[gpaw-users] Convergence using GLLBSC

[Marcin Dulak]

Hi,

On 07/14/2014 08:02 AM, Hongliang Xin wrote:
> Dear All,
>
> I am testing a small Ag cluster with 56 atoms using GLLBSC for better 
> description of electronic structure. The convergence is really bad. I 
> am just wondering anyone has some tips for using GLLBSC functional in 
> general. I paste here the calculator and convergence.
please provide a full script.
Which version of GPAW and setups are you using?
>
> Thanks,
> Hongliang
>
> Here is calculator:
> calc = GPAW(mode = 'fd',
>             basis = 'dzp',
>             nbands = -int(len(atoms)*5*0.15),
>             xc = 'GLLBSC',
>             kpts = (1,1,1),
>             #poissonsolver=PoissonSolver(relax='GS', eps=1e-10, nn='M'),
>             occupations=FermiDirac(0.01),
>             convergence={#'energy': 1.0e-3,
>                          #'density': 1.0e-4,
>                          #'eigenstates': 1.0e-8,
>                          'bands': -30},
if you are converging unoccupied bands then you need eigensolver=Davidson(N)
or eigensolver=CG(N), with N being ~3. Davidson is few times faster but 
may perform more steps.
Do not decrease convergence thresholds, and start with defaults
(i have put a # mark for things to be commented out).

Best regards,

Marcin
> #mixer=Mixer(beta=0.005,nmaxold=7,weight=50.0),
>             spinpol = False,
>             usesymm = False,
>             maxiter = 1000,
>             gpts=h2gpts(0.18, atoms.get_cell(), idiv=8),
>             txt='out.txt',
>             verbose=False)
>
> Here is the convergence:
> iter: 988  19:29:53  -2.9   -2.3     -133.856014  2 5
> iter: 989  19:30:22  -2.7   -2.2     -133.543733  3 8
> iter: 990  19:30:50  -3.1   -2.6     -133.450748  2 3
> iter: 991  19:31:17  -3.3   -2.7     -133.489621  3 2
> iter: 992  19:31:46  -3.2   -2.5     -133.613931  3 4
> iter: 993  19:32:14  -3.2   -2.4     -133.650107  3 4
> iter: 994  19:32:42  -3.2   -2.3     -133.608913  2 4
> iter: 995  19:33:12  -3.4   -2.3     -133.687230  3 5
> iter: 996  19:33:40  -3.7   -2.2     -133.720904  2 3
> iter: 997  19:34:08  -3.4   -2.2     -133.658227  3 5
> iter: 998  19:34:37  -3.4   -2.3     -133.594052  2 5
> iter: 999  19:35:07  -3.1   -2.3     -133.577819  3 5
> iter: 1000  19:35:36  -3.1   -2.4     -133.606794  3      5
>
>
> -- 
> Hongliang Xin
> Postdoc
> SUNCAT
> SLAC National Accelerator Laboratory
> Stanford University
> Phone: (734) 474-3629
> E-mail: hxin at slac.stanford.edu <mailto:hxin at umich.edu>
> hongliang06 at gmail.com <mailto:hongliang06 at gmail.com>
>
>
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