[Ifeffit] Rebinning

[Matt Newville]

Hi Carlo,

Thanks!!  That's wonderful.  It seems like this should be an
option in spline() and bkg_cl(), and possibly in pre_edge().  I
admit to being still a little confused by the goal of the
rebinning, especially with respect to loss of resolution.  It
seems like to use this script, you need to do two things:
  1. select an E0.   The data will be put at energies that
     will give an even k-grid with this e0.  I think it's 
     inevitable that if e0 changes, you might want to re-bin. 

  2. assume that the k-grid is small enough that the 
     measurements at independent energies are within the
     acceptable energy resolution that they can be 
     simply summed.

Is that right? 

Would it be OK with you (and everyone else) to have a weighted
average replace the boxcar average?  For example, at k=12,
[E(k+0.05) - E(k)] = 5eV, which is larger than normal energy
resolutions, so the boxcar average might wash out the high-k
EXAFS, no?  It might be better to convolve the spectra with a
lorenztian reflecting the incident energy resolution (probably
defaulting to 1eV).  Does that seem OK or is there something eles 
going on? 

Anyway, thanks!!

--Matt