[Debichem-devel] Bug#935994: Bug#935994: nwchem: NWChem compiled with long int lapack/blas interface?

[Michael Banck]

Hi Giacomo,

sorry, I apparently missed your mail initially.

On Wed, Aug 28, 2019 at 08:42:21PM +0200, Giacomo Mulas wrote:
> I am a long time NWChem (ab)user.  I always have to compile NWChem myself,
> instead of using the binary version provided by debian, because for large
> enough molecules matrices become too big for the 32 bit int interface, and 
> only run if NWChem was compiled with a 64 bit int lapack/blas.
> I understand the need to provide a version of NWChem in debian that works
> with free libs available in debian as well, hence the need (so far) to 
> compile it using the 64 to 32 bit conversion of ints on 64 bit machines.
> However, lapack and blas libs with 64 bit integer interfaces just appeared
> on debian experimental, and have been available for some time in the 
> non-free (but packaged in non-free) Intel MKL libs.

I don't follow it closely, are you saying that both the refblas/lapack
packages now provide a 64bit int interface, and MKL? Or just MKL?

> Apparently, this would require limited changes in the debian/rules file.
> Would you consider building (also) such a version of nwchem, compiled with
> long int blas/lapack libs? 

Unless there are considerable downsides (are there?) I would not mind
switching the nwchem packaging to a 64bit int build using blas/lapack
libraries from main.

Regarding mkl, my current, initial opinion is that we would welcome
patches to make it possible to rebuild nwchem for MKL without source
changes (via some DEB_BUILD_OPTIONS or other external flags), but
building nwchem twice and once for MKL would (I believe) mean the source
package would have to move into contrib as it build-depended on a
non-free package.

Does anybody else want to chime in here and offer their opinion?


Michael