Sequential GSAS

Sequential GSAS (using SEQGSAS & SEQPLOT) can be used to automate a fit refinement of diffraction data for a series of datasets using GSAS/EXPGUI. For example, you could use this to obtain refined lattice parameters from data collected while varying the temperature of the sample. One must first set up an initial refinement manually, but related datasets can then be refine automatically based on the values and parameters you select in the initial model.

Hints:

- Program is command line only, but can be accessed from EXPGUI, look in the ______ pull down menu.

- Data sets must be in a proper GSAS format.

- Data file names must be sequential. You will likely need to rename your files before starting. (for example, this type of batch conversion can be simply done using Automater on a Mac)

- File names must be in numerical sequence with some leading characters 

(example: file0.fxye, file1.fxye, file2.fxye, ... file11.fxye, file12.fxye... file100.fxye

1. Enhancements of SEQGSAS & SEQPLOT: SEQGSAS now will read raw data files until it runs out and then ask if "there are more". This is to allow SEQGSAS to run in a live data acquisition pipeline where one does Rietveld refinement on data as it is produced in an experiment varying temperature. SEQPLOT now has an "update" mode where new PVE files are read on demand ("U" option). SEQPLOT will now read 1000 PVE files; limited to 200 parameters. GENLES has been modified so that profile R values (Rp & Rpw) are put in the PVE file and the lattice parameters (a, b, c, etc.) with esds are also put in this file when varied. ASCII table output tweaked a bit to give 6 sig(?) figures; used to be 4. Raw data file names still must be in numerical sequence but no longer require any leading characters (although this is a good idea anyway) before the number (e.g. 25.dat, 26.dat, etc. is OK). Please note that SEQGSAS does not work for raw data sets that are not in "proper" GSAS format. Use CNVFILE to fix them if needed.