[Pw_forum] wavefunction coefficients

[lshulenburger at ciw.edu]

The pw2casino utility may be of use for this case.  Run as a
postprocessing step after a scf or nscf calculation, it writes a plaintext
file which first lists the G vectors in order, then for each k-point the
coefficients of those G vectors for each band.  It's output is rather
verbose, but it is reasonably self documenting so it might be worth a
look.  As for hdf output, I know the group developing the qmcpack code at
the University of Illinois does exactly this, but for the moment they use
pw2casino as an intermediate step and I'm not sure whether the code is
released.  Hope this helps.

Luke Shulenburger
Geophysical Laboratory
Carnegie Institute of Washington


>
> Thank you Gabriele! Since most of the time the *.wfc* are split among a
> few files, a utility that uses as input only the number of processors,
> nspin, and perhaps the number of basis functions could be useful. If the
> wfc files would be in hdf5 format it would be probably easier to figure
> out all their structure, but since this is not the case, a utility program
> could be quite useful for this purpose.
>
> Karoly
>
> ***********************************************************************
> Karoly Nemeth, Ph.D.
> Argonne National Laboratory
> 9700 S. Cass Ave. Argonne, IL 60439.
> Advanced Photon Source
> Accelerator Physics and Operations Group
> Building 401, Room B2200
> Tel. 630-252-5813
> Fax: 630-252-4732
> ***********************************************************************
>
>
>
>> Message: 3
>> Date: Thu, 22 Jan 2009 09:54:17 +0100
>> From: Gabriele Sclauzero <sclauzer at sissa.it>
>> Subject: Re: [Pw_forum] wavefunction coefficients
>> To: PWSCF Forum <pw_forum at pwscf.org>
>> Message-ID: <49783439.40104 at sissa.it>
>> Content-Type: text/plain; charset=us-ascii; format=flowed
>>
>> 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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