[QE-developers] Incompatible FFT grid in ph.x calculation

[Paolo Giannozzi]

On Fri, Aug 14, 2020 at 2:51 PM Xiao Zhang <xiaozha at umich.edu> wrote:

I realized that in 6.6, an additional line shows: Fft bands division: nmany
> = 1 (line 15). Not sure if this means anything or not?
>

it doesn't.

Apparently the check on fractional translations being commensurate with the
real-space grid is a little bit too strict. Not sure how to fix it in a
safe way, though

Paolo


> Thanks!
> Best!
> Xiao
>
> On Fri, Aug 14, 2020 at 8:31 AM Paolo Giannozzi <p.giannozzi at gmail.com>
> wrote:
>
>> It would be useful to see the scf output for v.6.5 as well
>>
>> Paolo
>>
>> On Fri, Aug 14, 2020 at 9:14 AM Xiao Zhang <xiaozha at umich.edu> wrote:
>>
>>> Dear QE developers,
>>>
>>> I'm sending the email asking about an error I get from the phonon
>>> calculations in the 6.6 version of quantum espresso. I'm trying to run
>>> phonon calculation for 2H SiC and have the scf run finished with no
>>> problem, but when I run phonon calculation following that, I received an
>>> incompatible FFT grid error. This happened only with the new version of QE
>>> while using the exact same input, QE 6.5 works fine and provides output. I
>>> was wondering if this is something we expect? (I do realize there is one
>>> potentially relevant tag on the release note under "fixed")
>>>
>>> I attached one example just in case it might help: This is 2H-SiC and I
>>> attached the input and output from scf, input and output from ph.x from
>>> both 6.5 and 6.6. The k-points and cutoffs are reduced for quick tests, but
>>> converged k-points and cutoffs show the same issue. The structure is
>>> relaxed within QE, and the PP used is ONCV-PBE. I'm a bit confused why this
>>> is seen in phonon calculation but not the scf calculation? I assumed that
>>> if it's a problem of my input structure, I should've seen a problem in
>>> both? Any hint or suggestions would be very helpful!
>>>
>>> Thanks a lot!
>>> Best!
>>> Xiao Zhang
>>> Department of Materials Science and Engineering
>>> University of Michigan, Ann Arbor
>>>
>>> _______________________________________________
>>> developers mailing list
>>> developers at lists.quantum-espresso.org
>>> https://lists.quantum-espresso.org/mailman/listinfo/developers
>>>
>>
>>
>> --
>> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
>> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
>> Phone +39-0432-558216, fax +39-0432-558222
>>
>>

-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
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