[Pw_forum] wavefunction coefficients

[Gabriele Sclauzero]

Hi,

    of course Paolo and Axel could help you much more than me on this issue, but inthe 
meanwhile:

Karoly Nemeth wrote:
> Hi,
> 
> I would like to obtain the wavefunction coefficients u(i,k,G), where "i" 
> is the band-index, "k" is the k-space vector used in the discretization of 
> the Brillouin-zone in a PW calculation and "G" is the plane-wave basis
> function's wave-vector (assuming a complex form as exp[i(k+G)r] ).

I think that the quantities you are interested in are store in the variable "evc" of the 
pw program (but only in certains parts of the program and only for one k-point at a time; 
  the wavefunctions for all the k-points are stored on the .wfc files).

> 
> Is there any utility program that is independent from the rest of PWSCF 
> and would provide some sort of tabulation on u(i,k,G) as a function 
> of i,k and G , for a parallel calculation? Perhaps a quick quide to the 
> format of this information in the *.wfc* files written by a parallel run?

Be careful that in parallel runs the G vectors (i.e. plane waves) are split across 
processor, so that each processor may be working only with a slab of the full grid.
The option wfc_collect=.TRUE. collects all wavefunctions on a single file after the 
parallel run (maybe it can help you understand how to gather all the coefficients).

GS

PS: The forum community would be grateful if you specify your affiliation... thanks.

> 
> I would appreciate any hint that could save me some time from going 
> through the source code for this info.
> Thanks a lot in advance:
> 
> Karoly
> 
> 
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