Hi, I am wondering why it is the case that in R 3.3.3, calling chngpt:chngptm uses only 1 core, but in later releases, e.g. R 3.4.3, it uses multiple cores on linux. The function chngpt:chngptm has a .Call to invoke a C/C++ function that performs bootstrapping. No explicit parallel computing instructions are used. Thanks, Youyi [[alternative HTML version deleted]]
Jeff Newmiller
2019-Apr-20 16:06 UTC
[R] .Call using multiple cores on linux after R 3.3.3
My guess would be that you are running with a non-CRAN distribution of R like Anaconda or MRAN that has MKL enabled? On April 19, 2019 10:25:57 AM PDT, Youyi Fong <youyifong at gmail.com> wrote:>Hi, I am wondering why it is the case that in R 3.3.3, calling >chngpt:chngptm uses only 1 core, but in later releases, e.g. R 3.4.3, >it >uses multiple cores on linux. The function chngpt:chngptm has a .Call >to >invoke a C/C++ function that performs bootstrapping. No explicit >parallel >computing instructions are used. >Thanks, >Youyi > > [[alternative HTML version deleted]] > >______________________________________________ >R-help at 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.-- Sent from my phone. Please excuse my brevity.
Thanks, Jeff! You are absolutely correct. We have OPENBLAS installed in our environment that causes this. One way to "fix" it is: library(RhpcBLASctl) blas_get_num_procs() blas_set_num_threads(1) stopifnot(blas_get_num_procs()==1) On Sat, Apr 20, 2019 at 9:06 AM Jeff Newmiller <jdnewmil at dcn.davis.ca.us> wrote:> My guess would be that you are running with a non-CRAN distribution of R > like Anaconda or MRAN that has MKL enabled? > > On April 19, 2019 10:25:57 AM PDT, Youyi Fong <youyifong at gmail.com> wrote: > >Hi, I am wondering why it is the case that in R 3.3.3, calling > >chngpt:chngptm uses only 1 core, but in later releases, e.g. R 3.4.3, > >it > >uses multiple cores on linux. The function chngpt:chngptm has a .Call > >to > >invoke a C/C++ function that performs bootstrapping. No explicit > >parallel > >computing instructions are used. > >Thanks, > >Youyi > > > > [[alternative HTML version deleted]] > > > >______________________________________________ > >R-help at 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. > > -- > Sent from my phone. Please excuse my brevity. >[[alternative HTML version deleted]]