Hi Daniel, On Wed, 11 Dec 2002, Daniel Grolimund wrote:
In case I am using non-regularly spaced k-chi data, the plot of the chosen Fourier Transform Window is not represented correctly using the command plot(group.k, group.win)].
Is there a way to get around that (except using interpolated and therefore regularly spaced) data?
Funny you mention this, I just noticed the same problem myself over the weekend. Currently, fftf() writes out the window function assuming the 0.05 Ang-1 grid, regardless of the input k-array. I believe this is fixed (that is, the group.win array corresponds to the group.k array!) in my latest test version. I still need to test other fixes in this version, but hopefully I'll get it out early next week.
Further, in a earlier version one had to use ikwindo = n to specify the Fourier Transform Window type. In ifeffit the termology kwindow = aaaaa is used. In addition to 'kaiser' and 'hanning' are there any other options for kwindow ?
Oh right. This is one place where Ifeffit and Feffit are different. Feffit's 'ikwindo = 2' caused some headaches (no one could remember them!) so 'kwindow=hanning' etc seemed better (if english-centric) for ifeffit. Other window functions are 'parzen' (linear sills), 'welch' (quadratic sills), and 'sine' (a sine wave over the whole range), and 'gaussian' (which is really weird: centered at dk2, with full width of 1/dk1, someone asked for it many years ago, it could probably be improved!). The next version of ifeffit will also have a window() command to make window functions without actually doing the FTs. --Matt