[Ifeffit] Possible bug in atoms files generation by Artemis

[Matt Newville]

Hi Matthew,

On Thu, Mar 28, 2013 at 11:04 AM, Matthew Marcus <mamarcus at lbl.gov> wrote:
> Many years back, when FEFF stopped being free, I was told that the decision
> was not Rehr's but forced by the university.  Blame them.
> It's always easier and more pleasant for us to blame faceless university
> beauraucrats than scientists anyway :-)

Sure.  I'm not actually trying to assign blame.  The license exists,
and we accept it.  I'm just pointing out that the license and format
are out of our control, and that they have real impacts.  We've
encouraged changes to be made, and would be happy to help in any way
we can.  Complaining further isn't really constructive.

> I agree that FEFF input is broken.  This was, perhaps, inevitable as FEFF
> evolved over the years.  It may be (I haven't studied the matter)
> that the old format, which was perfectly good in its day, simply can't
> accommodate new features just by adding new keywords.  I really
> can't blame the Project very much for changing the format.  Still, the
> formats are documented, so I don't buy the idea that nothing can be
> done with FEFF8 until the Project changes its format or goes open-source.

Well, sure.  In fairness, Bruce has tried to support both "Feff6" and
"Feff8" files for many years.  But it's certainly forgivable to not
support all features of every version, especially when there is no
support code provided for reading the input files, and there is little
communication about changes made.  Again, this is not saying that we
refuse to support versions of Feff until it is released in a way we
prefer, it's saying that we can't support things we don't know how to
support.

> I can understand a reluctance to go open-source because they
> now keep tight control over portability and the embodied physics, such that
> everybody knows exactly what 'we used FEFF8.4' means.  If it
> went open-source, it may be imagined that there'd be a proliferation of
> versions, some of them with dubious hacks.

I'm not worried about dubious hacks myself, but that's one possible
rationale for not choosing an open source model.   At this time, the
number of scientists both interested in X-ray spectroscopy and fluent
in Fortran is rapidly diminishing, so there are very fee people would
able and willing to work on Feff.  The code I've seen is not all that
well commented.   I'm more concerned that no one will be able to
maintain Feff than I am that someone will break it.

> One fix I could imagine the Project doing is to release as open-source an input
> module for FEFF9, which is broken up into separate modules anyway.  That way,
> people could have whatever input format they wanted, but the integrity of FEFF
> would be preserved.

Maybe.  Bruce and I tried to pursue such a process many years ago.  We
begged them to make a library of modular routines that could be tied
together better, and to get rid of the damn control cards.  We tried,
we failed, we've given up and moved on.  We're not Feff developers,
and we don't have any special insight on new versions or any influence
on development.  Indeed, they've reinvented wheels (reading CIF files,
accessing remote servers) where they could have used Bruce's work and
chose not to do so.   When working on Bayesian analysis, they did not
consult with me until well after publishing, then sent a hacked
version of fefft  well after ifeffit was out, as if I should add it to
something.  It sits on my shelf still.   The Feff project very clearly
wants to not work with us.  Again, I don't mean to complain about
this, just trying to set the record straight.

--Matt