[Ifeffit] (Reposted) K-space vs R-spce fitting

Matt Newville newville at cars.uchicago.edu
Sat Sep 11 06:40:16 CDT 2010

Hi Juan,

The data and model are  k-weighted and multiplied by the chosen window
function before the least-squares fit.  So yes, as you see, the choice
of dk will change a k-space fit.  I wouldn't expect it to change the
results by a huge amount no matter how the fit was done.  I would
suspect something else is going on, but it's hard to tell much without
more details.


On Fri, Sep 10, 2010 at 8:36 PM, Lezama Pacheco, Juan Salvador
<jlezama at slac.stanford.edu> wrote:
> Hi Matt:
>      Thanks so much for your answer. Let's see if I can make it more clear this time.
> Should dk have an effect on the actual fit, if it is performed in k-space?
> As I said, I found out that by changing dk (in k space) (keeping (kmin,kmax) constant) values change
> around 15%, so that tells me the actual fitting range is (kmin-dk/2,kmax+dk/2) is that so?
> Juan
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