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

[Ivan Rungger]

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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