If it’s not compiled in, why is |libomp.dylib| distributed in R for Mac? Bill
On 4/24/25 17:35, Simon Urbanek wrote: > Gavin, > > >> On Apr 24, 2025, at 9:58 PM, Gavin Simpson<ucfa...@gmail.com> wrote: >> >> Dear list, >> >> I'm trying to clarify my understanding of what is and is not implemented / >> expected in terms of openMP support in R and CRAN package *binaries* for >> MacOS on apple silicon. >> >> I have the CRAN's R binary for MacOS X (apple silicon) and also the CRAN >> binaries for two packages, glmmTMB and mgcv, both of which seem to be >> instrumented (following WRE) to use OpenMP if available. And from >> discussions here I understand that thanks to Simon and others, OpenMP >> support for MacOS X is in R and so should I expect OpenMP to work in these >> two packages? >> > No, OpenMP is not supported by Apple compilers, so R does not enable OpenMP > support. You can see that in the logs, e.g: > > https://mac.r-project.org/logs/log-R-4.5-branch.big-sur.arm64.html > [...] > checking for clang -arch arm64 -std=gnu2x option to support OpenMP... > unsupported > > That said, packages are free to run their own tests if they desire, so > anything further is package-dependent. Most packages simply use R's settings > and thus don't use OpenMP on macOS. > > In cases where the package authors decided that OpenMP is critical for the > package they can choose to add a check for '-Xclang -fopenmp' which will > force Apple compilers to generate OpenMP code *if* a run-time is available > (which is not the case for Apple tools) even if it is not supported by Apple. > In that case the package's CRAN binary will have OpenMP support, because the > run time is available on the CRAN build machines to support such packages. > However, that only applies to the CRAN binaries, it is not supported for > source installation due to the lack of support by Apple. > > Cheers, > Simon > > >> If I am, neither of them is working on various of my Mac systems; model >> fitting is single threaded and the test functions that glmmTMB and mgcv use >> to detect OMP support both return FALSE: >> >> R version 4.5.0 (2025-04-11) -- "How About a Twenty-Six" >> Platform: aarch64-apple-darwin20 (64-bit) >> rMDHR-4e07c29ad14bbec3188329bad0dc7b261e96d29b46dcecbe592890e60a53f114gt; >> glmmTMB::omp_check() >> [1] FALSE >> rMDHR-4e07c29ad14bbec3188329bad0dc7b261e96d29b46dcecbe592890e60a53f114gt; >> mgcv:::mgcv.omp() >> [1] FALSE >> >> Is this reproducible on other's systems? (Could someone run those two bits >> of code on their systems if they use the MacOS X R binary from CRAN and the >> CRAN Mac binaries for the packages - running mgcv's test should be easier as >> this pkg is shipped with the R binary). >> >> I am happy to provide further system details, but at this point I'm mostly >> hoping to clarify what I should expect and whether what I'm seeing is >> typical? >> >> Thanks in advance >> >> Gavin >> >> -- >> Gavin Simpson, PhD [he/him/his] >> [tw] @ucfagls [OrciD] 0000-0002-9084-8413 >> [web] fromthebottomoftheheap.net >> • Assistant Professor >> • Department of Animal & Veterinary Sciences, Aarhus University >> • Adjunct Professor, Department of Biology, University of Regina. >> >> _______________________________________________ >> R-SIG-Mac mailing list >> R-SIG-Mac@r-project.org >> https://stat.ethz.ch/mailman/listinfo/r-sig-mac >> > _______________________________________________ > R-SIG-Mac mailing list > R-SIG-Mac@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-mac ​ [[alternative HTML version deleted]] _______________________________________________ R-SIG-Mac mailing list R-SIG-Mac@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-mac
