[Rd] invoking R function in C++ in parallel

Zheng Da zhengda1936 at gmail.com
Sun Feb 1 03:27:22 CET 2015

Thank you both.
I think I have got the answer I need.
I'll need to turn to another direction to search for my solution.


On Sat, Jan 31, 2015 at 8:32 PM, Dirk Eddelbuettel <edd at debian.org> wrote:
> On 31 January 2015 at 19:29, Gábor Csárdi wrote:
> | On Sat, Jan 31, 2015 at 7:05 PM, Dirk Eddelbuettel <edd at debian.org> wrote:
> | [...]
> |
> |     - either work in something like OpenMP and run in multiple threads that
> |        remain /completely/ shielded from R, ie no R calls, and not even R data
> |        types as you cannot trigger gc() calls from different threads
> |
> |
> | I think you can use R objects, as long as you don't call R functions on them
> | (not even from R's C api, although some of them are currently fine) and
> | consider them as read-only. E.g. if you have a numeric vector, you can do
> | double *cvec = REAL(vec);
> | and then use cvec in your thread(s).
> You and I are saying the same thing here: you call it read-only access; I
> called ot "do not use R types". We recommend the same approach in other
> places: instantiate std::vector<double> from RcppVector, don't use R calls.
> My recommendation is to make it pretty plain: do not call R functions. Use
> other types. There are equivalent read-only constructors for some relevant
> data types.
> Recall that OP, in the parts you chose not to quote, asked to call back to R
> in a multithreaded way. And we both say 'nope' here.
> All this has come up before on rcpp-devel and SO.
> Dirk
> --
> http://dirk.eddelbuettel.com | @eddelbuettel | edd at debian.org

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