[QE-users] sternheimer_kernel: root not converged in phonon calculations

[Lorenzo Paulatto]

Bonjour Pascal,

on which representation of which q-point does this happen?

The first rep of q-point 2 seems to converge perfectly fine on my PC.

I'd try to reproduce, but I would rather avoid repeating all the points.

cheers

On 27/08/2022 17:57, pboulet wrote:
> Dear all,
>
> I am encountering the problem mentioned in the subject of this post.
>
> Do you know to solve this problem?
>
> I am running ph.x on Mg2Si (not a big deal!) with NC pseudopotentials 
> from dojo website.
> I have optimized the structure, then ran a SCF with 60 k-points.
>
> Here is the input for ph.x:
> Mg2Si Phonon
> &inputph
>   verbosity   = 'high',
>   alpha_mix(1)= 0.1,
>   tr2_ph      = 1.0d-12,
>   diagonalization = 'cg',
>   prefix      = 'Mg2Si',
>   ldisp       = .true.,
>   epsil       = .true.,
>   lqdir       = .true.,
>   search_sym  = .false.
>   fildyn      = 'Mg2Si.dyn.xml',
>   fildvscf    = 'dvscf'
>   recover     = .true.,
>   start_q = 2, last_q = 8,
>   nq1=4, nq2=4, nq3=4,
> /
>
> and a sample of the output:
> iter #  41 total cpu time :  5901.1 secs av.it <http://av.it>.: 210.4
>       thresh= 1.000E-02 alpha_mix =  0.100 |ddv_scf|^2 =  1.350+100
>      kpoint   3 sternheimer_kernel: root not converged, thresh < 
>  3.699E+06
>      kpoint   4 sternheimer_kernel: root not converged, thresh < 
>  2.570E+03
>      kpoint   5 sternheimer_kernel: root not converged, thresh < 
>  1.322E+43
>      kpoint   6 sternheimer_kernel: root not converged, thresh < 
>  4.836E+01
>      kpoint   7 sternheimer_kernel: root not converged, thresh < 
>  2.110E-01
>      kpoint  12 sternheimer_kernel: root not converged, thresh < 
>  2.237E+25
>      kpoint  13 sternheimer_kernel: root not converged, thresh < 
>  1.420E+01
>      kpoint  14 sternheimer_kernel: root not converged, thresh < 
>  1.199E+21
>      kpoint  15 sternheimer_kernel: root not converged, thresh < 
>  6.741E+07
>      kpoint  18 sternheimer_kernel: root not converged, thresh < 
>  8.917E+00
>
> Note that the calculation ran fine for the Gamma point, so in the 
> present run I ‘recovered’ for k-points 2 to 8.
>
> The input file for the SCF calculation is:
> &CONTROL
>   title          = 'Mg2Si',
>   calculation    = 'scf',
>   etot_conv_thr  = 1d-9,
>   tprnfor        = .true.,
>   tstress        = .true.,
>   restart_mode   = 'restart',
>   verbosity      = 'high',
>   prefix         = 'Mg2Si',
>   wf_collect     = .true.,
> /
> &SYSTEM
>   ibrav          = 2,
>   celldm(1)      = 12.037d0,
>   nat            = 3,
>   ntyp           = 2,
>   ecutwfc        = 100.d0,
>   ecutrho        = 400.d0,
>   occupations    = 'fixed',
>   nbnd           = 20,
> /
> &ELECTRONS
>   conv_thr       = 1d-12,
>   mixing_beta    = 0.2d0,
> /
> ATOMIC_SPECIES
> Mg 24.3 Mg.upf
> Si 28.1 Si.upf
>
> ATOMIC_POSITIONS crystal
> Si       0.000000000   0.000000000   0.000000000
> Mg       0.250000000   0.250000000   0.250000000
> Mg       0.750000000   0.750000000   0.750000000
>
> K_POINTS automatic
> 8 8 8 1 1 1
>
> Thank you for your help and time.
> Best regards,
> Pascal
>
> .
> Pascal Boulet
> —
> /Professor in computational materials chemistry - DEPARTMENT OF CHEMISTRY/
> University of Aix-Marseille - Avenue Escadrille Normandie Niemen - 
> F-13013 Marseille - FRANCE
> Tél: +33(0)4 13 55 18 10 - Fax : +33(0)4 13 55 18 50
> Email : pascal.boulet at univ-amu.fr
>
>
>
>
>
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-- 
Dr. Lorenzo Paulatto
IdR @ IMPMC - CNRS UMR 7590 & Sorbonne Université
phone: +33 (0)1 442 79822 / skype: paulatz
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