[Ifeffit] statistical parameters
stefano.ciurli at unibo.it
Wed Dec 14 11:16:21 CST 2005
>According to what you said above, Nvar = 7, so nu=24.83, which is much
>closer to 23.54.
of course. My mistake. But still...
>That still seems bigger than rounding errors, though.
that's what I am saying...
>Here is my understanding of Ifeffit, but I am sure Matt can elaborate.
>Background removal uses the integer part of dk*dr*2/pi+1 to determine
>the number of knots. Fitting uses dk*dr*2/pi as a real number to
>determine Nidp. In any case, that's what Artemis reports when you ask
>it how many independent points in a project. My memory is that I
>checked it against Ifeffit's report of Nidp.
Not sure I fully follow, as I am not talking about background
removal, but in any case, shouldn't the ratio between chi^2 and
reduced-chi^2 be an integer number, whichever? Plus, I have found a
few documents in which Matt reports Nidp as 2dkdr/pi, some others in
which he reports 2dkdr/pi+1. In SK's thesis, which is available on
the net (thanks Shelly :-)) she says +2. I was simply wondering which
is the right formula used in IFEFFIT, and if it is different from
what reported in Stern, Phys. Rev. B, 1993, 48, 9825-9827, why it is
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