LAPACKE and CBLAS

[mohawk2]

Recent (and indeed for a while) LAPACKs have LAPACKE (the official C interface) and CBLAS (ditto) code routinely distributed. I see Strawberry PDL edition has BLAS and LAPACK DLLs, but it doesn't have the LAPACKE/CBLAS DLLs, nor the headers.

Are you open to adding such?

[shawnlaffan]

We can look at adding them.

Can they enabled as part of the standard build or are they a separate build?

[mohawk2]

As far as I can tell, very much standard build.

[shawnlaffan]

They might need some extra flags. The lapack build and packing setups are below. There is nothing disabling lapacke.

FWIW, MSYS2 package lapacke separately. https://github.com/msys2/MINGW-packages/blob/master/mingw-w64-lapack/PKGBUILD

build-extlibs/build.sh

Lines 1210 to 1222 in d22291c

	# ----------------------------------------------------------------------------
	lapack-*)
	cd $WRKDIR/$PACK
	mkdir MY_BUILD
	cd MY_BUILD
	xxrun cmake -G 'MSYS Makefiles' -DCMAKE_INSTALL_PREFIX=$OUT -DBUILD_SHARED_LIBS=OFF -DBUILD_STATIC_LIBS=ON -DBUILD_DEPRECATED=ON ..
	xxrun make
	xxrun make install
	###hack needed for static build
	sed -i 's,-lblas,-lblas -lgfortran -lquadmath,' $OUT/lib/pkgconfig/blas.pc
	sed -i 's,-llapack,-llapack -lblas -lgfortran -lquadmath,' $OUT/lib/pkgconfig/lapack.pc
	;;

build-extlibs/pack.pl

Lines 854 to 868 in d22291c

	'lapack-' => {
	'files' => [],
	'trees' => [
	['bin', 'c\bin', '-config(\.bat)?$'],
	['bin', 'c\bin', '\.dll$'],
	['lib', 'c\lib', '\.a$'],
	['lib\pkgconfig', 'c\lib\pkgconfig', '\.pc$'],
	['include', 'c\include', '\.h$'],
	],
	'licenses' => ['LICENSE'],
	'licdir' => 'licenses\liblapack',
	'urls' => [
	['Homepage', 'http://www.netlib.org/lapack/'],
	],
	},

[shawnlaffan]

lapacke might be off by default.
https://github.com/Reference-LAPACK/lapack/blob/4b3d8a46435f57462075f7c8f33b9bd1cf29a1dc/CMakeLists.txt#L344

[mohawk2]

Ah, my mistake! And there's also the matter of the headers, which I don't think we're getting yet.

[shawnlaffan]

It's easy enough to add -DLAPACKE=ON to the cmake call. The libs and headers will be picked up once built.

Will give it a go when I next run an extlibs update.

[mohawk2]

Great! By the way, here's a real stretch ask: what do you think of including OpenCL, along the lines of https://github.com/KhronosGroup/OpenCL-Guide/blob/main/chapters/getting_started_windows.md ? I'm having a go at it with MinGW and my place-with-space, which is blowing up cmake.

[shawnlaffan]

If there is a clear need then we can consider other packages, especially if they come via PRs. If they are a huge amount of effort then it comes down to available time.

[mohawk2]

Fair enough, obviously! If I were confident enough that I could get a dev environment going for this specific system, I'd have a go myself. Or even if there were CI.

[shawnlaffan]

Do you mean the Strawberry Perl build system? It is set up to use docker - https://github.com/StrawberryPerl/spbuild

And FWIW, MSYS2 is usually a good source of patches and build steps.
https://github.com/msys2/MINGW-packages/blob/master/mingw-w64-opencl-headers/PKGBUILD

It won't fix paths with spaces, but can the build system be set up to work in a dir without spaces?

[mohawk2]

I'm looking to make PDL::LinearAlgebra use LAPACKE/CBLAS very soon. This is with a view to then switching it to use FlexiBLAS which allows runtime selection of which BLAS etc to use, which is probably more of a concern on Linux than Windows.

Therefore, please could you enable the building and especially distributing with the C headers and enabling libs?

[shawnlaffan]

I'll be updating the extlibs for perl 5.44 soonish. These are on the list.

[shawnlaffan]

Added in #71

I'll close this now but we can re-open if issues arise with the downstream builds.