[Pw_forum] too many g-vectors

[Ari P Seitsonen]

Dear Amir,

   First of all, I can give only very general answer. One point is that you 
are using the HGH pseudo potentials: I think that for oxygen you probably 
have to go to cut-off energies exceeding 100 Ry to get reasonable energies 
and forces, and the stress would probably need more; I do not know if Na 
would need even more, if it has the semi-core electrons in the valence. 
Have you tested that you have at least some kind of convergence in the 
values of the pressure?

   Getting these kind of errors as you receive might mean that the cell 
changes too much from the initial cell; did you check for how big the 
stresses are in the initial geometry, even after the calculation 'relax' 
(in case you printed out the stress tensor)? If those are veryveryvery 
large, you could try to relax the cell first "by hand", along the large 
components of the stress tensor. I do not know if increasing the value of 
the variable 'cell_factor' from the default 1.2 could help. I would start 
by increasing the cut-off energy (no need to specify 'ecutrho') and 
studying the stress tensor.

     Greetings from Sunny Paris,

        apsi

-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
   Ari Paavo Seitsonen / Ari.P.Seitsonen at iki.fi / http://www.iki.fi/~apsi/
     Ecole Normale Supérieure (ENS), Département de Chimie, Paris
     Mobile (F) : +33 789 37 24 25    (CH) : +41 79 71 90 935


On Tue, 26 Apr 2016, Mofrad, Amir Mehdi (MU-Student) wrote:

> 
> Dear all QE users and developers,
> 
> 
> I want to do a cell optimization (vc-relax) but I keep getting the following error:
> 
>  task #         0
>      from ggen : error #       150
>      g-vectors missing !
> I also have tried changing the ecutwfc as well yet, It gives me the same error. When I look at the output file it seems that
> it has finished the optimization but it's not able to run the last SCF step using the final coordinates. Also when I visualize
> it in Xcrysden, the structure distorts significantly which may not be reasonable.
> 
> 
> Here is my input file in case you might need to take a look at. Any help would be thoroughly appreciated.
> 
>  &CONTROL
>                  calculation = 'vc-relax' ,
>                 restart_mode = 'from_scratch' ,
>                   wf_collect = .true. ,
>                       outdir = './scratch' ,
>                       wfcdir = './scratch' ,
>                   pseudo_dir = '/global/espresso/pseudo' ,
>                       prefix = 'SOD' ,
>                    verbosity = 'high' ,
>                etot_conv_thr = 1e-5 ,
>                forc_conv_thr = 1e-4 ,
>                        nstep = 50 ,
>                      tstress = .true. ,
>                      tprnfor = .true. ,
>  /
>  &SYSTEM
>                        ibrav = 0,
>                          nat = 41,
>                         ntyp = 4,
>                      ecutwfc = 60 ,
>                      ecutrho = 240 ,
>  /
>  &ELECTRONS
>             electron_maxstep = 100,
>                     conv_thr = 3e-8 ,
>                  mixing_mode = 'plain' ,
>                  mixing_beta = 0.2 ,
>              diagonalization = 'david' ,
>  /
>  &IONS
>                 ion_dynamics = 'bfgs' ,
>             trust_radius_ini = 0.5 ,
> /
> &CELL
>         cell_dynamics='bfgs',
>         cell_factor=6,
>  /
> CELL_PARAMETERS angstrom
>      9.000    0.000    0.000
>      0.000    9.000    0.000
>      0.000    0.000    9.000
> ATOMIC_SPECIES
>    Si   28.08600  Si.pz-hgh.UPF
>     O   15.99940  O.pz-hgh.UPF
>     Al  26.981539 Al.pz-hgh.UPF
>     Na  22.989769 Na.pz-hgh.UPF
> ATOMIC_POSITIONS angstrom
> Si   2.21200   0.00000   4.42400
> Si   6.63600   0.00000   4.42400
> Si   4.42400   2.21200   0.00000
> Si   4.42400   6.63600   0.00000
> Si   0.00000   4.42400   2.21200
> Si   0.00000   4.42400   6.63600
> Si   2.21200   4.42400   0.00000
> Al   6.63600   4.42400   0.00000
> Al   0.00000   2.21200   4.42400
> Al   0.00000   6.63600   4.42400
> Al   4.42400   0.00000   2.21200
> Al   4.42400   0.00000   6.63600
> O   1.20864   3.83826   1.31835
> O   7.63936   5.00974   1.31835
> O   7.63936   3.83826   7.52965
> O   1.20864   5.00974   7.52965
> O   1.31835   1.20864   3.83826
> O   1.31835   7.63936   5.00974
> O   7.52965   7.63936   3.83826
> O   7.52965   1.20864   5.00974
> O   3.83826   1.31835   1.20864
> O   5.00974   1.31835   7.63936
> O   3.83826   7.52965   7.63936
> O   5.00974   7.52965   1.20864
> O   8.26226   5.63264   5.74235
> O   0.58574   3.21536   5.74235
> O   8.26226   3.21536   3.10565
> O   0.58574   5.63264   3.10565
> O   5.63264   5.74235   8.26226
> O   3.21536   5.74235   0.58574
> O   3.21536   3.10565   8.26226
> O   5.63264   3.10565   0.58574
> O   5.74235   8.26226   5.63264
> O   5.74235   0.58574   3.21536
> O   3.10565   8.26226   3.21536
> O   3.10565   0.58574   5.63264
> Na   7.51726   1.33074   7.51726
> Na   1.33074   7.51726   7.51726
> Na   5.75474   5.75474   5.75474
> Na   5.75474   3.09326   3.09326
> Na   3.09326   5.75474   3.09326
> 
> K_POINTS automatic
>   2 2 2   1 1 1
> 
> 
> P.S. When I do the same simulation with relax instead of vc-relax it runs well without any error. However, my task is to do
> cell optimization (vc-relax) rather than geometry optimization (relax) .
> 
> 
> 
> Best,
> 
> 
> 
> Amir M. Mofrad   
> 
> University of Missouri
> 
> 
>