Search icon
Arrow left icon
All Products
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Newsletters
Free Learning
Arrow right icon
Learning R Programming

You're reading from  Learning R Programming

Product type Book
Published in Oct 2016
Publisher Packt
ISBN-13 9781785889776
Pages 582 pages
Edition 1st Edition
Languages
Author (1):
Kun Ren Kun Ren
Profile icon Kun Ren

Table of Contents (21) Chapters

Learning R Programming
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
1. Quick Start 2. Basic Objects 3. Managing Your Workspace 4. Basic Expressions 5. Working with Basic Objects 6. Working with Strings 7. Working with Data 8. Inside R 9. Metaprogramming 10. Object-Oriented Programming 11. Working with Databases 12. Data Manipulation 13. High-Performance Computing 14. Web Scraping 15. Boosting Productivity

Boosting code performance


In the previous section, we demonstrated how to use profiling tools to identify a performance bottleneck in the code. In this section, you will learn about a number of approaches to boosting code performance.

Using built-in functions

Previously, we demonstrated the performance difference between my_cumsum1(), my_cumsum2() and the built-in function cumsum(). Although my_cumsum2() is faster than my_cumsum1(), when the input vector contains many numbers, cumsum() is much faster than them. Also, its performance does not decay significantly even as the input gets longer. If we evaluate cumsum, we can see that it is a primitive function:

cumsum 
## function (x)  .Primitive("cumsum") 

A primitive function in R is implemented in C/C++/Fortran, compiled to native instructions, and thus, is extremely efficient. Another example is diff(). Here, we will implement computing vector difference sequence in R:

diff_for <- function(x) { 
  n <- length(x) - 1 
...
lock icon The rest of the chapter is locked
Register for a free Packt account to unlock a world of extra content!
A free Packt account unlocks extra newsletters, articles, discounted offers, and much more. Start advancing your knowledge today.
Unlock this book and the full library FREE for 7 days
Get unlimited access to 7000+ expert-authored eBooks and videos courses covering every tech area you can think of
Renews at ₹800/month. Cancel anytime}