Book Image

Apache Spark Machine Learning Blueprints

By : Alex Liu
Book Image

Apache Spark Machine Learning Blueprints

By: Alex Liu

Overview of this book

There's a reason why Apache Spark has become one of the most popular tools in Machine Learning – its ability to handle huge datasets at an impressive speed means you can be much more responsive to the data at your disposal. This book shows you Spark at its very best, demonstrating how to connect it with R and unlock maximum value not only from the tool but also from your data. Packed with a range of project "blueprints" that demonstrate some of the most interesting challenges that Spark can help you tackle, you'll find out how to use Spark notebooks and access, clean, and join different datasets before putting your knowledge into practice with some real-world projects, in which you will see how Spark Machine Learning can help you with everything from fraud detection to analyzing customer attrition. You'll also find out how to build a recommendation engine using Spark's parallel computing powers.
Table of Contents (18 chapters)
Apache Spark Machine Learning Blueprints
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Model evaluation


After completing our model estimation as described in the preceding section, we need to evaluate these estimated models to see if they fit our client's criterion so that we can either move to the explanation of results or go back to some previous stage to refine our predictive models.

To perform our model evaluation, in this section, we will utilize confusion matrix numbers to assess the quality of fit for our models, and then expand to other statistics.

As always, to calculate them, we need to use our test data rather than the training data.

Confusion matrix

In R, we can produce the model's performance indices with the following code:

model$confusion

Once a cutting point is determined, the following confusion matrix is produced, which shows a good result:

Model's Performance

Predicted as Default

Predicted as NOT (Good)

Actual Default

89%

11%

Actual Not (Good)

12%

88%

For this project, the preceding table is the most important evaluation, as the company wants to increase...