[Wannier] seek help

[Nicola Marzari]

Dear Hongwei,

guiding centers were used to suggest how to properly choose the branch
cut in the evaluation of complex logarithms - the logic is explained 
inside wann_phases
(basically making sure that roughly every contribution that you add up 
in evaluating
the position of the wannier center has a branch cut that is closest to 
giving that position),
but these days you'd be better off by choosing carefully your 
projections, and forgetting
about the guiding cetners (keywords are nevertheless explained in the 
user guide).

With regard to conv_noise... , it must be something Arash or Jonathan 
coded? Looks like
a way to get unstuck from very shallow minimizations (e.g. as in the 
rotation of the d-orbitals
in a system where localization is almost invariant with respect to 
rotation).

nicola


On 3/14/11 4:12 PM, Hongwei Wang wrote:
> Dear Wannier90 users
>   I am a Ph. D student in the Key Laboratory of Quantum Information, University of Science and Technology of China. I am beginner in using the Wannier90 code, I can't well understand the Key word "guiding_centres". I wonder if you can tell me its physical picture and the situation in which we should use guiding_centres? In addition, I want to know how to set the Key word num_guide_cycles£¬num_no_guide_iter£¬ conv_noise_amp£¬  conv_noise_num  reasonablely.
> can you tell me some experience to set them.
>   Thanks for any of your help£¡
>
> Sincerely,
> Hongwei Wang
>
>
>
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> Wannier at quantum-espresso.org
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Prof Nicola Marzari   Department of Materials Science and Engineering
13-5066   MIT   77 Massachusetts Avenue   Cambridge MA 02139-4307 USA
tel 617.4522758 fax 2586534 marzari at mit.edu http://quasiamore.mit.edu