[R-SIG-Mac] Building R 4.0.2 from source via clang/xcode for MKL on macOS

[Kasper Daniel Hansen]

In my understanding, almost all of the speed up comes from using an
optimized BLAS. Optimizing LAPACK tend to have negligible impact on
performance. At least that is my impression, although I won't say I'm an
expert.

Best,
Kasper

On Tue, Sep 29, 2020 at 9:53 AM roy <rollinforall using gmail.com> wrote:

> Hi Simon,
> Thanks for the info.  I was totally unaware of ABI, vecLib, etc and that
> Apple has blas, lapack, etc.  But after reading up on this and re-reading
> your email, I'm beginning to understand more about this.
>
> So, I would like to first checkout vecLib.  From what you say, would I have
> to do something like the following?
>
> ./configure --enable-BLAS-shlib --with-blas="-lBLAS"  ...
>
> Is this also possible with LAPACK?
>
> tx again.
> cheers, roy
>
>
> On Mon, Sep 28, 2020 at 3:01 PM Simon Urbanek <simon.urbanek using r-project.org
> >
> wrote:
>
> > Rollin,
> >
> > it has been several years since I last tested MKL, so take it with a
> grain
> > of salt, but in general you don't necessarily have to build R with MKL in
> > order to use it - you only need to use --enable-BLAS-shlib and link to
> any
> > ABI-compatible BLAS which can be vecLib as well. Then you can change the
> > link from vecLib to MKL in the BLAS stub. Note that we only need the C
> ABI,
> > there are wrappers vecLibg95f.* which re-map the F entry points to C
> entry
> > points as to avoid Fortran ABI issues thus you don't care about the
> > Fortran. However, historically, MKL has not been much more performant
> than
> > vecLib so it's unclear if it is worth the hassle. As with any accelerated
> > BLAS, note that this may have effects on results in R.
> >
> > Cheers,
> > Simon
> >
> >
> >
> > > On 28/09/2020, at 7:07 PM, rollin <rollinforall using gmail.com> wrote:
> > >
> > > I wanted to build R from source on macos (10.15.5) so I could include
> > > Intel's MKL.  So I first looked at building R from source without MKL.
> > >
> > > From the installation doc, I modified config.site to have the
> following:
> > >
> > > CC=clang
> > > OBJC=$CC
> > > FC=/usr/local/bin/gfortran
> > > CXX=clang++
> > >
> > >
> > > I then ran configuration via the command:
> > >
> > > ./configure -C --enable-R-shlib --enable-memory-profiling
> > > --x-includes=/opt/X11/include --x-libraries=/opt/X11/lib
> > >
> >
> PKG_CONFIG_PATH=/opt/X11/lib/pkgconfig:/usr/local/lib/pkgconfig:/usr/lib/pkgconfig
> > >
> > >
> > > And received the following information and error:
> > >
> > > checking if bzip2 version >= 1.0.6... no
> > > checking whether bzip2 support suffices... configure: error: bzip2
> > library
> > > and headers are required
> > >
> > >
> > > By looking at the log, I saw a compiler error due to an implicit
> > function.
> > > I then made the following change in config.site:
> > >
> > > CFLAGS='-Wno-implicit-function-declaration -g -O2''
> > >
> > >
> > > And configure now ran without errors.
> > >
> > > However, when I looked at configuring to use MKL, I discovered that MKL
> > on
> > > macos does not support gnu fortran so, unless I purchase Intel's
> Fortran
> > > compiler, it looks like I'm sol.
> > >
> > > Has anyone built R with MKL on macos (10.15)?  In any event, I wanted
> to
> > at
> > > least note the issue and work around I encountered when building R on
> > > macos with clang/xcode.
> > >
> > >       [[alternative HTML version deleted]]
> > >
> > > _______________________________________________
> > > R-SIG-Mac mailing list
> > > R-SIG-Mac using r-project.org
> > > https://stat.ethz.ch/mailman/listinfo/r-sig-mac
> >
> >
>
>         [[alternative HTML version deleted]]
>
> _______________________________________________
> R-SIG-Mac mailing list
> R-SIG-Mac using r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-mac
>


-- 
Best,
Kasper

	[[alternative HTML version deleted]]