[Pw_forum] Very long time of computation

[Eyvaz Isaev]

Hi,

For 56 atoms and 8x8x8 q-points it is OK. You can
decrease ecutwfc down to 30Ry. Much more you can gain 
using just the Gamma point (1 1 1 0 0 0).
Your calculations will be more time demanding if you
turn to spin-polarized case.
Even for parallel calculations it will take time.

Best regards,
Eyvaz. 
P.S. Besides, you forgot ecutrho parameter which is
important for US pseudopotentials.


--- Jun-jun Yang <yang_jun-jun at hotmail.com> wrote:

> Hi,
> 
> I'm a newbie user of pwscf, and working on total
> energy calculation of 
> chromite mineral as
> my first step for getting familiar with the program.
> But when I run the 
> program, it looks like
> stpping at wavefunction calculation and seems
> endless.
> 
> starting charge 543.97604, renormalized to 544.00000
> Starting wfc are atomic
> 
> The longest time it stopped (maybe still running)
> here was over 5 hours on 
> one processor.
> The unit cell of the mineral has 56 atoms (Z=8) and
> crystal system is cubic. 
> I'm using USPP
> potential. Please refer to snippet of my input file
> below. Do I make 
> anything wrong? Is such
> a long computation time reasonable?
> 
> &control
>     calculation = 'scf'
>     restart_mode='from_scratch',
>     prefix='fecr2o4',
>     tstress = .true.
>     tprnfor = .true.
>     pseudo_dir = '../../pseudo/',
>     outdir = $HOME/temp/
> /
> &system
>     ibrav = 1, celldm(1) = 15.8321, nat = 56 , ntyp
> = 3,
>     ecutwfc = 40.0
> /
> &electrons
>     diagonalization = cg,
>     mixing_mode = 'plain',
>     mixing_beta = 0.7,
>     conv_thr =  1.0d-8
> /
> ATOMIC_SPECIES
> Fe  55.847  Fe.pbe-sp-van.UPF
> Cr  51.996  Cr.pbe-sp-van.UPF
> O   15.999   O.pbe-van_ak.UPF
> ATOMIC_POSITIONS angstrom
> Fe    0.00000    0.00000    0.00000
> Cr    5.23625    5.23625    5.23625
> O    3.23391    3.23391    3.23391
> ......
> ......
> 
> K_POINTS automatic
> 8 8 8  0 0 0
> 
> Please help and thanks in advance.
> 
> 
> Jun-jun Yang
> 
>
_________________________________________________________________
> Don’t just search. Find. Check out the new MSN
> Search! 
>
http://search.msn.click-url.com/go/onm00200636ave/direct/01/
> 
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
> 



	
		
__________________________________ 
Yahoo! Mail - PC Magazine Editors' Choice 2005 
http://mail.yahoo.com