[Pw_forum] GIPAW acceleration

Davide Ceresoli davide.ceresoli at cnr.it
Thu Jul 13 18:29:46 CEST 2017

Dear Yasser,
     how many atoms? how many k-points? I/O can always be
the reason, but in my experience if the system is very
large, time is dominated by computation, not I/O.
You should get some speedup if diagonalization='cg' in

Anyway, if I have time, I will introduce a "disk_io" variable
in the input file, to try to keep more data in memory instead
that on disk.

Best regards,

On 07/13/2017 10:02 AM, Yasser Fowad AlWahedi wrote:
> Dear GIPAW users,
> For nmr shifts calculations, I am suffering from the extreme slowness of GIPAW
> nmr shifts calculations.  I have noticed that GIPAW write off the results
> frequently for restart purposes. In our clusters we have mechanical hard drives
> which stores the off data for. Could that be a reason for its slowness?
> Yasser Al Wahedi
> Assistant Professor
> Khalifa University of Science and Technology

   Davide Ceresoli
   CNR Institute of Molecular Science and Technology (CNR-ISTM)
   c/o University of Milan, via Golgi 19, 20133 Milan, Italy
   Email: davide.ceresoli at istm.cnr.it
   Phone: +39-02-50314276, +39-347-1001570 (mobile)
   Skype: dceresoli

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