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Re: RFC: Naming convention for ILP64 variant of BLAS/LAPACK




Le mardi 23 octobre 2018 à 14:12 +0000, Mo Zhou a écrit :
> On Mon, Oct 22, 2018 at 07:58:38PM +0200, Bastian Blank wrote:
> > On Mon, Oct 22, 2018 at 07:55:10PM +0200, Sébastien Villemot wrote:
> > > For BLAS/LAPACK implementations implemented in C, like OpenBLAS, they
> > > will be compiled using LP64, and not ILP64. Only integers exposed
> > > through the interface will be affected, through the use of appropriate
> > > types.
> > 
> > So you could also to a proper library transition and drop the support
> > for 32-bit indicies completely?
> 
> Completely dropping 32-bit-index version of BLAS/LAPACK for 64-bit
> architectures is a long way to go. We can keep 32-bit-index version and
> 64-bit-index version at the same time for a while and see if the
> 32-bit-version is really droppable.
> 
> This reminds me two points about wheter the 32-bit-index version is
> droppable. As far as I know, Debian (will) have these BLAS[1] providers:
> 
> (1) bin:libblas3  from  src:lapack
> (2) bin:libatlas3-base  from  src:atlas
> (3) bin:libopenblas-base  from  src:openblas
> (4) bin:libblis1  from  src:blis  [WIP]
> (5) bin:libmkl-rt  from  src:intel-mkl  [non-free]
> (6) bin:libnvblas9.1  from  src:nvidia-cuda-toolkit  [non-free] [2]
> 
> * I confirm these providers support 64-bit index in the API.
>   (2) (3) (4) (5)
> 
>   @Sebastien could you please confirm the status of 64-bit-index support
>   in lapack, i.e. (1) ?

Since the BLAS and LAPACK implementations provided by src:lapack are
pure Fortran code, my understanding is that it's just a matter of
compiling them with -fdefault-integer-8 to get 64-bit indexing.

This package also provides C interfaces (resp. CBLAS and LAPACKE).
LAPACKE provides the necessary type aliases to get 64-bit indexing.
Curiously, CBLAS does not seem to have that flexibility, and will
probably need some (reasonably simple) patching.

-- 
⢀⣴⠾⠻⢶⣦⠀  Sébastien Villemot
⣾⠁⢠⠒⠀⣿⡁  Debian Developer
⢿⡄⠘⠷⠚⠋⠀  http://sebastien.villemot.name
⠈⠳⣄⠀⠀⠀⠀  http://www.debian.org

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