[QE-users] SCF not converging in QE6.3 (but it does so in, QE6.0)

Pietro Delugas pdelugas at sissa.it
Thu Jan 31 18:20:01 CET 2019


ehm ...

I should have read the guide before answering, sorry Guido,

I surely would have been more helpfull

following the indications that the  cineca module qe/6.3_knl   prints 
out when it is loaded  and using the bind-cpu option of srun

srun --bind-cpu=cores pw.x < pwin > pwout

the 6.3  works smoothly also for cpu-per-task=2  and tasks-per-node=68

Pietro

On 31/01/19 14:41, Guido Fratesi wrote:
> Dear Pietro, Paolo and Davide,
>
> thank you for your hints. Indeed by changing the number of CPUs the 
> calculation *may* converge also with QE6.3. For example:
>
> 2pools-x-34cpus-x-2omp (ie #MPIxOpenMP cores = #cpus)
> 2pools-x-8cpus-x-2omp
> 6pools-x-8cpus-x-2omp
>
> are OK, but
>
> 2pools-x-68cpus-x-1omp (ie #MPIxOpenMP cores = #cpus)
>
> does not converge again, although I'm not asking for more tasks than 
> cpus (see Pietro's comment). Also, KNL nodes in A2 should support 
> hyperthreading (4x) 
> https://wiki.u-gov.it/confluence/display/SCAIUS/UG3.1%3A+MARCONI+UserGuide#UG3.1:MARCONIUserGuide-SystemArchitecture 
> so I would not expect that asking for a number of threads that is 
> twice the number of allocated cpu's would be a problem - nor it is for 
> QE6.0 and for the inputs with the molecule/surface.
>
> I though this could be related to the size of the system since I had 
> no problems with the heavier molecule/surface case; however, the 
> problem is also present for larger, clean-Au(111), unit cells.
>
> I can now circumvent the issue, thank you. I'd also be curious to know 
> what is the reason...
>
> Guido
>
>
>
>
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