[QE-users] Very Complex Crystal?

[Pietro Bonfa]

Dear Stephen,

is your problem due to memory allocations or to the time required to
reach convergence?

In the latter case, the only thing I notice at first sight is that your
cell has c >> a, so you may want to adjust the k points mesh
accordingly, by reducing the number of points along c*, unless you have
good reasons to avoid that. Anyway, that won't change the workload
dramatically.

Best regards,
Pietro


On 7/17/20 11:22 PM, Stephen Zhang wrote:
> Hi Everyone,
>
> I have a compound that has 56 atoms in the unit cell, and my computer
> cannot really seem to handle the computation load. Is there any advice
> anyone could give to lighten up the load? I've pasted my input file below.
>
> &control
>    calculation = 'vc-relax'
>    prefix = 'TaCuO'
>    outdir = './outdir'
>    pseudo_dir = '/home/stephen/qe-6.5/SSSP_precision_pseudos'
>    etot_conv_thr = 1e-6
>    forc_conv_thr = 1e-5
> /
> &system
>    ibrav=4, celldm(1)=11.878282169945129, celldm(3)=3.25176929077,
>    nat=58, ntyp=3,
>    ecutwfc=30,
>    ecutrho=300,
>    occupations='smearing', smearing='gaussian', degauss=0.05,
> /
> &electrons
>    mixing_beta = 0.3
>    conv_thr=1e-9
> /
> &ions
> /
> &cell
>    cell_dofree='ibrav'
> /
> ATOMIC_SPECIES
>   Ta 180.94788 Ta.pbe-spfn-kjpaw_psl.1.0.0.UPF
>   Cu 63.546 Cu.pbe-dn-kjpaw_psl.1.0.0.UPF
>   O 15.999  O.pbe-n-kjpaw_psl.1.0.0.UPF
>
> ATOMIC_POSITIONS {crystal_b}
>   Ta 2.2697 -3.6193 7.0178
>   Ta 4.2692 0.1560 17.2376
>   Ta 1.1433 1.6683 17.2376
>   Ta 5.1424 -1.6683 7.0178
>   Ta 2.0165 -0.1560 7.0178
>   Ta 4.0160 3.6193 17.2376
>   Ta 4.0160 3.6193 13.4219
>   Ta 2.0165 -0.1560 3.2021
>   Ta 5.1424 -1.6683 3.2021
>   Ta 1.1433 1.6683 13.4219
>   Ta 4.2692 0.1560 13.4219
>   Ta 2.2697 -3.6193 3.2021
>   Ta 0.0000 0.0000 10.2198
>   Ta 0.0000 0.0000 0.0000
>   Cu 1.5714 -2.7218 10.2198
>   Cu 3.1429 0.0000 0.0000
>   Cu 1.5714 2.7218 0.0000
>   Cu 1.5714 2.7218 10.2198
>   Cu 3.1429 0.0000 10.2198
>   Cu 1.5714 -2.7218 0.0000
>   O 3.8377 3.4813 15.3298
>   O 2.0468 -0.3794 5.1099
>   O 4.9338 -1.5829 5.1099
>   O 1.3520 1.5829 15.3298
>   O 4.2389 0.3794 15.3298
>   O 2.4480 -3.4813 5.1099
>   O 0.0000 0.0000 6.8969
>   O 0.0000 0.0000 17.1168
>   O 0.0000 0.0000 13.5428
>   O 0.0000 0.0000 3.3229
>   O 3.9228 3.1567 7.0677
>   O 2.3704 -0.4680 17.2876
>   O 4.6952 -1.8189 17.2876
>   O 1.5905 1.8189 7.0677
>   O 3.9153 0.4680 7.0677
>   O 2.3629 -3.1567 17.2876
>   O 2.3629 -3.1567 13.3720
>   O 3.9153 0.4680 3.1521
>   O 1.5905 1.8189 3.1521
>   O 4.6952 -1.8189 13.3720
>   O 2.4490 -3.9369 1.1547
>   O 4.6339 0.1525 11.3745
>   O 0.9579 1.3542 11.3745
>   O 5.3278 -1.3542 1.1547
>   O 1.6518 -0.1525 1.1547
>   O 3.8367 3.9369 11.3745
>   O 3.8367 3.9369 19.2850
>   O 1.6518 -0.1525 9.0651
>   O 5.3278 -1.3542 9.0651
>   O 0.9579 1.3542 19.2850
>   O 4.6339 0.1525 19.2850
>   O 2.4490 -3.9369 9.0651
>   O 3.1429 -1.8145 2.8338
>   O 3.1429 1.8145 13.0536
>   O 3.1429 1.8145 17.6059
>   O 3.1429 -1.8145 7.3861
>   O 3.9228 3.1567 3.1521
>   O 2.3704 -0.4680 13.3720
>
> K_POINTS (automatic)
>   8 8 8 0 0 0
>
> Thanks,
> Stephen
>
>
> --
> /University of California, Berkeley/
> /Department of Letter and Sciences/
>
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