Book Image

Apache Spark 2.x Machine Learning Cookbook

By : Mohammed Guller, Siamak Amirghodsi, Shuen Mei, Meenakshi Rajendran, Broderick Hall
Book Image

Apache Spark 2.x Machine Learning Cookbook

By: Mohammed Guller, Siamak Amirghodsi, Shuen Mei, Meenakshi Rajendran, Broderick Hall

Overview of this book

Machine learning aims to extract knowledge from data, relying on fundamental concepts in computer science, statistics, probability, and optimization. Learning about algorithms enables a wide range of applications, from everyday tasks such as product recommendations and spam filtering to cutting edge applications such as self-driving cars and personalized medicine. You will gain hands-on experience of applying these principles using Apache Spark, a resilient cluster computing system well suited for large-scale machine learning tasks. This book begins with a quick overview of setting up the necessary IDEs to facilitate the execution of code examples that will be covered in various chapters. It also highlights some key issues developers face while working with machine learning algorithms on the Spark platform. We progress by uncovering the various Spark APIs and the implementation of ML algorithms with developing classification systems, recommendation engines, text analytics, clustering, and learning systems. Toward the final chapters, we’ll focus on building high-end applications and explain various unsupervised methodologies and challenges to tackle when implementing with big data ML systems.
Table of Contents (20 chapters)
Title Page
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Coding a quadratic cost function optimization using Gradient Descent (GD) from scratch


In this recipe, we will code an iterative optimization technique called gradient descent (GD) to find the minimum of a quadratic function f(x) = 2x2 - 8x +9.

The focus here shifts from using math to solve for the minima (setting the first derivative to zero) to an iterative numerical method called Gradient Descent (GD) which with a guess and then gets closer to the solution in each iteration using a cost/error function as the guideline.

How to do it...

  1. Start a new project in IntelliJ or in an IDE of your choice. Make sure the necessary JAR files are included.
  1. Set up the path using the package directive: package spark.ml.cookbook.chapter9.
  1. Import the necessary packages.

The scala.util.control.Breaks will allow us to break out of the program. We use this during the debugging phase only when the program fails to converge or gets stuck in a never ending process (for example, when the step size is too large).

import...