Hi Everyone, Here is an excerpt from the GSASNEWS.TXT with recent stuff. Please give the new stuff a try and let me know particularly about bugs & "features" Bob Von Dreele GSAS News....... April 11, 2001 Now things are better: New versions of both Windows and Linux-beta GSAS have been placed on the ftp site. Major fixes include: 1. The error that caused harmonics texture to fail was identified and fixed. The g77 library routine for atan2 didn't know what to do with atan2(0,0). 2. The atom constraints now allow 500 individual constraints with 500 terms each. 3. The EXP and raw data file formats for both Windows and Linux are fixed-length 82 character direct access form. They are directly interchangable between the two OS's. 4. PC-GSAS.EXE now works in all MS Windows versions both 9x and NT derivatives. 5. In anticipation of refinement of some very large structures, the parameter numbers shown in GENLES under 'pn' are now in hexadecimal format. 6. There is a new overall parameter for "radiation damage" with X-ray powder data only. This is probably only useful for multidetector or multiple scan data sets. There is one parameter for each phase in each histogram and there is an offset value to put the scans on the same "exposure time" scale. The exposure time scale is assumed to be porportional to 2-theta - offset. 7. The Linux version was compiled and linked on RedHat 7.0 using the backward compatibility libraries. It should run in RedHat 6.2 or newer and other compatible Linuxes. 8. The Windows version makes use of GRWin libaries and pgplot to produce a nice graphics window. Multiple plots can be seen in this window - each can be resized, scrolled, zoomed, etc. as well as copied & pasted elsewhere. 9. More than one GSAS program can open a given EXP file simultaneously. There are no checks on reasonable access to this file so use this "feature" with care. It is useful to run POWPLOT while GENLES is running, but if you do EXPEDT twice on the same EXP file it's probably ruined! If people get into a lot of trouble over this I can fix it with access "rules". 10. The "VERSION" record in the EXP file now contains the "load date" date/time for the GSAS routine that initially creates it. This is to help Brian Toby distinguish between various GSAS versions on a fine scale. 11. Brian Toby is preparing a new SGI version - you SGI fans should look for it soon. 12. Brian & I are exploring the use of proper "Install" packages for GSAS. Some remaining mysteries: 1. Cursor/keyboard behavior is oddly different in Win9x, WinNT & Linux. 2. Empty files (expedt, genles, etc.) are created in Windows under certain conditions. 3. Program windows close automatically at the end of a run - may not be desirable. 4. ????? March 16, 2001 OK, some things went wrong. A few more fixes for both Linux & MS-DOS/Win versions ... 1. The output from RAWPLOT of the fitted profile was modified a bit. 2. The number of integration terms was changed for the Finger, Cox & Jephcoat peak shape functions (#3 & #4 for CW radiation). This removes the tendency to have "wiggly" calculated profiles for certain very asymmetric peaks. The cost is about 20% in run time for GENLES. 3. I've had to revise the restrictions on the number of atom constraints. The limits now are 200 constraints and 500 terms each. The previous version had 2000 constraints and there were complaints that EXPEDT wouldn't load in WinNT/2000 (it was fine on my 128Mb Win98 machine and in Linux). The old EXPEDT was about 20Mb, this new version is about 5.5Mb and should be easier to load on smaller machines. This may have to be revisited again. March 11, 2001 New releases of both the "MS-DOS" and "LINUX" versions of GSAS are now available. Changes & bug fixes: 1. Each powder histogram may now have a weight factor. By default the value is 1.0; it can be changed in the histogram editing menu after which POWPREF must be run to implement it. This can be used to change the relative weighting of different powder histograms or to "shift" a high chi**2. Caution is advised in using this option. 2. The number of terms in each atom constraint is now 500; it was 100. This has not been explicitly tested but should work. 3. An error in lattice parameter constraints has been fixed. 4. The maximum size of Fourier maps is 5M elements. The size of a section is now arbitrary; this limit used to be 23000 imposed in FORPLOT. 5. An attempt has been made to fix a bug in the twin calculation routine. The old one only seemed to work for neutron magnetic structures. It should be noted that refinement of a "Flack" parameter can be done with the twin option by entering a twin element with the inversion matrix. 6. RAWPLOT now has an option to output the fitted profile appended after the peak fitting results. 7. The torsion angle restraint has been changed to have pseudopotential representation for the angle. 8. The output of several restraints have been changed to be more consistent with each other.
