[Wannier] parameter to control convergence

[Jonathan Yates]

On Fri, 1 Sep 2006, Tadashi Ogitsu wrote:

> Smaller Im/Re ratio is better, right? Generally speaking, how small one 
> should expect?

  Yes. In all the systems I've looked at it has been possible to find MLWF 
with a Im/Re ratio < 0.001. However, my experience is with relatively 
small systems (<40WF).
  With the disentanglement procedure it is possible to find WF that are 
localised, but not real. I generally take this as an indication that I 
should extract a different number of WF, or change the energy windows.

> I've checked the routine. It calculate the phase at the position that the 
> MLWF's amplitude gets max, and subtract the phase from the MLWF at each grid 
> point. Then, calculate absolute value of Im/Re ratio where the MLWF's 
> amplitude get large than 0.01, and printout the maximum number for each MLWF. 
> Do I understand correctly?

  You do.


  Thanks for pointing out the bug in the plotting routine when the number 
of atoms is >100. Tone is right, just replace the ** with 105.

  I should add that the xsf file you sent has another problem which may 
prevent it from working; namely the file contains uninitialised data - it's 
not clear to me how this happened. But I'll contact you directly about it.

  Yours
   Jonathan


-- 
Dr Jonathan Yates:  email: jryates at lbl.gov   phone: 510-642-7302
Material Science Division, Lawrence Berkeley National Laboratory  and
Department of Physics, University of California,
366 Le Conte Hall #7300, Berkeley, CA 94720-7300, USA