Is there a limit for the number of cores which can run with NPAR = No. cores?

Problems running VASP: crashes, internal errors, "wrong" results.


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hipertrofia
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Is there a limit for the number of cores which can run with NPAR = No. cores?

#1 Post by hipertrofia » Mon Apr 28, 2014 7:25 pm

I am running a hybrid functional calculation, for which NPAR needs to be set to the number of cores (default). I am running a PBE calculation to preconverge the wave function before running a HSE calculation on top of it. In order to have the same basis set upon restart, I also leave the default NPAR set for the PBE calculation. My system is relatively large, with 1040 electrons. When I run this calculation with many cores (I have tried 256 and 192, allocated in 16-core nodes) I get a segmentation fault - even for the PBE calculation. If I run exactly the same calculation with 64 cores distributed in 4 16-core nodes, the PBE calculation runs with no problems.

Hence my question - is there a hard limit to the number of cores that can be used with the default NPAR? If so, is there a way to estimate which value would be optimal?
Last edited by hipertrofia on Mon Apr 28, 2014 7:25 pm, edited 1 time in total.

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Is there a limit for the number of cores which can run with NPAR = No. cores?

#2 Post by admin » Wed Jul 09, 2014 1:33 pm

There is no limit to the number of cores.
Last edited by admin on Wed Jul 09, 2014 1:33 pm, edited 1 time in total.

YuQiang Gao

Re: Is there a limit for the number of cores which can run w

#3 Post by YuQiang Gao » Tue Sep 09, 2014 4:36 am

I also have the same question.
At last, I use the default NPAR set,it runs with no problem.
But I get a warnning I can't get the DOSCAR and PDOS for the NPAR/=1.

zzhlax
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Re: Is there a limit for the number of cores which can run w

#4 Post by zzhlax » Tue Dec 02, 2014 5:28 am

you can use LORBIT.

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