[Pw_forum] Time of phonon calculation

[TuanAnh Pham]

Maybe because you use too many k-points, I guess. Try with a smaller number
of k-points first,
I've done a test with your input with 2 2 2 k-points and it's very fast.

Hope this helps,

On Fri, May 15, 2009 at 4:24 AM, Ruslan S. Yagufarov
<yagufarov at phys.tsu.ru>wrote:

> Hello, dear Pwscf users,
>
> I have a question about phonon dispersion calculation in Ni2MnGa.
> The problem is that it takes too much time and the iteration procedure does
> not converge at all. I am tried to use various parameters, but without any
> success. After doing 100 iterations,
> Maybe I'm using wrong threshholds??? (my .scf and .ph inputs are attached
> below). As it seems to me? according to the previous post on this forum the
> everything is right.
>
> Actually, the questions are:
>
> 1)How much time does it usually take to calculate correct phonon dispersion
> for a system with only 4 atoms (like Ni2MnGa) in the case of non-parallel
> execution (assuming that you are using quite good computer with 2
> processors
> and all parameters are good). Is it possible to have more than 50 hours
> calculation???
>
> 2)Can anybody tell me what is wrong with this:
>
> SCF calculation
>
>  &control
> calculation = 'scf',
> restart_mode='from_scratch',
> prefix='Ni2MnGa',
> pseudo_dir = '/home2/ruslan/q/pseudo',
> outdir= '/home2/ruslan/out'
> tprnfor=.true.
> tstress=.true.
> /
> &system
> ibrav=  2, celldm(1) =11.011  , nat =  4, ntyp = 3,
> ecutwfc = 27.0,  ecutrho =350 , degauss=0.01
> smearing = 'mp', occupations = 'smearing',  nspin = 2,
> starting_magnetization(2) = 1.0
> starting_magnetization(1) = 0.3
> starting_magnetization(3) = 0
> /
> &electrons
> /
> ATOMIC_SPECIES
> Ni     58.69      Ni.pbe-nd-rrkjus.UPF
> Mn     54.93        Mn.pbe-sp-van.UPF
> Ga     69.72        Ga.pbe-nsp-van.UPF
> ATOMIC_POSITIONS alat
> Ni       0.25 0.25 0.25
> Ni      -0.25 -0.25 -0.25
> Mn      -0.50 -0.50 -0.50
> Ga       0.00 0.00 0.00
> K_POINTS automatic
> 8 8 8 0 0 0
>
> PH calculation
>
> &inputph
>  prefix='Ni2MnGa',
>  ldisp=.true.,
>  alpha_mix(1)=0.1,
>  tr2_ph=1.0d-12,
>  nq1=4,
>  nq2=4,
>  nq3=4,
>  amass(1)=58.6943,
>  amass(2)=54.938049,
>  amass(3)=69.72,
>  outdir='/home2/ruslan/out',
>  fildyn='/home2/ruslan/out/ni2mnga.dynX',
> /
>
> Thank you!
> Best regards, Ruslan
> Tomsk State University, Institute of Material Science SB RAS
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>



-- 
Tuan Anh Pham
Graduate Student
University of California, Davis
Phone: 530-752-0957
Homepage: http://angstrom.ucdavis.edu/
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