[Ifeffit] Statistical errors in linear combination fits

Bruce Ravel bravel at bnl.gov
Thu Aug 11 15:43:36 CDT 2016

On 08/11/2016 04:31 PM, Joshua Kas wrote:
> I was wondering if it is possible to pass a value for the uncertainty in
> the data to Athena when doing linear combination fits. We have
> calculated chi^2 values using a simple estimate of the statistical
> uncertainty, and find that our values differ by several factors of 10
> when compared to the reported values from Athena. I assume that this has
> to do with value of the uncertainty that Athena is using, but I
> certainly could be mistaken. In any case, the reduced chi^2 reported by
> Athena is much smaller than 1, while the fit is off by fairly large
> amounts compared to any reasonable estimate of the statistical error.

Not so easy with Ifeffit, quite easier with larch.  It's on my to do 
list, but has not yet been implemented in Athena.


  Bruce Ravel  ------------------------------------ bravel at bnl.gov

  National Institute of Standards and Technology
  Synchrotron Science Group at NSLS-II
  Building 743, Room 114
  Upton NY, 11973

  Homepage:    http://bruceravel.github.io/home/
  Software:    https://github.com/bruceravel
  Demeter:     http://bruceravel.github.io/demeter/

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