[Q-e-developers] Trouble with vc-relax: "Too many g vector" error

[Paolo Giannozzi]

Please try the following: change line 101 of FFTXlib/stick_base.f90 to
   ELSE IF( smap%nstx < nstx .OR. smap%ub(3) /= ub(3) ) THEN
Does this fix your problem?

Paolo

On Thu, Mar 23, 2017 at 5:15 PM, Mohammadreza Karamad
<karamadr at gmail.com> wrote:
> Hi,
>
> I am attempting to optimize
> a
> unit cell for a H2MnO4 compound using vc-relax in ase-espresso. I have got
> the following strange error:
> "too many g-vectors"
> I have used a e-cut of 45 Ry
>  which basically should be high enough
> .
> I have also tried with different e-cut values, both smaller and bigger. For
> the former ones, I get the error of "g-vectors missing"
> . Although I am not sure,
> I think this error has some thing to do with the e-cut.
>
> During cell relaxation, it seems that the size of the cell changes
> significantly by ~10 Angstrom^3.
>  Moreover, it seems that the I got this error in the last step just before
> performing scf calculations on the optimized structure, where the
> calculations fail.
>
>  I have taken a cell_factor of 5,much larger than the default value,
> i.e.,1.2. Below you can find the details of the calculators as well as
> different parameters for vc-relax calculations. I would like to say that I
> have used ase-espresso.
>
>     calculator = espresso(pw=600,
>         dw=6000,
>         xc='PBE',
>         kpts = (6,6,6),
>         nbands=-10,
>         mode='vc-relax',
>         cell_dynamics='bfgs',
>         opt_algorithm='bfgs',
>         cell_factor=5,
>         spinpol=spinpol,
>         outdir= outdir)
>
> Any help will be appreciated,
>
> Best,
>
> Reza
>
>
>
>
>
>
>
>
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-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222