[Rcpp-devel] RcppArmadillo

[Dirk Eddelbuettel]

Hi Chuck,

On 15 June 2010 at 12:24, Chuck Anderson wrote:
| I translated some R code I have for training neural networks into C++ 
| using Armadillo and call it using RcppArmadillo.   It was great fun to 
| see how Armadillo allows a pretty direct translation from R to C++.  

Cool. That's pretty much where it is supposed to help.

| However, I only see a speed up of 2 over the R execution time.  I 
| expected much more. 
| 
| What speed up do others see?  Any suggestions for finding execution 
| bottlenecks in my Armadillo code? 

Hard to say from the limited amount of detail you provided. Try profiling.
Google Perftools, Valgrind, ... are useful.

My 'Intro to HPC with R' slides have a section on this and a few related
tools, see http://dirk.eddelbuettel.com/presentations/

-- 
  Regards, Dirk