[Pw_forum] Silent Calculations

Stefano de Gironcoli degironc at sissa.it
Fri Aug 8 17:03:53 CEST 2008


there should be no incompatibility between shifted grids and phonon 
calculations.
stefano

Subhradip Ghosh wrote:
> Dear Eyvaz,
>
> It would be nice if you explain why phonons and shifted k-mesh are
> incompatible. Hiowever, I have used shifted k-mesh for phonon calculations
> and didn't find anything unusual for the systems I tried so far.
>
> Regards,
>
> Subhradip
>
>
>
>   
>> Dear Miguel,
>>
>> It might be I am wrong, but I am not sure phonons and shifted k-points are
>> compatible.
>> At least, I never did it (i.e. used only unshifted k-vectors).
>>
>> As concerns your joke about August, well, it is pretty good. And add
>> September, October, November, etc.
>> This one recalled me a famous math problem ...
>>
>> Bests,
>> Eyvaz.
>>
>> -------------------------------------------------------------------
>> Prof. Eyvaz Isaev,
>> Theoretical Physics Department, Moscow State Institute of Steel & Alloys,
>> Russia,
>> Department of Physics, Chemistry, and Biology (IFM), Linkoping University,
>> Sweden
>> Condensed Matter Theory Group, Uppsala University, Sweden
>> Eyvaz.Isaev at fysik.uu.se, isaev at ifm.liu.se, eyvaz_isaev at yahoo.com
>>
>>
>> --- On Fri, 8/8/08, Miguel Martínez <miguel.martinez at ehu.es> wrote:
>>
>>     
>>> From: Miguel Martínez <miguel.martinez at ehu.es>
>>> Subject: [Pw_forum] Silent Calculations
>>> To: "PWscf Forum" <pw_forum at pwscf.org>
>>> Date: Friday, August 8, 2008, 1:28 PM
>>> Dear everybody,
>>>
>>> I've been running into a few issues as of late, when
>>> running some
>>> calculations, it seems the calculations have stalled for a
>>> pretty long
>>> period of time.
>>>
>>> The one that troubles me less, taking into account that
>>> it's pretty
>>> expensive, is an electron-phonon calculation. This is a
>>> pretty large
>>> system (20 atoms in the primitive cell) and computing the
>>> phonons at
>>> gamma took ages (well two days using 4 processors). It
>>> would be great
>>> if some output were written just to remind you the code is
>>> still
>>> working, maybe something related to convergence. But I find
>>> somewhat
>>> disturbing that no line was written since the electron
>>> phonon
>>> calculation began.
>>>
>>> My other issue is a very similar stalling in a Raman
>>> calculation. No,
>>> it's not the same structure. Here, I lack from
>>> experience, since this
>>> is the first Raman calculation I've done outside the
>>> examples.
>>>
>>> Self-consistent input is:
>>>  &control
>>>     calculation='scf'
>>>     restart_mode='from_scratch',
>>>     prefix='sih4',
>>>     tstress = .true.
>>>     tprnfor = .true.
>>>     pseudo_dir = '/home/wmbmacam/pseudo/',
>>>     outdir='/scratch/wmbmacam/fdd2-raman/'
>>>  /
>>>  &system
>>>     ibrav= 10, celldm(1) = 12.65898481, celldm(2) =
>>> 1.07100858,
>>> celldm(3) = 0.621208699, nat=10, ntyp= 2,
>>>     ecutwfc = 55.0
>>>     nr1= 72, nr2= 72, nr3= 72
>>>  /
>>>  &electrons
>>>     conv_thr = 1.0d-8
>>>     mixing_beta = 0.7
>>>  /
>>> ATOMIC_SPECIES
>>>  Si  28.0855 Si.pbe-rrkj.UPF
>>>   H   1.0079  H.pbe-vbc.UPF
>>> ATOMIC_POSITIONS {crystal}
>>> Si 0.614368447799 0.385631552201 0.614368447799
>>> Si 0.864368447799 0.635631552201 0.864368447799
>>> H  0.442372877617 0.836174882136 0.364427192728
>>> H  0.364427192728 0.357025047520 0.442372877617
>>> H  0.892974952480 0.885572807272 0.413825117864
>>> H  0.413825117864 0.807627122383 0.892974952480
>>> H  0.378768583324 0.338682246661 0.003482898532
>>> H  0.003482898532 0.279066271483 0.378768583324
>>> H  0.970933728517 0.246517101468 0.911317753339
>>> H  0.911317753339 0.871231416676 0.970933728517
>>> K_POINTS {automatic}
>>>  12 12 12  1 1 1
>>>
>>>
>>> The phonon input is:
>>>
>>> phonons of Sih4 at Gamma
>>>  &inputph
>>>   tr2_ph=1.0d-16,
>>>   prefix='sih4',
>>>   epsil=.true.,
>>>   trans=.true.,
>>>   lraman=.true.,
>>>   elop=.true.,
>>>   amass(1)=28.0855,
>>>   amass(2)=1.00794,
>>>   outdir='/scratch/wmbmacam/fdd2-raman/',
>>>   fildyn='sih4.dynG',
>>>   fildrho='sih4.drho',
>>>  /
>>> 0.0 0.0 0.0
>>>
>>>
>>> The calculations stalled right after the effective charges
>>> calculations.
>>> After that, it spent 24 hours without writing anything (it
>>> needed 10
>>> hours to compute the effective charges). No convergence, no
>>> threshold,
>>> no crashes, no nothing.
>>>
>>> Is this behaviour normal? Or are my compiled binaries just
>>> telling me I
>>> should stop bothering them in August?
>>>
>>> Finally, I just wanted to note that the amasses in example
>>> 15 are
>>> seemingly wrong. While the masses in the scf run are fine,
>>> the ones
>>> used in the phonon calculations correspond to GaAs instead
>>> of AlAs.
>>>
>>> Regards,
>>>
>>> Miguel
>>>
>>> --
>>> ----------------------------------------
>>> Miguel Martínez Canales
>>>    Dto. Física de la Materia Condensada
>>>    UPV/EHU
>>>    Facultad de Ciencia y Tecnología
>>>    Apdo. 644
>>>    48080 Bilbao (Spain)
>>> Fax:  +34 94 601 3500
>>> Tlf:  +34 94 601 5326
>>> ----------------------------------------
>>>
>>>  "If you have an apple and I have an apple and
>>>  we exchange these apples then you and I will
>>>  still each have one apple. But if you have an
>>>  idea and I have an idea and we exchange these
>>>  ideas, then each of us will have two ideas."
>>>
>>>  George Bernard Shaw
>>>
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>>>       
>>
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>>     
>
>
> ************************************************************************
>               Dr. Subhradip Ghosh
>               Assistant Professor
>               Department of Physics
>             Indian Institute of Technology
>                Guwahati,Assam-781039
>                     India
>                E-mail:subhra at iitg.ernet.in
>                Phone: +91 361 2582717(O)
>                       +91 361 2584717(R)
>                 Fax:  +91 361 2582749 (Physics)
>                       +91 361 2690762 (General)
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>
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