[R] Rcpp and mclapply

[sophie_brugieres at mpipsykl.mpg.de]

Dear all,

I have an R script that uses Rcpp, and I have been trying to parallelize
it using mclapply (I tried with the multicore and the parallel library)

Sometimes (not always, interestingly), the CPU use for each core drops,
usually so that the total over all cores reaches 100%, i.e., as fast as if
using just one single core fully. I tried my code directly from within
emacs, and also using a shell command - it happens either way.

I suspect there might be some interaction between Rcpp and the
multicore/parallel libraries. Did any R(cpp) user encounter such symptoms?

Sophie