----- Original Message ----- > From: "Milan Bouchet-Valat" <nalimi...@club.fr> > To: "Chris Evans" <chrish...@psyctc.org>, r-help@r-project.org > Sent: Saturday, 17 October, 2015 18:13:40 > Subject: Re: [R] No speed up using the parallel package and ncpus > 1 with > boot() on linux machines
> Le samedi 17 octobre 2015 à 17:18 +0100, Chris Evans a écrit : >> I think I am failing to understand how boot() uses the parallel >> package on linux machines, using R 3.2.2 on three different machines >> with 2, 4 and 8 cores all results in a slow down if I use "multicore" >> and "ncpus". Here's the code that creates a very simple reproducible >> example: ... rest of my post deleted to save space ... > Parallel execution is useful only when the operation you want to run > takes enough time. Here, starting the workers takes more time than > computing the means. You should try with a larger number of replicates, > or a slower computation. > Aha. Makes perfect sense of course and explains what I'm seeing both for this and the real work which also involves bootstrapping a pretty simple function. Merci Milan, Chris ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
