On point 1): The standard approach seems to favor the reference BLAS for reasons other than speed.
For example, vecLib, Apple's multi-threaded BLAS library, is not the default choice for macOS binaries due to concerns about 'precision'. See: https://cloud.r-project.org/bin/macosx/RMacOSX-FAQ.html#Whic h-BLAS-is-used-and-how-can-it-be-changed_003f This doesn't appear to be Mac- or vecLib-specifc. R-Core seem wary of non-reference BLAS implementations for several reasons: 'External BLAS implementations often make less use of extended-precision floating-point registers and will almost certainly re-order computations. This can result in less accuracy than using the internal BLAS, and may result in different solutions, e.g. different signs in SVD and eigendecompositions.' https://cran.r-project.org/doc/manuals/r-devel/R-admin.html#BLAS I'm not sure how pervasive a problem this is, though. Keith On Sat, Dec 16, 2017 at 4:01 PM, Dirk Eddelbuettel <e...@debian.org> wrote: > > Kenny, > > On 17 December 2017 at 09:28, Kenny Bell wrote: > | Hi R-devel list, > | > | OpenBLAS is readily available for unix-likes: > | > | https://cloud.r-project.org/web/packages/gcbd/vignettes/gcbd.pdf > > Please consider re-reading this vignette of mine. BLAS is an interface, > OpenBLAS is but one implementation. R has allowed you to switch between > different implementations for a long time (if you used a shared library > build), and illustrating / measuring the possible performance differences > is > the whole point of the gcbd benchmarking package. > > | However, my questions are: > | > | 1) Would R-devel consider using OpenBLAS for the main distribution of R > for > | all platforms including Windows? > | 2) If so, would R-devel set the default multi-thread level to the number > of > | (real) cores on a machine? > > It's complicated. If you fork at the process-level (with package parallel > or > one of the many other mechansim) and then also used multi-threaded BLAS you > can starve yourself for resources quickly. > > | My sense is there're a lot of wasted resources on laptops and personal > | desktops around the world that could be utilised by such a switch. I > | believe most unix-like users don't know about OpenBLAS and are blissfully > | ignorant of the available speed gains. It seems to be quite difficult > for a > | typical Windows user to get this done today. > > Many things a developer / power-user would do are very difficult on > Windows. It is one of the charms of the platform. On the other hand you do > get a few solitaire games so I guess everybody is happy. > > Dirk > > | Thanks heaps, > | Kenny > | > | [[alternative HTML version deleted]] > | > | ______________________________________________ > | R-devel@r-project.org mailing list > | https://stat.ethz.ch/mailman/listinfo/r-devel > > -- > http://dirk.eddelbuettel.com | @eddelbuettel | e...@debian.org > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel > [[alternative HTML version deleted]] ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
