[QE-users] second step of scf in relax calculations didn't converge

Giuseppe Mattioli giuseppe.mattioli at ism.cnr.it
Wed Jul 1 20:02:26 CEST 2020


Into the &electrons namelist
Best
G.

Quoting Coralie Khabbaz <khabbaz.coralie at gmail.com>:

> 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>
>
> _______________________________________________
> 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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