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

Doing classification using logistic regression


In classification, the response variable y has discreet values as opposed to continuous values. Some examples are e-mail (spam/non-spam), transactions (safe/fraudulent), and so on.

The y variable can take two values, namely 0 or 1, as illustrated in the following equation:

Here, 0 is referred to as a negative class and 1 means a positive class. Though we are calling them positive or negative, it is only for convenience's sake. Algorithms are neutral about this assignment. Algorithms have no emotions, and 1 does not mean higher than or better than 0

Though linear regression works well with regression tasks, it hits a few limitations when it comes to classification tasks. These include:

  • The fitting process is very susceptible to outliers
  • There is no guarantee that the hypothesis function h(x) will fit in the range of 0 (negative class) to 1 (positive class)

Logistic regression guarantees that h(x) will fit between 0 and 1. Though logistic regression...