[QE-users] energy calculation

Pooja Vyas poojavyas1251995 at gmail.com
Thu Jan 9 12:14:45 CET 2020


Respected sir,
I understand completely that 2*2*2 takes time, but in my case, the
iteration doesn't even start.
Though I shall perform convergence, but can you suggest any specific
numbers for both these parameters (cutoff and k-point) suitable for my
input?

On Thu, Jan 9, 2020 at 4:40 PM Tone Kokalj <tone.kokalj at ijs.si> wrote:

> Dear Pooja,
>
> All seems fine. Note that calculation of (2x2x2) supercell takes
> considerably longer than that of the (1x1x1) unit cell.
>
> Are you sure you need that high cutoff energy and that dense k-point
> grid? If you reduce these two then the calculation will run faster.
>
> Best regards,
> Tone Kokalj
> --
> Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
> (tel: +386-1-477-3523 // fax: +386-1-251-9385)
>
>
> On Thu, 2020-01-09 at 15:13 +0530, Pooja Vyas wrote:
> > Following is my input file:
> > &control
> >     calculation = 'scf',
> >     prefix = '9.1334'
> >     tstress= .true.
> >     tprnfor= .true.
> >     outdir = '/home/user/cao.oct/'
> >     pseudo_dir = '/home/user/cao.oct/pseudo/'
> >  /
> >  &system
> >     ibrav =  0,
> >     celldm(1)=9.1334,
> >     nat =  64,
> >     ntyp = 2,
> >     ecutwfc = 100,
> > /
> > &electrons
> >     mixing_beta = 0.7
> >
> > /
> >
> > ATOMIC_SPECIES
> >
> > Ca 40.078  Ca.pbe-nsp-van.UPF
> > O 15.999 O.pbe-van_ak.UPF
> >
> > ATOMIC_POSITIONS (angstrom)
> >    Ca    2.4165926060    2.4165926060    0.0000000000
> >    Ca    0.0000000000    0.0000000000    0.0000000000
> >    Ca    2.4165926060    0.0000000000    2.4165926060
> >    Ca    0.0000000000    2.4165926060    2.4165926060
> >     O    4.8331852120    4.8331852120    2.4165926060
> >     O    2.4165926060    2.4165926060    2.4165926060
> >     O    4.8331852120    2.4165926060    4.8331852120
> >     O    2.4165926060    4.8331852120    4.8331852120
> >    Ca    2.4165926060    2.4165926060    4.8331852120
> >    Ca    0.0000000000    0.0000000000    4.8331852120
> >    Ca    2.4165926060    0.0000000000    7.2497778180
> >    Ca    0.0000000000    2.4165926060    7.2497778180
> >     O    4.8331852120    4.8331852120    7.2497778180
> >     O    2.4165926060    2.4165926060    7.2497778180
> >     O    4.8331852120    2.4165926060    9.6663704240
> >     O    2.4165926060    4.8331852120    9.6663704240
> >    Ca    2.4165926060    7.2497778180    0.0000000000
> >    Ca    0.0000000000    4.8331852120    0.0000000000
> >    Ca    2.4165926060    4.8331852120    2.4165926060
> >    Ca    0.0000000000    7.2497778180    2.4165926060
> >     O    4.8331852120    9.6663704240    2.4165926060
> >     O    2.4165926060    7.2497778180    2.4165926060
> >     O    4.8331852120    7.2497778180    4.8331852120
> >     O    2.4165926060    9.6663704240    4.8331852120
> >    Ca    2.4165926060    7.2497778180    4.8331852120
> >    Ca    0.0000000000    4.8331852120    4.8331852120
> >    Ca    2.4165926060    4.8331852120    7.2497778180
> >    Ca    0.0000000000    7.2497778180    7.2497778180
> >     O    4.8331852120    9.6663704240    7.2497778180
> >     O    2.4165926060    7.2497778180    7.2497778180
> >     O    4.8331852120    7.2497778180    9.6663704240
> >     O    2.4165926060    9.6663704240    9.6663704240
> >    Ca    7.2497778180    2.4165926060    0.0000000000
> >    Ca    4.8331852120    0.0000000000    0.0000000000
> >    Ca    7.2497778180    0.0000000000    2.4165926060
> >    Ca    4.8331852120    2.4165926060    2.4165926060
> >     O    9.6663704240    4.8331852120    2.4165926060
> >     O    7.2497778180    2.4165926060    2.4165926060
> >     O    9.6663704240    2.4165926060    4.8331852120
> >     O    7.2497778180    4.8331852120    4.8331852120
> >    Ca    7.2497778180    2.4165926060    4.8331852120
> >    Ca    4.8331852120    0.0000000000    4.8331852120
> >    Ca    7.2497778180    0.0000000000    7.2497778180
> >    Ca    4.8331852120    2.4165926060    7.2497778180
> >     O    9.6663704240    4.8331852120    7.2497778180
> >     O    7.2497778180    2.4165926060    7.2497778180
> >     O    9.6663704240    2.4165926060    9.6663704240
> >     O    7.2497778180    4.8331852120    9.6663704240
> >    Ca    7.2497778180    7.2497778180    0.0000000000
> >    Ca    4.8331852120    4.8331852120    0.0000000000
> >    Ca    7.2497778180    4.8331852120    2.4165926060
> >    Ca    4.8331852120    7.2497778180    2.4165926060
> >     O    9.6663704240    9.6663704240    2.4165926060
> >     O    7.2497778180    7.2497778180    2.4165926060
> >     O    9.6663704240    7.2497778180    4.8331852120
> >     O    7.2497778180    9.6663704240    4.8331852120
> >    Ca    7.2497778180    7.2497778180    4.8331852120
> >    Ca    4.8331852120    4.8331852120    4.8331852120
> >    Ca    7.2497778180    4.8331852120    7.2497778180
> >    Ca    4.8331852120    7.2497778180    7.2497778180
> >     O    9.6663704240    9.6663704240    7.2497778180
> >     O    7.2497778180    7.2497778180    7.2497778180
> >     O    9.6663704240    7.2497778180    9.6663704240
> >     O    7.2497778180    9.6663704240    9.6663704240
> >
> > CELL_PARAMETERS (alat)
> > 2.0 0.0 0.0
> > 0.0 2.0 0.0
> > 0.0 0.0 2.0
> >
> > K_POINTS (automatic)
> >   11 11 11 1 1 1
> >
> > But the iteration does not start and the calculation doesn't proceed
> > and gets stuck at the following point:
> >     Dense  grid:   823321 G-vectors     FFT dimensions: ( 120, 120,
> > 120)
> >
> >      Estimated max dynamical RAM per process >     794.24 MB
> >
> >      Estimated total dynamical RAM >      31.02 GB
> >
> >      Check: negative core charge=   -0.000001
> >
> >      Initial potential from superposition of free atoms
> >
> >      starting charge  511.82530, renormalised to  512.00000
> >
> >      negative rho (up, down):  5.921E-03 0.000E+00
> >      Starting wfcs are  448 randomized atomic wfcs
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