NOFORTRAN compilation

[SanPen]

Hi,

Yesterday I decided to compile and link a NOFORTRAN=1 version of openblas.

Perhaps surprisingly (at least for me) it made my application run noticeably faster on ubuntu compared with linking the version from the repos, aside of the nice fact that I don't have gfortran as a dependency anymore and I could build a MSVC version just with MSVC with zero issues.

What's the down side of NOFORTRAN=1, if any?

Thanks,
Santiago

[martin-frbg]

The primary downside is that you'll have a significantly older version of LAPACK included (the current one is not as "easily" machine-translatable to some semblance of C) - though if you're not interested in LAPACK, you could simply build with NO_LAPACK=1 for a much smaller library. I'd think there has to be something wrong with the repo binary to make it much slower than your own build (perhaps it is significantly older than what you built from source, lacking dedicated support for your cpu ?)
Building with MSVC has the downside that you'll only get plain-C versions of all BLAS functions, as none of the optimized assembly kernels are compilable with MSVC. So performance should be poorer than what you'd get from any other C compiler.

[SanPen]

Thank you Martin!

I'll try to do some more testing on this to see if I get some differences that I can explain.