[Ifeffit] is there any ongoing effort to integrate feff and larch?

Matt Newville newville at cars.uchicago.edu
Sat Jan 3 12:13:16 CST 2015

Hi Angel,

On Tue, Dec 30, 2014 at 10:46 PM, Angel Yanguas-Gil <angel.yanguas at gmail.com
> wrote:

> So far it seems from the sphinx doc that feff cannot be called from
> larch. Is there any ongoing effort to implement that? The simplest way
> would be to create a python module to generate the corresponding
> feff.inp file, but I'd hate to duplicate someone else's work.
> Thanks!
> Angel
> _______________________________________________
> Ifeffit mailing list
> Ifeffit at millenia.cars.aps.anl.gov
> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit

Happy New Year.

You are right that there is currently not a simple mechanism for calling
feff from larch.  Of course, on could make a system call, but that's not
specifically about using feff.  It should be fairly straightforward to
write a function (or class) to generate a feff.inp file and call the feff
executable.  As far as I know, no one has done this.  If you're interested,
that would be a great addition!  I'd be happy to help anyway I can.

My expectation had been that most people would be using larch from Artemis,
but that hasn't happened, yet.  I have been focusing much of my efforts in
the past year or so on beamline and microprobe software, and less on EXAFS
analysis.  But, improving the interaction with Feff is an important need
for larch, and would be really useful.

We have sort of "Grand Plans" for this, using the recently released
Feff8.5-for-EXAFS (see http://github.com/xraypy/feff85exafs) to make a more
interactive, and callable version of Feff, so that one might create a set
of Potentials, then build scattering paths (and calculate the EXAFS for
them) dynamically.  Bruce has been working on this quite a bit over the
past several months.  For this, the eventual plan is to get rid of much of
the "Control Card" aspect of feff.inp, and instead make functions (for
C/Fortran/Perl/Python/larch) to do things like
    CalculatePotentials(list_of_atoms, ...)

    GenerateEXAFS(potenials_data, scattering_path)

I don't think we have a definite time-line for that, and it is probably
many months away.  But, I think that an effort to generate and call Feff6
or Feff8 would be great, and could easily be modified / extended to use
this next generation of Feff-for-EXAFS.

Neither Bruce nor I do this development full-time, and we'd love help on
any aspect of this work.


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