[Smeagol-discuss] What's wrong with the Pulay mixing?

[Xiaohong Zheng]

Hello, Dear Ivan,

With this patch, the oscillations are gone and it works very well now.
Thank you so much for your nice work.

Sincerely,
Xiaohong




Ivan Rungger wrote:
> Hello Xiaohong,
>
> here is a patch for the pulayx.F file that should remove the
> oscillations in the convergence. You can copy the file into the Src
> directory and then run "patch pulayx.F pulay_mixing.patch".
> Alternatively you can also read the patch file and just change the few
> lines by hand in pulayx.F.
>
> Cheers,
>
> Ivan
>
> Xiaohong Zheng wrote:
>   
>> Hello, Dear All,
>>
>> Pulay mixing is a convergency accelerator. However, in a very simple
>> test, it was found that it slowed down the convergence. The
>> "DM.NumberPulay" was set to 5 and "DM.MixingWeight" is set to 0.1. In
>> the scf process, we can see that for every 5 steps, "dDmax" does not get
>> better, but gets worse. It is oscilating!
>>
>> However, if I set "DM.NumberPulay 5" and "DM.MixingWeight 0.2" or just
>> set "DM.NumberPulay 1", then it works very well and converges with 5 or
>> 6 steps. Thus, I think there must be some problem with the Pulay mixing.
>> Does anybody know why?
>>
>> The input and output files and the pseudopotential file is attached.
>> Thank you very much.
>>
>> Xiaohong
>>   
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>
>