handle --with-blas with CMake (benchmarks)

[slayoo]

As pointed out by @pguio in #147, the --with-blas autoconf option does not seem to have a counterpart in CMake build setup

[citibeth]

What does --with-blas do, and what is the default in the CMake build?

…

On Thu, Oct 3, 2019 at 11:34 AM Sylwester Arabas ***@***.***> wrote: As pointed out by @pguio <https://github.com/pguio> in #147 <#147>, the --with-blas autoconf option does not seem to have a counterpart in CMake build setup — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#149?email_source=notifications&email_token=AAOVY5YMFE34M2P3HI2TUKLQMYGG7A5CNFSM4I5EXFKKYY3PNVWWK3TUL52HS4DFUVEXG43VMWVGG33NNVSW45C7NFSM4HPOB7TQ>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAOVY5YTSI2KOS4TOVNCL3DQMYGG7ANCNFSM4I5EXFKA> .

[pguio]

from m4/ac_lib_blas.m4:

Checking to see if there is a usable BLAS library kicking around...
(If so, Blitz++ will use BLAS library to run benchmarks against
if you build the benchmarks. Blitz++ itself does NOT use BLAS).

[citibeth]

So how does CMake get the BLAS library? If this is only used for benchmark programs, I'm losing interest fast.

…

On Thu, Oct 3, 2019 at 11:38 AM Patrick Guio ***@***.***> wrote: from m4/ac_lib_blas.m4: Checking to see if there is a usable BLAS library kicking around... (If so, Blitz++ will use BLAS library to run benchmarks against if you build the benchmarks. Blitz++ itself does NOT use BLAS). — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#149?email_source=notifications&email_token=AAOVY5ZOGGITJFSU6VRKLU3QMYGYFA5CNFSM4I5EXFKKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEAITXRY#issuecomment-538000327>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAOVY54CYU7BDV5U75IKFFLQMYGYFANCNFSM4I5EXFKA> .

[papadop]

The problem with blas is that there are many variations which all requires some code adaptation (cblas, mkl, openblas, acml, veclib, atlas, ....). We have been struggling in the past in trying to offer a comprehensive cmake support of blas in another project. I think we dropped that because it was so difficult, but I will have a look on the current state of that software and try to see if it can be leveraged in blitz.

[papadop]

But I'm quite busy at the moment, so this might take some time....