Hello,

I hope you don't mind that I am sending my responses to your questions to the Ifeffit mailing list. They seem of sufficiently general interest that I think the Ifeffit list would be interested.

I don't. :)

MS> Another detail which kind of puzzles me: whenewever I use a MS> Kaiser-Bessel window and increase the weight, the *plotted* MS> limits of the apodization window shift away from the positions MS> defined in the command window (e.g., for positions set to 2 and MS> 13 Å-1 in the command window and a weight dk = 1, the plotted MS> apodization limits are shifted to 1 and 14 Å-1).

I am a bit confused by the numbers you give in that they are not consistent with what I observe when I make a plot displaying a Kaiser-Bessel window. Here is what I observe:

For a window defined by kmin=2, kmax=18, and dk=2, the first non-zero value of the window is at k=1 and the last non-zero value is at k=19. In general terms, the first non-zero value of the Kaiser-Bessel window is at kmin-dk/2 and the last is at kmax+dk/2.

OK, I wanted to make the distinction between the first and last non-zero values as they *appear* in the graphic window, and the numerical values as stored as internal values in the software. I assumed that these values were not the same. This assumption, but was -partly - justified by the wollowing reason: If I keep kmin and kmax constant and increase dk, I increase the k-range covered by the K.B. window, and this should result in an increase of the number of independent points. What I observe is that the number of independent points calculated by artemis is *not* affected by dk, suggesting that the FT range remains limite to [kmin, kmax].

The bottom line is that you may want to set kmin a bit higher so that kmin-dk/2 is at the point where you want the window to start. Note that setting dk to 0 is probably *not* what you want to do, although it is probably worth doing so just once to see what happens to the K-B window.

I did: the first and last non-zero values plot exactly at kmin and kmax.

MS> A final 'cosmetic' suggestion: would it be possible in future MS> versions of artemis, to plot both the amplitude and real part, or MS> amplitude and imaginary parts of experimental and simulated MS> chi(R) together?

You are not the first person to ask for this, Michel, but the last time this came up, Artemis was much less far along.

Sorry for being late...

So, let me put it up to discussion among the folk on this mailing list. What should Artemis do?

1. Allow the user to select one or more parts of chi(R) (or chi(q) for that matter) and plot each of those parts for each of the things selected in the "Paths" list. 2. Allow the user to somehow specify which parts of chi(R) to plot for the data, the fit, and each path individually. (This would make the interface somewhat more complex.) 3. Continue to work exactly as it works now. 4. Something else entirely.

Basically in a simulation, both the amplitude and the phase of selected paths may be (shoud be?) compared. Therefore, I would select (1) (but let me reiterate that this is not a priority to me). Thanks in advance, and happy new year, Michel Schlegel