Code optimization, an Rcpp solution

November 10, 2011

(This article was first published on Romain Francois, Professional R Enthusiast - Tag - R, and kindly contributed to R-bloggers)

Tony Breyal woke up an old code optimization problem in this blog post, so I figured it was time for an Rcpp based solution

This solutions moves down Henrik Bengtsson’s idea (which was at the basis of attempt 10) down to C++. The idea was to call sprintf less than the other solutions to generate the strings “001”, “002”, “003”, …

We can benchmark this version using the rbenchmark package:

> library(rbenchmark)
> n <- 2000
> benchmark(
+     generateIndex10(n), 
+     generateIndex11(n),
+     generateIndex12(n), 
+     generateIndex13(n),
+     generateIndex14(n),
+     columns = 
+        c("test", "replications", "elapsed", "relative"),
+     order = "relative",
+     replications = 20
+ )
                test replications elapsed relative
5 generateIndex14(n)           20  21.015 1.000000
3 generateIndex12(n)           20  22.034 1.048489
4 generateIndex13(n)           20  23.436 1.115203
2 generateIndex11(n)           20  23.829 1.133904
1 generateIndex10(n)           20  30.580 1.455151

To leave a comment for the author, please follow the link and comment on their blog: Romain Francois, Professional R Enthusiast - Tag - R. offers daily e-mail updates about R news and tutorials on topics such as: Data science, Big Data, R jobs, visualization (ggplot2, Boxplots, maps, animation), programming (RStudio, Sweave, LaTeX, SQL, Eclipse, git, hadoop, Web Scraping) statistics (regression, PCA, time series, trading) and more...

If you got this far, why not subscribe for updates from the site? Choose your flavor: e-mail, twitter, RSS, or facebook...

Comments are closed.


Never miss an update!
Subscribe to R-bloggers to receive
e-mails with the latest R posts.
(You will not see this message again.)

Click here to close (This popup will not appear again)