[Rcpp-devel] Trouble passing arguments to R functions that have been passed in (maybe)

[Dirk Eddelbuettel]

On 10 September 2012 at 22:42, Anthony Lee wrote:
| On 10/09/12 22:05, Dirk Eddelbuettel wrote:
| >
| > I didn't have a lot of time for your post but I suspect your design is broken
| > if you plan to call an R function in each itereation of a C++ loop.
| >
| > Just because you can does not mean you should.
| >
| > Dirk
| >
| 
| In fact, there are some good reasons for doing so, amongst them being 
| the ability to play around with exactly those functions while leaving 
| the rest of the code untouched. Naturally, calling C++ functions 
| directly would be faster, and I was planning on trying to allow for 
| Rcpp::XPtr's to be passed in for special cases, but speed is not the 
| overriding design principle here, not least because I have other 
| projects that focus exclusively on speed. It is also the case that a 
| significant amount of compute will be done in those functions in general 
| (whether they are implemented in C++ or not), so the overhead is not an 
| issue.
| 
| In any case, if I have made a mistake and it is possible to ensure the 
| safety of the R function call, then I would be glad to hear how I can 
| correct it.

One thing I would do differently is avoid use of '_' as a range / column
selector.  

If you must do what you are doing, try doing it on straight vectors which
should reduce the need for temoraries.

Good luck,  Dirk

-- 
Dirk Eddelbuettel | edd at debian.org | http://dirk.eddelbuettel.com