this book

This book will teach you advanced techniques in machine learning with the latest code in R 3.3.2. You will delve into statistical learning theory and supervised learning; design efficient algorithms; learn about creating Recommendation Engines; use multi-class classification and deep learning; and more. You will explore, in depth, topics such as data mining, classification, clustering, regression, predictive modeling, anomaly detection, boosted trees with XGBOOST, and more. More than just knowing the outcome, you’ll understand how these concepts work and what they do. With a slow learning curve on topics such as neural networks, you will explore deep learning, and more. By the end of this book, you will be able to perform machine learning with R in the cloud using AWS in various scenarios with different datasets.
Table of Contents (23 chapters)
Title Page
Credits
About the Author
About the Reviewers
Packt Upsell
Customer Feedback
Preface
16
Sources

Multiclass classification


There are a number of approaches to learning in multiclass problems. Techniques such as random forest and discriminant analysis will deal with multiclass while some techniques and/or packages will not, for example, generalized linear models, glm(), in base R. As of this writing, the caretEnsemble package, unfortunately, will not work with multiclasses. However, the Machine Learning in R (mlr) package does support multiple classes and also ensemble methods. If you are familiar with sci-kit Learn for Python, one could say that mlr endeavors to provide the same functionality for R. The mlr and the caret-based packages are quickly turning into my favorites for almost any business problem. I intend to demonstrate how powerful the package is on a multiclass problem, then conclude by showing how to do an ensemble on the Pima data.

For the multiclass problem, we will look at how to tune a random forest and then examine how to take a GLM and turn it into a multiclass learner...