[Rd] About FlexiBLAS in the R-admin docs

[Martin Maechler]

>>>>> George Ostrouchov 
>>>>>     on Wed, 11 Oct 2023 17:12:47 -0400 writes:

    > I agree that the "R Installation and Administration" guide statement about FlexiBLAS needs an update. Standard R in CentOS Stream 9, which is now downstream from Fedora, gives the following result for Matrix products in sessionInfo():
    >> sessionInfo()
    > R version 4.3.1 (2023-06-16)
    > Platform: x86_64-redhat-linux-gnu (64-bit)
    > Running under: CentOS Stream 9

    > Matrix products: default
    > BLAS/LAPACK: FlexiBLAS OPENBLAS-OPENMP;  LAPACK version 3.9.0
    > …

Note that I also am an *occasional* happy user of FlexiBLAS (the
Fedora package *and* the corresponding CRAN package
'flexiblas'), using regular Fedora Linux,
*and* am happy to give public thanks for both to  Iñaki Úcar
(and whoever has helped with the project).


    > So OpenBLAS compiled with OpenMP is the default. FlexiBLAS (via the flexiblas package) is my favorite way to manage core use in multithreaded BLAS computations. It is also the default in the EasyBuild foss compiler toolchain for HPC clusters: https://docs.easybuild.io/common-toolchains/ 

    > What would be a good way to suggest or construct an update?

    > Best regards,
    > George

Thank you, George, for the offering of an update;  to answer the question

Create a patch to the *source* of that manual which is written
in "texinfo".
It is part of R's sources, the latest version hence is always

   https://svn.r-project.org/R/trunk/doc/manual/R-admin.texi

  (or "almost always current" at one of its github mirrors ..)

Best regards,
Martin

--
Martin Maechler
ETH Zurich  and  R Core team


    >> Date: Wed, 27 Sep 2023 15:14:43 +0200
    >> From: Iñaki Ucar <iucar using fedoraproject.org>
    >> To: "r-devel using r-project.org" <R-devel using r-project.org>
    >> Subject: [Rd] About FlexiBLAS in the R-admin docs
    >> 
    >> Hi,
    >> 
    >> Not sure if this is the right place for this. The "R Installation and
    >> Administration" guide states:
    >> 
    >>> Apparently undocumented: FlexiBLAS on Fedora provides a complete LAPACK, but not the enhanced routines from ATLAS or OpenBLAS.
    >> 
    >> I'm not sure what this means. FlexiBLAS does provide 100% of BLAS and
    >> LAPACK, and if the active backend (say, OpenBLAS) implements an
    >> enhanced LAPACK routine, then the call is redirected to the backend.
    >> If the user switches to another backend and that routine is not
    >> available there, then the original LAPACK routine is dispatched
    >> instead.
    >> 
    >> Best,
    >> -- 
    >> Iñaki Úcar