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 ( contact<http://www.feffproject.org/feffproject-contact.html> ). 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 FEFF9<http://www.feffproject.org/feffproject-feff.html>, 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 anymore. 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, Kevin Jorissen 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 <bra...@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? >> > > > Maria, > > 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: > > https://github.com/newville/**ifeffit/blob/master/src/feff6/**fovrg.f#L158<https://github.com/newville/ifeffit/blob/master/src/feff6/fovrg.f#L158> > > > The error is reported here: > > https://github.com/newville/**ifeffit/blob/master/src/feff6/**phase.f#L127<https://github.com/newville/ifeffit/blob/master/src/feff6/phase.f#L127> > > > 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 > practitioners. > > 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 > written. > > 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 > science. > > 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. > B > > > -- > Bruce Ravel ------------------------------**------ bra...@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 > ifef...@millenia.cars.aps.anl.**gov <Ifeffit@millenia.cars.aps.anl.gov> > http://millenia.cars.aps.anl.**gov/mailman/listinfo/ifeffit<http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit> >
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