[Ifeffit] Re: I should be able to find this somewhere...

[Matt Newville]

HI Matthew,

It may help to diagnose the possible problem (either with Artemis or
perhaps with the fit?)  if you plot the residuals while plotting the
Real or Imaginary part of chi(R) instead of the Magnitude of chi(R). 
That is, with the Real or Imaginary parts, the residual should be more
easily interpretable, as it really will be Data-Fit.    FWIW, in
principle the magnitude of the residual could be larger than the data
if the best fit is very far out of phase with the data.  That would
give a terrible fit, of course.

--Matt