[gpaw-users] Re: Convergence error

[Vincent Davesne]

Jens Jørgen Mortensen wrote:
> On Mon, 2010-04-19 at 13:38 +0200, Vincent Davesne wrote:
>   
>> Hi!
>>
>> Ask Hjorth Larsen wrote:
>>     
>>> Hi Vincent
>>>
>>> On Fri, 16 Apr 2010, Vincent Davesne wrote:
>>>
>>>       
>>>> Hi!
>>>>
>>>> I have a problem with the code I used.
>>>>
>>>> from ase import *
>>>> from ase.lattice.surface import *
>>>> from gpaw import GPAW
>>>>
>>>> slab = fcc111('Ag', size=(3,3,3), vacuum=5.0)
>>>>
>>>> calc = GPAW(mode='lcao',basis='dzp',h=0.2,nbands=-10,xc='RPBE', 
>>>> txt='Ag111.out')
>>>>
>>>> slab.set_calculator(calc)
>>>>
>>>> constraint = FixAtoms(mask=[a.get_tag() != 1 for a in slab])
>>>> slab.set_constraint(constraint)
>>>>
>>>> dyn = QuasiNewton(slab, trajectory='Ag111_f.traj')
>>>> dyn.run(fmax=0.05)
>>>>
>>>> gives back:
>>>> gpaw.KohnShamConvergenceError: Did not converge!
>>>>
>>>> It's just a relaxation of an Ag fcc 111 terrace surface. How can I 
>>>> solve this issue?
>>>> Thanks a lot,
>>>> Vincent
>>>>         
>>> Increasing the electronic temperature probably works.  Also, you could 
>>> try changing the mixer or adding some k-points.  Does the basis you 
>>> are using correspond to RPBE?  Attaching the calculation log is 
>>> generally a good idea.
>>>       
>> I tried to increase the electronic temperature, but
>> calc = GPAW(mode='lcao',basis='dzp',h=0.2,nbands=-10,xc='RPBE', 
>> txt='Ag111_2.out', occupations=FermiDirac(0.1))
>>
>> gives back immediately
>> NameError: name 'FermiDirac' is not defined
>>
>> So I tried to increase the number of k points, by specifying
>> calc = GPAW(mode='lcao',basis='dzp',h=0.2,nbands=-10,xc='RPBE', 
>> txt='Ag111_2.out',kpts=(4,4,1))
>>     
>
> Looks like more k-points works quite well.  I would also use more than
> 10 empty bands - this can also improve convergence.
>
>   
>> gives back after the run
>> NotImplementedError
>>     
>
> For version 0.6, forces are not implemented for non-orthogonal unit
> cells.  You have to use the development version of GPAW to get forces.
> Sorry :-(
>
> JJ
>
>   
Hi,

You mean that I can't get a proper calculation with this version of 
gpaw? Aaaaw...

Best Regards,
Vincent