Gavin, thanks, quick updates inline.
> On Apr 25, 2025, at 9:53 PM, Gavin Simpson <ucfa...@gmail.com> wrote: > > Thanks Simon, that's really helpful - I find the R manuals confusing on this > issue in part because things MacOS X related are bound up in "Unix-alike" > sections and there are often clauses and / or footnotes relating to MacOS X > but it's unclear what relates to CRAN builds / configuration vs doing things > on one's own system. If I were more knowledgeable about this stuff I would > suggest some changes, but perhaps it's clear once one has gained sufficient > knowledge :-) > > I've had another close read of data.table's configure script and I think I > understand what is needed so that I can try to help Simon (Wood) and Ben and > Mollie with getting this configured in mgcv and glmmTMB using the relevant > bits from data.table. > Basically, the main part is to detect OpenMP even if R doesn't enable it (possibly as an option?) and on macOS also try -Xclang in front of the regular -fopemp to see if it works. > And again, thank you for helping me through all this, and - because I'm sure > it doesn't get said enough - for everything you do to support R on Mac! > > FYI: there does seem to be a real problem related to OpenMP with clang 1700 > provided in Xcode 16.3 (which got installed when or alongside the system > updates for Sequoia 15.4.1) - I'm seeing the same issue reported here > https://github.com/Rdatatable/data.table/issues/6622 and down some deep > rabbit hole I went digging into the error message I saw during compilation of > mcgv I saw reports that this was a bug in llvm that was affecting this > version of clang, but I can't find the source for that now. I've downgraded > to 16.2 now so I just have one problem to solve (compile my own R or ditch > homebrew). > Yes, I have confirmed in the meantime that Xcode 16.3 (using LLVM 19) is incompatible with earlier OpenMP run-times, and I have added the corresponding note on the OpenMP pages: https://mac.r-project.org/openmp/ including a work-around if you want to use Xcode 16.3 and force the corresponding LLVM 19 run-time in the complied package instead of the shared one. Note that you still can't mix them in the same R session, so you have to to choose which run-time to use for *all* packages that require OpenMP (at least the ones you want to load together ;)). > The other day I said I had R installed from Homebrew and that it was CRAN's > binary. This is true, but I neglected the difference between installing R as > a formula or as a cask. The latter installs CRAN's binary of R, while > installing as a formula would lead to a local compilation from sources using > Homebrew. Sorry about that confusion. > No worries, it's all complicated :), but that makes sense. Cheers, Simon _______________________________________________ R-SIG-Mac mailing list R-SIG-Mac@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-mac
