[QE-users] second step of scf in relax calculations didn't converge
Coralie Khabbaz
khabbaz.coralie at gmail.com
Wed Jul 1 19:25:20 CEST 2020
Hello Giuseppe,
where exactly should I include the switch?
Thank you!
------------------------------
*From:* users <users-bounces at lists.quantum-espresso.org> on behalf of
Giuseppe Mattioli <giuseppe.mattioli at ism.cnr.it>
*Sent:* Wednesday, July 1, 2020 12:36:14 PM
*To:* Quantum ESPRESSO users Forum <users at lists.quantum-espresso.org>
*Subject:* Re: [QE-users] second step of scf in relax calculations didn't
converge
A simpler but often effective trick: sometimes at (or after) the first
step your system may be trapped in an unlucky configuration that
prevent convergence of the scf iteration. You can either do as Matteo
says, or try (after inspecting the geometry of the second step to be
sure that your system isn't going bananas) to use the switch
scf_must_converge=.false.
Such switch forces the bfgs step even if the wfc is not fully
converged, and it is sensible only if your wfc is not very far from
convergence and in the initial steps of a 'relax' calculation. If you
are lucky, in a few steps you jump out of your "Bermuda triangle" and
further steps converge in a smoother way.
HTH
Giuseppe
Quoting Coralie Khabbaz <khabbaz.coralie at gmail.com>:
> Hello Matteo,
>
> Thank you so much for your reply. I didn't understand what do you mean by
> initial trust radius? Also, at first my convergence threshold was at 1^-6
> but the first scf step didn't converge in 1000 steps. Then, I fixed it at
> 1^-4 and the first step converged. So do you think I should tighten it? I
> didn't try starting a new scf from the new iconic positions because I
don't
> know how to.
>
> This is my input file:
>
> &CONTROL
> calculation = "relax"
> forc_conv_thr = 1.00000e-03
> max_seconds = 4.32000e+05
> nstep = 300
> pseudo_dir =
"/home/coralee/projects/def-jkopysci/coralee/.pseudopot"
> /
>
> &SYSTEM
> a = 8.32716e+00
> angle1(1) = 0.00000e+00
> angle1(2) = 0.00000e+00
> angle2(1) = 0.00000e+00
> angle2(2) = 0.00000e+00
> b = 8.98689e+00
> c = 2.52767e+01
> cosab = 6.12323e-17
> cosac = 6.12323e-17
> cosbc = -1.85547e-01
> degauss = 2.00000e-02
> ecutrho = 4.75221e+02
> ecutwfc = 5.03902e+01
> ibrav = 14
> nat = 48
> nbnd = 490
> nspin = 2
> ntyp = 2
> occupations = "smearing"
> smearing = "gaussian"
> starting_magnetization(1) = 2.00000e-01
> starting_magnetization(2) = 2.00000e-01
> /
>
> &ELECTRONS
> conv_thr = 1.00000e-04
> diagonalization = "david"
> electron_maxstep = 1000
> mixing_beta = 1.00000e-01
> mixing_mode = "local-TF"
> startingpot = "atomic"
> startingwfc = "atomic+random"
> /
>
> &IONS
> ion_dynamics = "bfgs"
> /
>
> &CELL
> /
>
> K_POINTS {automatic}
> 2 2 1 0 0 0
>
> ATOMIC_SPECIES
> N 14.00674 N.pbe-n-kjpaw_psl.1.0.0.UPF
> W 183.84000 W.pbe-spn-kjpaw_psl.1.0.0.UPF
>
> ATOMIC_POSITIONS {angstrom}
> N 3.207882 2.672960 14.837784
> N 7.371462 2.672960 14.837784
> N 3.207882 -1.820484 14.837784
> N 7.371462 -1.820484 14.837784
> W 3.207882 4.882815 14.748648
> W 7.371462 4.882815 14.748648
> W 3.207882 0.389371 14.748648
> W 7.371462 0.389371 14.748648
> N 1.126093 5.365612 14.468179
> N 5.289672 5.365612 14.468179
> N 1.126093 0.872168 14.468179
> N 5.289672 0.872168 14.468179
> W 1.126093 3.038143 14.415413
> W 5.289672 3.038143 14.415413
> W 1.126093 -1.455301 14.415413
> W 5.289672 -1.455301 14.415413
> N 3.207882 5.336567 12.630078
> N 7.371462 5.336567 12.630078
> N 3.207882 0.843123 12.630078
> N 7.371462 0.843123 12.630078
> W 3.207882 3.052977 12.540942
> W 7.371462 3.052977 12.540942
> W 3.207882 -1.440467 12.540942
> W 7.371462 -1.440467 12.540942
> N 1.126093 3.535775 12.260473
> N 5.289672 3.535775 12.260473
> N 1.126093 -0.957669 12.260473
> N 5.289672 -0.957669 12.260473
> W 1.126093 5.701750 12.207706
> W 5.289672 5.701750 12.207706
> W 1.126093 1.208305 12.207706
> W 5.289672 1.208305 12.207706
> N 3.207882 3.506729 10.422372 0 0 0
> N 7.371462 3.506729 10.422372 0 0 0
> N 3.207882 -0.986715 10.422372 0 0 0
> N 7.371462 -0.986715 10.422372 0 0 0
> W 3.207882 5.716584 10.333236 0 0 0
> W 7.371462 5.716584 10.333236 0 0 0
> W 3.207882 1.223140 10.333236 0 0 0
> W 7.371462 1.223140 10.333236 0 0 0
> N 1.126093 6.199382 10.052766 0 0 0
> N 5.289672 6.199382 10.052766 0 0 0
> N 1.126093 1.705938 10.052766 0 0 0
> N 5.289672 1.705938 10.052766 0 0 0
> W 1.126093 3.871912 10.000000 0 0 0
> W 5.289672 3.871912 10.000000 0 0 0
> W 1.126093 -0.621532 10.000000 0 0 0
> W 5.289672 -0.621532 10.000000 0 0 0
>
> On Wed, 1 Jul 2020 at 10:48, Matteo Cococcioni <matteo.cococcioni at unipv.it
>
> wrote:
>
>> Hello,
>>
>> it's very difficult to guess what is wrong in your input if you don't
show
>> it.
>> In any case, if you have converged forces and stresses on cut-off(s) and
>> number of k-points/smearing, it might be a good idea to tighten your
>> convergence threshold and reduce the initial trust radius. Maybe your
>> forces and stresses are so loosely converged and your ionic/cell step so
>> big that the system moves to a configuration that is difficult to
converge.
>> Or maybe your starting lattice parameter/ionic configuration are very far
>> from equilibrium and the system tries to make a big jump at the
beginning.
>> Also, have you tried to start a new scf from the new ionic position?
>>
>> Please add your affiliation
>>
>> Regards,
>>
>> Matteo
>>
>> Il giorno mer 1 lug 2020 alle ore 13:45 Coralie Khabbaz <
>> khabbaz.coralie at gmail.com> ha scritto:
>>
>>> Hello,
>>>
>>> I am doing a relax calculation on my WN (48 atoms) slab. The first step
>>> of scf calculations converged but then the second step didn't converge
in
>>> 1000 steps (which was my limit). So, the calculations stopped, and I got
>>> many files (data-file.xml, charge-density.dat, paw.txt,
>>> spin-polarization.dat...) but no output file. If my first scf step
>>> converged doesn't that mean that all of my other scf steps should
converge
>>> but need more steps? Or is there a problem in my input file?
>>> _______________________________________________
>>> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso
)
>>> users mailing list users at lists.quantum-espresso.org
>>> https://lists.quantum-espresso.org/mailman/listinfo/users
>>
>>
>>
>> --
>> Matteo Cococcioni
>> Department of Physics
>> University of Pavia
>> Via Bassi 6, I-27100 Pavia, Italy
>> tel +39-0382-987485
>> e-mail matteo.cococcioni at unipv.it <lucio.andreani at unipv.it>
>> _______________________________________________
>> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso)
>> users mailing list users at lists.quantum-espresso.org
>> https://lists.quantum-espresso.org/mailman/listinfo/users
GIUSEPPE MATTIOLI
CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
Via Salaria Km 29,300 - C.P. 10
I-00015 - Monterotondo Scalo (RM)
Mob (*preferred*) +39 373 7305625
Tel + 39 06 90672342 - Fax +39 06 90672316
E-mail: <giuseppe.mattioli at ism.cnr.it>
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