[QE-users] Fw: Vc-relax file is keep on running
Gulshan Kumar
kumargulshan at iitgn.ac.in
Wed Sep 10 14:32:05 CEST 2025
Hi,
>From your input, the main reason your supercell is taking so long is that
you have increased the number of atoms to 120, which makes both the
electronic SCF and ionic relaxation much heavier than the unit cell. On top
of that, you are using an extremely small smearing (`degauss = 0.001`),
very tight electronic convergence (`conv_thr = 1e-8`), and a full
`vc-relax` (relaxing both ions and cell together). All of these slow things
down drastically. To speed up, the practical solution is to first relax
only the ions (`calculation='relax'`, `cell_dofree='none'`) until forces
are small, and then restart with `vc-relax` for the cell. Increase the
smearing to a more reasonable value (`degauss = 0.01–0.02`) and use
`smearing='cold'` or `'marzari'`, which will make SCF converge faster. You
can also loosen the electronic threshold temporarily (`conv_thr = 1e-6`)
during the initial relaxation, and then tighten it for the final run.
Additionally, try `diagonalization='cg'` in \&ELECTRONS and adjust
`mixing_beta` (0.2–0.3) if convergence is unstable.
So we have to go step by step.
Thank you.
On Wed, 10 Sep, 2025, 5:41 pm Gulshan Kumar, <kumargulshan at iitgn.ac.in>
wrote:
> Hi
> that’s expected behavior sometimes when you go from a small unit cell to a
> large doped supercell. A few likely causes: the system size (nat = 120)
> increases SCF / ionic work a lot, the very small smearing (degauss = 0.001)
> and very tight conv_thr make each SCF converge slowly, and a full vc-relax
> (cell + ions) on a large supercell is computationally heavy.
>
> Hope it helps.
>
> On Wed, 10 Sep, 2025, 5:33 pm Monika Srivastava via users, <
> users at lists.quantum-espresso.org> wrote:
>
>> Please find the attached file I am trying to vc-relax unit cell was
>> optimized in 30hrs but after making supercell with strontium doping it is
>> keep on going more than 120 hrs and still running without giving any error
>>
>> &CONTROL
>> calculation = "vc-relax"
>> max_seconds = 84600
>> prefix ="lsmo"
>> outdir ="./outdir_lsmo"
>> restart_mode = "from_scratch"
>> pseudo_dir =
>> "/net/pr2/projects/plgrid/plggkowalskigroup/Sandra_work/LSMO/pseudo"
>> etot_conv_thr = 1e-05
>> forc_conv_thr = 1e-04
>> disk_io = "high"
>> /
>>
>> &SYSTEM
>> ibrav = 0
>> nat = 120
>> ntyp = 4
>> nspin = 2
>> ecutwfc = 45
>> ecutrho = 180
>> occupations = "smearing"
>> smearing = "gaussian"
>> degauss = 0.001
>> starting_magnetization(1) = 0.00000e+00
>> starting_magnetization(2) = 2.00000e-01
>> starting_magnetization(3) = 0.00000e-01
>> /
>>
>> &ELECTRONS
>> conv_thr = 1.00000e-8
>> electron_maxstep = 500
>> mixing_beta = 2.5000000e-01
>> startingpot = "atomic"
>> startingwfc = "atomic+random"
>> diago_david_ndim = 4
>> /
>>
>> &IONS
>> ion_dynamics = "bfgs"
>> /
>>
>> &CELL
>> cell_dynamics = "bfgs"
>> cell_dofree = "all"
>> /
>>
>> ATOMIC_SPECIES
>> Mn 54.93805 mn_pbe_v1.5.uspp.F.UPF
>> O 15.99940 O.pbe-n-kjpaw_psl.0.1.UPF
>> La 138.90550 La.paw.z_11.atompaw.wentzcovitch.v1.2.upf
>> Sr 87.62 Sr_pbe_v1.uspp.F.UPF
>>
>> CELL_PARAMETERS (angstrom)
>> 11.2969865799 0.0000000000 0.0000000000
>> -5.6484932899 9.7834773644 0.0000000000
>> 0.0000000000 0.0000000000 13.5085849762
>>
>> ATOMIC_POSITIONS (crystal)
>> Mn 0.0000000000 0.0000000000 0.0000000000
>> Mn 0.0000000000 0.5000000000 0.0000000000
>> Mn 0.5000000000 0.0000000000 0.0000000000
>> Mn 0.5000000000 0.5000000000 0.0000000000
>> O 0.3333294689 0.8804080486 0.0833345577
>> O 0.1195919811 0.4529214501 0.0833345577
>> O 0.6195919514 0.4529214501 0.0833345577
>> O 0.8333294392 0.8804080486 0.0833345577
>> O 0.1195919439 0.9529213309 0.0833345577
>> O 0.3333294690 0.3804080188 0.0833345577
>> O 0.5470785498 0.6666705608 0.0833345577
>> O 0.0470785908 0.6666705608 0.0833345577
>> O 0.8333294391 0.3804080188 0.0833345577
>> O 0.0470785759 0.1666705459 0.0833345577
>> O 0.5470785499 0.1666705459 0.0833345577
>> O 0.6195919514 0.9529213309 0.0833345577
>> Sr 0.8333333731 0.6666666865 0.0833349600
>> Sr 0.3333333432 0.1666666716 0.0833349600
>> La 0.8333333731 0.1666666716 0.0833349600
>> La 0.3333333432 0.6666666865 0.0833349600
>> Mn 0.6666666865 0.3333333433 0.1666651666
>> Mn 0.6666666865 0.8333333134 0.1666651666
>> Mn 0.1666666418 0.8333333134 0.1666651666
>> Mn 0.1666666716 0.3333333433 0.1666651666
>> O 0.0000045120 0.2862591147 0.2499982566
>> O 0.7862546444 0.9999954701 0.2499982566
>> O 0.5000045299 0.2862591147 0.2499982566
>> O 0.7137408852 0.7137453557 0.2499982566
>> O 0.2137408704 0.7137453557 0.2499982566
>> O 0.0000045332 0.7862591148 0.2499982566
>> O 0.5000045300 0.7862591148 0.2499982566
>> O 0.7862546444 0.4999954998 0.2499982566
>> O 0.2137408704 0.2137453854 0.2499982566
>> O 0.2862546146 0.4999954998 0.2499982566
>> O 0.2862546146 0.9999954701 0.2499982566
>> O 0.7137408853 0.2137453854 0.2499982566
>> Sr 0.5000000000 0.5000000000 0.2500008941
>> La 0.5000000000 0.0000000000 0.2500008941
>> La 0.0000000000 0.0000000000 0.2500008941
>> La 0.0000000000 0.5000000000 0.2500008941
>> Mn 0.3333333432 0.1666666716 0.3333334625
>> Mn 0.8333333731 0.1666666716 0.3333334625
>> Mn 0.8333333731 0.6666666865 0.3333334625
>> Mn 0.3333333432 0.6666666865 0.3333334625
>> La 0.1666666716 0.3333333433 0.4166661203
>> Sr 0.6666666865 0.8333333134 0.4166661203
>> La 0.1666666418 0.8333333134 0.4166661203
>> La 0.6666666865 0.3333333433 0.4166661203
>> O 0.4529260695 0.6195876598 0.4166683852
>> O 0.9529260397 0.6195876598 0.4166683852
>> O 0.4529260695 0.1195876374 0.4166683852
>> O 0.1666615754 0.5470739603 0.4166683852
>> O 0.6666615605 0.5470739603 0.4166683852
>> O 0.9529260397 0.1195876374 0.4166683852
>> O 0.3804123402 0.8333383798 0.4166683852
>> O 0.1666615605 0.0470739342 0.4166683852
>> O 0.6666615605 0.0470739342 0.4166683852
>> O 0.8804123402 0.8333383798 0.4166683852
>> O 0.8804123402 0.3333384394 0.4166683852
>> O 0.3804123700 0.3333384394 0.4166683852
>> Mn 0.0000000000 0.5000000000 0.5000000000
>> Mn 0.5000000000 0.5000000000 0.5000000000
>> Mn 0.0000000000 0.0000000000 0.5000000000
>> Mn 0.5000000000 0.0000000000 0.5000000000
>> O 0.8333384394 0.9529260397 0.5833316446
>> O 0.3333384394 0.9529260397 0.5833316446
>> O 0.5470739603 0.8804123401 0.5833316446
>> O 0.6195876598 0.6666615605 0.5833316446
>> O 0.1195876300 0.6666615605 0.5833316446
>> O 0.0470739007 0.8804123401 0.5833316446
>> O 0.8333384395 0.4529260695 0.5833316446
>> O 0.3333384395 0.4529260695 0.5833316446
>> O 0.6195876598 0.1666615605 0.5833316446
>> O 0.0470739268 0.3804123700 0.5833316446
>> O 0.5470739604 0.3804123700 0.5833316446
>> O 0.1195876300 0.1666615605 0.5833316446
>> La 0.3333333432 0.1666666716 0.5833338499
>> La 0.8333333731 0.1666666716 0.5833338499
>> Sr 0.8333333731 0.6666666865 0.5833338499
>> La 0.3333333432 0.6666666865 0.5833338499
>> Mn 0.6666666865 0.3333333433 0.6666665674
>> Mn 0.1666666418 0.8333333134 0.6666665674
>> Mn 0.1666666716 0.3333333433 0.6666665674
>> Mn 0.6666666865 0.8333333134 0.6666665674
>> La 0.5000000000 0.0000000000 0.7499991060
>> La 0.0000000000 0.5000000000 0.7499991060
>> Sr 0.5000000000 0.5000000000 0.7499991060
>> La 0.0000000000 0.0000000000 0.7499991060
>> O 0.2137453854 0.0000045078 0.7500017285
>> O 0.2862591148 0.7862546444 0.7500017285
>> O 0.7862591148 0.7862546444 0.7500017285
>> O 0.7137454152 0.0000045078 0.7500017285
>> O 0.7862591147 0.2862546146 0.7500017285
>> O 0.9999954701 0.7137408853 0.7500017285
>> O 0.2862591147 0.2862546146 0.7500017285
>> O 0.9999954701 0.2137408853 0.7500017285
>> O 0.4999954701 0.2137408853 0.7500017285
>> O 0.4999954700 0.7137408853 0.7500017285
>> O 0.7137454152 0.5000045300 0.7500017285
>> O 0.2137454003 0.5000045300 0.7500017285
>> Mn 0.3333333432 0.6666666865 0.8333347440
>> Mn 0.8333333731 0.6666666865 0.8333347440
>> Mn 0.3333333432 0.1666666716 0.8333347440
>> Mn 0.8333333731 0.1666666716 0.8333347440
>> La 0.1666666716 0.3333333433 0.9166650772
>> La 0.6666666865 0.3333333433 0.9166650772
>> Sr 0.6666666865 0.8333333134 0.9166650772
>> La 0.1666666418 0.8333333134 0.9166650772
>> O 0.1666705460 0.1195919737 0.9166654348
>> O 0.6666705609 0.1195919737 0.9166654348
>> O 0.8804080486 0.5470785498 0.9166654348
>> O 0.1666705459 0.6195919513 0.9166654348
>> O 0.9529213905 0.8333294391 0.9166654348
>> O 0.4529214203 0.3333294690 0.9166654348
>> O 0.9529213906 0.3333294690 0.9166654348
>> O 0.4529214203 0.8333294391 0.9166654348
>> O 0.3804080188 0.0470785759 0.9166654348
>> O 0.8804080486 0.0470785759 0.9166654348
>> O 0.3804080189 0.5470785498 0.9166654348
>> O 0.6666705608 0.6195919513 0.9166654348
>>
>> K_POINTS {automatic}
>> 2 2 1 0 0 0
>>
>> HUBBARD (ortho-atomic)
>> U Mn-3d 4.0
>>
>>
>>
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