[Rcpp-devel] Segfault error during simulation in Rcpp

[Jonathan Olmsted]

Matteo,



> The other obvious of course is that you are not forced to control a loop
> over
> 10^6 elements from R either:  pass N=10^6 down to C++ code, and run your N
> loops there.  You will also get a considerable speed boost.
>
>
^ I could have been more explicit. This is what I meant. You might may or
may not be able to do this in the sourceCpp() framework, though. How you do
this is much more obvious if you go the route of making an Rcpp package.
For as much as the convenience functions are a blessing, I've always found
it hard to think about how I'd do more complex things with them. It could
be possible, I just don't see it. I find the package approach to be a nice
balance between abstracting away from some details but keeping some in the
forefront of your mind. If you email me off the list and I can send you a
very small package that using Rcpp. Multiple C++ functions are created,
only some are exposed to R.

It seems like you'd probably do something similar.

-Jonathan





>  | On Thu, May 16, 2013 at 8:11 PM, Dirk Eddelbuettel <edd at debian.org>
> wrote:
> |
> |
> |     On 16 May 2013 at 14:49, Jonathan Olmsted wrote:
> |     | Several things.
> |     |
> |     | Xiao, Dirk's code gives me a segfault immediately and reliably.
> |     |
> |     | All, when I do this whole song and dance using the "old"
> Rcpp/inline/
> |     | cxxfunction approach, I don't have any issues. One obvious
> difference you
> |     can
> |     | see (like was mentioned) in the generated code (visibile using
> verbose=
> |     TRUE) is
> |     | the declaration of an RNGScope object.
> |     |
> |     | But, if the memory issue crops up when you call a C++
> function (syncing
> |     with
> |     | R's RNG state) 1e6 times AND you are already writing C++ maybe
> this is
> |     an
> |     | opportunity to just put one more layer of the code into C++ and
> create
> |     only one
> |     | such RNGScope object?
> |
> |     Beautiful. So we get to blame R Core after all?  ;-)
> |
> |     Dirk
> |
> |     --
> |     Dirk Eddelbuettel | edd at debian.org | http://dirk.eddelbuettel.com
> |     _______________________________________________
> |     Rcpp-devel mailing list
> |     Rcpp-devel at lists.r-forge.r-project.org
> |
> https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel
> |
> |
>
> --
> Dirk Eddelbuettel | edd at debian.org | http://dirk.eddelbuettel.com
>
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