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

Finding connected components


A connected component is a subgraph (a graph whose vertices are a subset of the vertex set of the original graph and whose edges are a subset of the edge set of the original graph) in which any two vertices are connected to each other by an edge or a series of edges.

An easy way to understand it would be by taking a look at the road network graph of Hawaii. This state has numerous islands, which are not connected by roads. Within each island, most roads will be connected to each other. The goal of finding the connected components is to find these clusters.

The connected components algorithm labels each connected component of the graph with the ID of its lowest-numbered vertex.

Getting ready

We will build a small graph here for the clusters we know and use connected components to segregate them. Let's look at the following data:

Follower

Followee

John

Pat

Pat

Dave

Gary

Chris

Chris

Bill

The preceding data is a simple one, with six vertices and two clusters. Let's put this data...