Actually, I looked at Luca's little "show" & was sufficiently interested that GSAS will now plot sqrt(I) style plots. There is one "problem" - the value of "I" can be negative particularly after a background subtraction. These must be suppressed to zero for this plot to work - thus there is a small risk of something getting hidden. Anyway - the new version will be out in a day or two (after I make sure there are no bugs introduced by this!)
R.B. Von Dreele IPNS Division Argonne National Laboratory Argonne, IL 60439-4814 -----Original Message----- From: Luca Lutterotti [mailto:[EMAIL PROTECTED] Sent: Wednesday, February 21, 2007 2:59 PM To: rietveld_l@ill.fr Subject: Re: Powder Diffraction In Q-Space Alan, if it is trivial to plot in the square root I presume it is already available in Topas as well GSAS and Fullprof just to mention few. And if it is so trivial and already available as a button options why no one is using it. Why every time I look at a paper with a Rietveld refinement I can only appreciate the big peaks and why the residuals are so little meaningful at end? Every one can choose what he prefers obviously, but why all (without exceptions) are using not exactly the best way to just do a plot? Should not be trivial? Conversion from 2theta - d -1/d is trivial in MY OPINION. This is really a problem of the programmer not of the users (in a Rietveld list). Constant step or variable step? Why it should influence the conversion except for the speed of the conversion. I am using fast fourier transform in my program for computing peak profiles directly from distribution of crystallites and microstrain; I don't assume any constant step, but seems like I can do it. And this step or FT has really nothing to do with the original post of Klaus-Dieter who was focusing on just asking people if we can try to get used to a common way to plot data different from the conventional one. There are obviously favorable points and cons. Why we cannot discuss it. Seems like for the Rietveld users is not so trivial. Oh, and no one is setting up web sites just to show opinions.........may be these were already there....... Cheers, Luca On Feb 21, 2007, at 8:11 PM, AlanCoelho wrote: > > Whether a program has a button to display data as a function of 1/d > or a > button to take the square toor of intensities is trivial to the > point of not > being talked about much less setting up web sites to get opinions. > > The only point worth talking about is how a conversion from 2Th to > 1/d is > done in regards to takeing the fourier transform of a powder pattern. > > alan > > > -----Original Message----- > From: Joerg Bergmann [mailto:[EMAIL PROTECTED] > Sent: Thursday, 22 February 2007 4:30 AM > To: rietveld_l@ill.fr > Subject: Re: Powder Diffraction In Q-Space > > It's a principle of software design not to presume any kind of > equidistant data. Unfortunately, file formats for non-equidistant data > are seldom. So I could not implement any in BGMN, until now. But, in > principle, there is no restriction. > > Regards > > Joerg Bergmann > > >
