[Wannier] wannier90 + vasp initial projections parallelism

[Nicola Marzari]

Hi Aron,


but without overlaps you won't have MLWFs? I guess you are just trying
to do "poor man's Wannier" via projections?

Still, might be worth trying quantum-espresso, since those calculations
are parallelized. All plane wave codes are fairly similar, at the end...

I'll be in ETHZ next week (wed/thu), so we could always catch up there.

			nicola


On 13/01/2015 11:55, Aron Szabo wrote:
> Dear Wannier90 developers,
>
> I'm using vasp 5.3 and wannier90 2.0. I've noticed that the calculation
> of the initial projections for the wannierization in vasp is sequential,
> it doesn't speed up with the increasing number of cpu-s. For large
> systems I'm calculating separately smaller sets of projections to
> emulate some parallelism, but there is a huge overhead from calculating
> the overlaps first in each case. It can take 1-2 days just to start
> calculating the projections when I have 2-300 atoms (1-2000 bands). So
> generating the projections can take more time than the actual
> wannierization. If the calculation of the overlaps could be somehow
> switched off, it would already solve this problem practically, because
> then the calculation of the projections would scale nicely, and the
> overlaps could be calculated in a separate run. I'm not good in fortran,
> so I'm asking you whether it could be done maybe by just commenting out
> a few lines somewhere either in vasp's or wannier90's code, and if so,
> where is it exactly? I'm also interested if it is planned at all to
> parallelize the wannierization sometimes in the future, or is the
> problem itself something that's not possible to parallelize efficiently?
>
> Thanks in advance,
> Aron Szabo
> PhD student at IIS, ETH Zurich
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-- 

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Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL