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)

How pipelines work

We run a sequence of algorithms to process and learn from a given dataset. For example, in text classification, we split each document into words and convert the words into a numerical feature vector. Finally, we learn a predictive model using this feature vector and labels.

Spark ML represents such a workflow as a pipeline, which consists of a sequence of PipelineStages (transformers and estimators) to be run in a particular order.

Each stage in PipelineStages is one of the components, either a transformer or an estimator. The stages are run in a particular order while the input DataFrame flows through the stages.

In the following figure, the dpText document pipeline demonstrates the document workflow where Tokenizer, Hashing, and Logistic Regression are the components of the pipeline. The Pipeline...