Book Image

Machine Learning with R Cookbook

By : Yu-Wei, Chiu (David Chiu)
Book Image

Machine Learning with R Cookbook

By: Yu-Wei, Chiu (David Chiu)

Overview of this book

<p>The R language is a powerful open source functional programming language. At its core, R is a statistical programming language that provides impressive tools to analyze data and create high-level graphics.</p> <p>This book covers the basics of R by setting up a user-friendly programming environment and performing data ETL in R. Data exploration examples are provided that demonstrate how powerful data visualization and machine learning is in discovering hidden relationships. You will then dive into important machine learning topics, including data classification, regression, clustering, association rule mining, and dimension reduction.</p>
Table of Contents (21 chapters)
Machine Learning with R Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Resources for R and Machine Learning
Dataset – Survival of Passengers on the Titanic
Index

Calculating the error evolution of the ensemble method


The adabag package provides the errorevol function for a user to estimate the ensemble method errors in accordance with the number of iterations. In this recipe, we will demonstrate how to use errorevol to show the evolution of errors of each ensemble classifier.

Getting ready

You need to have completed the previous recipe by storing the fitted bagging model in the variable, churn.bagging. Also, put the fitted boosting classifier in churn.boost.

How to do it...

Perform the following steps to calculate the error evolution of each ensemble learner:

  1. First, use the errorevol function to calculate the error evolution of the boosting classifiers:

    > boosting.evol.train = errorevol(churn.boost, trainset)
    > boosting.evol.test = errorevol(churn.boost, testset)
    > plot(boosting.evol.test$error, type = "l", ylim = c(0, 1),
    +       main = "Boosting error versus number of trees", xlab = "Iterations",
    +       ylab = "Error", col = "red", lwd = 2...