[gpaw-users] MPI-Scalapack library for Python

[Kuisma, Mikael]

Hi!

I added some Scalapack/blacs routines while implementing the LCAO-TDDFT for GPAW and it was somewhat cumbersome. Also, the API we have in GPAW is somewhat tedious to use at the moment: we have a lot of code to handle ScaLAPACK and LAPACK calls as different cases. So I would vote for writing a general Python-Scalapack library (instead that you take code from GPAW to your Python/C code).  We could make this library transparent, so it would work also without ScaLAPACK performing serial linear algebra..

ScaPACK does not parallize as well as I would like it to parallelize.  With a library wrapper, one could also try other libraries (for eigensolvers, there are at least more parallel solvers than ScaLAPACK).

One more remark regarding GPAW: I always resist adding external libraries to GPAW, so if one does a python with c-bindings library, I think it would make sense to embed that Python and C-code directly to GPAW repository. The end users do not like install new dependencies every time the version number increases by 0.1. (I wish that we should also provide basic working installation of libxc and libvdwxc as well in our repository, with option to link to external libraries).

I do not know about licencing issues that well, but as far as I think, it should be ok to take code from GPAW (GPL), if your code is also GPL and make your code available.

BR,
Mikael Kuisma

Academy of Finland Post Doc

Nanoscience Center
Department of Chemistry
University of Jyväskylä
P.O. Box 35
FIN-40014 University of Jyväskylä
Finland

E-mail: mikael.j.kuisma (at) jyu.fi
Phone: +358 40 077 4114

https://scholar.google.se/citations?user=w0eP9esAAAAJ

Visiting address: NSC, 3rd floor, YN320

________________________________________
Lähettäjä: gpaw-users-bounces at listserv.fysik.dtu.dk [gpaw-users-bounces at listserv.fysik.dtu.dk] käyttäjän marc via gpaw-users [gpaw-users at listserv.fysik.dtu.dk] puolesta
Lähetetty: 21. syyskuuta 2017 14:10
Vastaanottaja: gpaw-users at listserv.fysik.dtu.dk
Kopio: Peter Koval
Aihe: [gpaw-users] MPI-Scalapack library for Python

Dear Gpaw developers,

We are actually developing a python code to perform efficient TDDFT
calculation with LCAO. Our program can read DFT data from different code
such as Siesta, OpenMX, Pyscf and GPAW (with some limitations for the
moment).
We would like to parallelize our code using MPI and Scalapack but we
could not find any library in python that wrap both MPI and Scalapack.
Looking to the GPAW code, we have seen that you wrote your own wrapper
for MPI-Saclapack. My question is the following, would it be difficult
to modify your MPI wrapper to use it in our code? Is it feasible from a
license point of view?
Do you think it could be feasible to write a general python wrapper for
MPI and Scalapack in an other library using your implementation?

Best regards,
Marc Barbry
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