Hi All, I suppose I need to remind folks about where to find the new GSAS. It is always at http://www.ccp14.ac.uk/. The Windows version was put there on Friday 4/16/04. Bob Von Dreele
________________________________ From: Marcelo J.G. Silva [mailto:[EMAIL PROTECTED] Sent: Sat 4/17/2004 7:56 AM To: [EMAIL PROTECTED] Hello Bob Von Dreele and all, I am Marcelo Gomes da Silva, PhD Student at PennState. About this new version, is it avaliable for downlaod already? If so, where? Appreciate everybody's attention. Marcelo ----- Original Message ----- From: "Von Dreele, Robert B." <[EMAIL PROTECTED]> To: "Rietveld list" <[EMAIL PROTECTED]> Sent: Friday, April 16, 2004 11:18 AM > Hi all, > There is a new version of GSAS for Windows; Linux to follow soon. The changes are: > > GSAS News....... > April 15, 2004 (tax day in USA) > 1. A small cosmetic fix to the g-value editing routine. > 2. There is now an option in histogram editing to set aside a certain fraction of > the > profile points in a powder pattern to calculate an Rfree and Rwfree. This replaces > the > old 'S' option (which didn't work anyway). The Rfree & Rwfree values appear in the > .LST > file (not on screen) and in the EXP file. In my initial tests these seem to follow > the > Rp & Rwp values closely through the entire course of a refinement but maybe you all > will see wilder behavior in your refinements. Note that you set two things for this > - > one is the percentage of points to set aside (1-10%) and a random number seed. The > seed > ensures that the selection of points remains the same for all runs of POWPREF; this > will change if seed is changed or if profile limits & excluded regions are changed. > If you want to use this it should be set very early in the analysis; setting it for > just the final refinement cycles somewhat defeats its purpose. > 3. After some experience, I've had to set the integration controls for the Finger, > Cox > & Jephcoat axial divergence profile function back to where I had them a few years > ago. > Too many ripples. New version will be a bit slower but more accurate. > > Please let me know of your experiences with Rfree, especially if it differs much > from Rp. I'd like to know circumstances when this happens to get an idea of how > useful a diagnostic it is. I'm thinking of doing the same for the single crystal > histograms - any comments? > Enjoy, > Bob Von Dreele > >
