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

On 2018-10-22 23:07, Mo Zhou wrote:

Are any
other packages likely to start wanting to use ILP64 ABIs? I guess it's
very much an 'HPC' sort of thing at the moment.

So yeah, some clarification in order I think, and an explanation of use-cases.

HPC is indeed a related use case. I don't know any other package that
would need such an ILP64 BLAS/LAPACK interface except for Julia.
Actually by default Julia uses ILP64 version of openblas instead of
LP64, see [julia-ilp64-default].

I don't have a strong opinion on what 64 bit policy Debian should push at this point in time. But I do have some experience with it on Cray. I found that FEniCS failed to run on multiple nodes using the standard (non-64) libraries (1 or 2 nodes was ok). But I got it running and scaling well up to 60 nodes (1440 processors) when I built against the 64 bit versions of the libraries (PETSc and others). It didn't really make sense since my mesh didn't have so many degrees of freedom that you would have thought 64 bit pointers were needed. But in practice there was a clear operational advantage to having the 64 bit libraries available.