Building R 4.0.2 from source via clang/xcode for MKL on macOS

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 at 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 at 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.

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