Romain Francois, Professional R Enthusiast

Here comes yet another sequel of the code optimization problem from the R wiki, still using Rcpp, but with a different strategy this time

Essentially, my previous version (15) was using stringstream although we don't really need its functionality and it was slowing us down

Also, the characters "i" and "." are always on the same position so we can assign them once and for all

So without further ado, here is attempt 17:

With quite a speedup from attempt 15:

                test replications elapsed relative
2 generateIndex17(n)           20   9.363 1.000000
1 generateIndex15(n)           20  17.795 1.900566

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
>    

Following last post about partnership with R Bloggers, Tal and I have added a small widget to the gallery main page to present links to recent posts on R Bloggers

It uses the wordpress api to grab information about the rss feed generated by R Bloggers and displays links one at a time using the same jquery magic as we've used in the widget that was integrated in R Bloggers a few days ago

I've added a twitter search widget that searches for the #rgraphgallery hashtag or the url of the gallery on the front page.

I've just created a facebook page about the R Graph Gallery

I hope this will improve the experience of the website by making it more social, for example, I anticipate that people will share their own graphs by sending a picture on the facebook page wall

As part of this, I've added the usual "find us on facebook" widget on the home page of the gallery

I've added facebook like button in the home page of the R Graph Gallery and on each image page, i.e. this one which I "like".

Dirk and I gave a full day Rcpp workshop yesterday in Chicago before the R in Finance conference.

The pdfs of the slides are available here: part 1 (intro), part 2 (details), part 3 (modules) and part 4 (applications)

Overview

This year's R/Finance conference will be preceded by a full-day masterclass on Rcpp and related topics which will be held on Thursday, April 28, 2011, the Univ. of Illinois at Chicago campus.

Join Dirk Eddelbuettel and Romain Francois for six hours of detailed and hands-on instructions and discussions around Rcpp, inline, RInside, RcppArmadillo and other packages---in intimate small-group setting.

The full-day format allows to combine a morning introductory session with a more advanced afternoon session while leaving room for sufficient breaks. There will be about six hours of instructions, a one-hour lunch break and two half-hour coffee breaks.

Morning session: "A hands-on introduction to R and C++"

The morning session will provide a practical introduction to the Rcpp package (and other related packages). The focus will be on simple and straightforward applications of Rcpp in order to extend R and/or to significantly accelerate the execution of simple functions.

The tutorial will cover the inline package which permits embedding of self-contained C, C++ or Fortran code in R scripts. We will also discuss RInside to embed R code in C++ applications, as well as standard Rcpp extension packages such as RcppArmadillo for linear algebra and RcppGSL.

Afternoon session: "Advanced R and C++ topics"

This afternoon tutorial will provide a hands-on introduction to more advanced Rcpp features. It will cover topics such as writing packages that use Rcpp, how 'Rcpp modules' and the new R ReferenceClasses interact, and how 'Rcpp sugar' lets us write C++ code that is often as expressive as R code. Another possible topic, time permitting, may be writing glue code to extend Rcpp to other C++ projects.

We also hope to leave some time to discuss problems brought by the class participants.

Prerequisites

Knowledge of R as well as general programming knowledge; C or C++ knowledge is helpful but not required.

Users should bring a laptop set up so that R packages can be built. That means on Windows, Rtools needs to be present and working, and on OS X the Xcode package should be installed.

Registration

Registration is available via the R/Finance conference at

or directly at RegOnline

The cost is USD 500 for the whole day, and space will be limited.

Questions

Please contact us directly at RomainAndDirk@r-enthusiasts.com

I'll present Rcpp at the inaugural Geneva-R meeting.

Geneva-R is an informal gathering of R enthusiasts sponsored by Mango Solutions, that builds on the success of London-R, where I presented twice, and Basel-R

This is I guess off topic in this blog, but after a few years off, I'm back on stage doing some stand up comedy, as part of the Montpellier Comédie Club

See me on youtube:

Some press coverage and pictures: soonlight

Local news report (France 3 Montpellier)