Book Image

Machine Learning with Spark - Second Edition

By : Rajdeep Dua, Manpreet Singh Ghotra
Book Image

Machine Learning with Spark - Second Edition

By: Rajdeep Dua, Manpreet Singh Ghotra

Overview of this book

This book will teach you about popular machine learning algorithms and their implementation. You will learn how various machine learning concepts are implemented in the context of Spark ML. You will start by installing Spark in a single and multinode cluster. Next you'll see how to execute Scala and Python based programs for Spark ML. Then we will take a few datasets and go deeper into clustering, classification, and regression. Toward the end, we will also cover text processing using Spark ML. Once you have learned the concepts, they can be applied to implement algorithms in either green-field implementations or to migrate existing systems to this new platform. You can migrate from Mahout or Scikit to use Spark ML. By the end of this book, you will acquire the skills to leverage Spark's features to create your own scalable machine learning applications and power a modern data-driven business.
Table of Contents (13 chapters)

Evaluating the impact of text processing

Text processing and tf-idf weighting are examples of feature extraction techniques designed to both reduce the dimensionality of, and extract some structure from, raw text data. We can see the impact of applying these processing techniques by comparing the performance of a model trained on raw text data with one trained on processed and tf-idf weighted text data.

Comparing raw features with processed tf-idf features on the 20 Newsgroups dataset

In this example, we will simply apply the hashing term frequency transformation to the raw text tokens obtained using a simple whitespace splitting of the document text. We will train a model on this data and evaluate the performance on the test set as we did for the model trained with...