Hi Sandra,
On Sat, Apr 6, 2013 at 12:37 PM, Sandra Luber
Dear Matt Newville,
I do some fitting with ifeffit using EXAFS data generated by feff. I wonder how the R-factor is calculated. Unfortunately, I have not found any definition yet. Would it be possible that you write me how it is obtained? This would be great.
Thanks a lot.
Best regards Sandra Luber
The basic definition is R = Sum( |data - fit|^2 ) / Sum( |data|^2 ) The old Feffit document probably has the clearest definition, in its Chapter 5 (pages 16-20 of http://cars.uchicago.edu/~newville/feffit/feffit.pdf ). The definition and briefer explanations are also given in several of the tutorials on http://xafs.org/Tutorials. Thanks for reminding me to put this and related information into the Larch documentation! --Matt