search for: rcpparallel

...ompiled) code with R. All of them stress (and I simplify here) that can you touch R objects, or call back into R, for fear of any assignment or allocation triggering an R event. R being single-threaded it cannot do this. My answer to this problem is to only use non-R data structures. That is what RcpParallel does in the actual parallel code portions in all examples -- types RVector and RMatrix do NOT connect back to R. There are several working examples. That is also what the OpenMP examples at the Rcpp Gallery do. Charles seems to be replying 'but I use XPtr' or 'I use XPtr on arma::mat...

...stress (and I simplify here) that can you touch R objects, or call > back > into R, for fear of any assignment or allocation triggering an R event. R > being single-threaded it cannot do this. > > My answer to this problem is to only use non-R data structures. That is > what > RcpParallel does in the actual parallel code portions in all examples -- > types RVector and RMatrix do NOT connect back to R. There are several > working > examples. That is also what the OpenMP examples at the Rcpp Gallery do. > > Charles seems to be replying 'but I use XPtr' or '...

R Developers, Could someone help explain what it means that R is single threaded? I am trying to understand what is actually going on inside R when users want to parallelize code. For example, using mclapply or foreach (with some backend) somehow allows users to benefit from multiple CPUs. Similarly there is the RcppParallel package for RMatrix/RVector objects. But none of these address the