[Ifeffit] FEFF report: Hard tests failed in fovrg.
kevinjorissenpdx at gmail.com
Wed Aug 7 13:29:05 CDT 2013
Dear Ifeffit community,
a short reaction from the FEFFgroup.
1/ It's true that we don't follow up on the ifeffit ML 100%. Important
issues usually do get through to us. We highly value the ifeffit
community. We can also be contacted directly for problems that are FEFF
related rather than iFEFFit related (
We'll likely ask you for the feff.inp file that generates the problem.
2/ We're glad that FEFF6 is so successful. Meanwhile FEFF6 is about as
old as Windows95, and development is now focused on
which has 15-20 years of improvements over FEFF6. It's a big improvement
for anyone running FEFF calculations. It costs $500, or $250 upgrade from
any paid version of FEFF.
3/ The OP posted 5 input files. 4 of these run without problems in FEFF9.
The last has I atoms (Z=53) at a spacing of 0.8A, and doesn't run out of
the box. I expect the same result from FEFF8.
4/ There has been some effort to bring a "FEFF9lite" to the analysis
codes, analogous to the FEFF6lite discussed here. We would be very happy
to see that effort succeed.
5/ FWIW the fovrg routine was retired in 1996 and replaced by a
relativistic version called "dfovrg". The "hard error" does not exist
6/ We're a small team; we apologize for all the 'bothering' we don't get
around to. We do care about supporting our users and put a lot of energy
into support. Please reach out ot us when you need us.
Cheers from Seattle,
PS I posted a while back about a problem with JFEFF and Java updates but
I'm not sure the message made it through: I asked the mod, but no reply. I
hope this msg makes it :).
On Wed, Aug 7, 2013 at 8:24 AM, Bruce Ravel <bravel at bnl.gov> wrote:
> On 08/06/2013 11:55 AM, Naumova, Maria wrote:
>> May I use this FEFF calculation as a valid base for future fit? Or
>> this error means that FEFF doesn't work correct and I can't rely on
>> its output? If the phase-shift program failed to converge does it
>> mean that it could stop in some completely unrealistic result?
> You are correct that the version of Feff6 that we are allowed to give
> away for free reliably complains about failing something called a
> "hard test". This is some kind of convergence test on the computation
> of the muffin tin potential.
> The test is made in the lines just prior to this:
> The error is reported here:
> If you can make heads to tails out of the calculation in fovrg.f, you
> are vastly smarter than me, vastly more patient than me, or both!
> I have 2 comments on the main point of your post:
> 1. As you noted, this question has been asked many times before. Not
> once has anyone from the Feff project (i.e. anyone who might
> actually have a working knowledge of that bit of code) bothered to
> comment. It would be lovely to hear from one of them.
> 2. This very version of Feff has been included with Ifeffit and with
> the packages I build for my software for years. Over a decade, in
> fact. In that time, Feff, Ifeffit, and my software have been used
> for defensible data analysis thousands of times and by hundreds of
> That does not mean that any part of the software stack is actually
> correct. But it does mean that lots of article writers and lots
> of article reviewers have accepted the results coming from this
> stack of software.
> That does not mean that you should accept it. Quite the contrary
> -- you would be wise to question every part of the software stack.
> You may even find that you will need to discard any or all parts
> of that software stack and replace them with something you trust
> more -- perhaps even with something that you, yourself have
> To summarize, I am saying the same thing I have said in the past. I
> don't understand the code that generates that message. No one from
> the Feff project has ever bothered weighing in on what it means. No
> one has demonstrated that it represents an actionable problem. The
> codes which use Feff have been in use for years to produce defensible
> So, in conclusion, what should you do? I have no idea. My advice is
> to continue using the software, but my advice may not be any more
> reliable than the software itself.
> I hope that helps. Probably doesn't, but it's the best I can do.
> Bruce Ravel ------------------------------**------ bravel at bnl.gov
> National Institute of Standards and Technology
> Synchrotron Science Group at NSLS --- Beamlines U7A, X24A, X23A2
> Building 535A
> Upton NY, 11973
> Homepage: http://xafs.org/BruceRavel
> Software: https://github.com/bruceravel
> Ifeffit mailing list
> Ifeffit at millenia.cars.aps.anl.**gov <Ifeffit at millenia.cars.aps.anl.gov>
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