Book Image

Apache Spark 2.x Cookbook

By : Rishi Yadav
Book Image

Apache Spark 2.x Cookbook

By: Rishi Yadav

Overview of this book

While Apache Spark 1.x gained a lot of traction and adoption in the early years, Spark 2.x delivers notable improvements in the areas of API, schema awareness, Performance, Structured Streaming, and simplifying building blocks to build better, faster, smarter, and more accessible big data applications. This book uncovers all these features in the form of structured recipes to analyze and mature large and complex sets of data. Starting with installing and configuring Apache Spark with various cluster managers, you will learn to set up development environments. Further on, you will be introduced to working with RDDs, DataFrames and Datasets to operate on schema aware data, and real-time streaming with various sources such as Twitter Stream and Apache Kafka. You will also work through recipes on machine learning, including supervised learning, unsupervised learning & recommendation engines in Spark. Last but not least, the final few chapters delve deeper into the concepts of graph processing using GraphX, securing your implementations, cluster optimization, and troubleshooting.
Table of Contents (19 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Dimensionality reduction with principal component analysis


Dimensionality reduction is the process of reducing the number of dimensions or features. A lot of real data contains a very high number of features. It is not uncommon to have thousands of features. So we need to drill down to features that matter.

Dimensionality reduction serves several purposes, such as:

  • Data compression
  • Visualization

When the number of dimensions is reduced, it reduces the disk and memory footprint. Last but not least, it helps algorithms to run faster. It also helps reduce highly correlated dimensions to one.

Humans can only visualize three dimensions, but data has access to a much higher number of dimensions. Visualization can help find hidden patterns in a particular piece of data. Dimensionality reduction helps visualization by compacting multiple features into one.

The most popular algorithm for dimensionality reduction is principal component analysis (PCA).

Let's look at the following dataset:

Let's say the goal...