[Rcpp-devel] rcpp overhead

[Dirk Eddelbuettel]

On 11 March 2012 at 01:33, Kaveh Vakili wrote:
| 
| >Don't take this the wrong way, but we are not here to debug or rewrite your
| >code for you. 
| 
| 
| Thanks Dirk, but i'm not asking for this either.
| 
| The code works....only it doesn't time the same. 
| My question is: is it normal -- is there an 
| overhead in using rcpp and how large is it, 
| typically? 
| 
| I'm was not even so enclined to post my code 
| --my question is more general. 

In that case you get a firm "maybe" in reply.  

You need to understand that there is still nothing for us to go on.  Define
overhead. Relative to what? Do you expect calls of compiled functions to be
faster or slower than interpreted? What about recursion?

Do your homework, and come back with a well-formed question with measurable
objectives. Everything else is just chitchat suitable for a campfire.

And again, if you care to _read_ the archives you will find different people
posting different result with speed increases ranging anywhere from a 'few
times faster' to 'ten (and more) times faster' up to to an increase of
several hundred times on a arguably degenerate problem (of a fibonacci
recursion).

But people also do silly things (eg calling R back each time) and expect it
to be faster.  No mas -- this ain't magic pixie dust. If you use it the wrong
way, you get out what you put in.

Dirk

-- 
"Outside of a dog, a book is a man's best friend. Inside of a dog, it is too
dark to read." -- Groucho Marx