Note that version 1.41 or later of EXPGUI should be used with the April 2001 releases of GSAS on all platforms (Version 1.41 is currently the alpha release version), due to changes in file formats and locations. The "stable" release should be used with older versions of GSAS.
EXPGUI is a graphical interface for the Los Alamos GSAS package. EXPGUI does two things: it can be used to directly modify the GSAS experiment file with a graphical user interface (GUI) and it can be used to invoke the programs inside the GSAS package such as EXPEDT, GENLES, FOURIER... These programs can be run from a menu or in many cases by pressing buttons. EXPGUI is written using the Tcl/Tk scripting language.
This web page describes the different actions that can be accomplished with the different panes and the contents of the menus. The table below contains links to the other web accessible documentation.
| GUI Sections | Least Squares | Phase info | Histogram info |
|---|---|---|---|
| Scaling info | Profile terms | Constraints | |
| Preferred Orientation | |||
| Installation Notes: | Unix | Windows | Customization |
| Tutorials: | TOF | CW Neutron | |
| Utilities: | LIVEPLOT | BKGEDIT | EXCLEDT |
| Messages: | Error | Warning | Informational |
| Other: | Introduction | Recent & Planned Improvements |
J. Appl. Cryst. article |
Citations. The appropriate citations to be used for GSAS and EXPGUI are:
If there is an error in the typed value, (for example if "1..0" is typed, or
"1.5" is typed where an integer is expected), these values are
not saved. In this case, the text is turned red, to indicate
that an error is present, as shown in the figure to the left, where "90.000x"
has been entered for alpha.
The edited version of the experiment file is written back out to
disk when the "File/Save" or "File/Save as"
menu bar options
are used. The File/Save operation is done automatically before any GSAS
programs, such as GENLES or EXPEDT, are run.
Since the GSAS experiment file is quite complex, values are grouped together by function, approximately following the outline of the EXPEDT program. Each set of values is given a "tabbed pane" on a window that has the appearance of a notebook (see below).
It does not make sense, however, to globally modify instrument-related parameters and flags for different histogram types. So global actions can be limited to a single class of histogram types (e.g. TOF, CW Neutron,...), which allows these parameters to be set for groups of similar histograms. Thus, if this mode is set to "All" the Histogram and Profile panes are disabled.
The setting for "Multiple Histogram Selection" mode is
displayed above each histogram selection box and is
selected using the "Multiple Hist. Selection" item on the
Options menu to create a submenu or by clicking on the display.
Note that another option in this "Multiple Hist. Selection"
submenu is an option "Group Phases Together" that controls how
EXPGUI treats phases having
the same profile type that is used when multiple histograms are selected. If
the "Group Phases Together" option is on, then the refinement flags for
all phases with the same histogram types are grouped together, when possible.
If this option is off, phases are treated separately.
If the left mouse button is used to click on the selection mode display,
the mode is cycled between the available modes. If the right mouse
button is used, the mode is reset, to disable multiple histogram selection.
GSAS programs are invoked either through use of the menu bar
Once the GSAS program has finished, if the program has modified
the .EXP file,
"File has been modified..."message box
similar to the one to the left is displayed (also see the more complete
discussion on the messages page.
Note that this message can be avoided if the
"Autoload EXP"
option is used.
Note that in both Windows-95 and Windows-NT, a file named EXPGUI.LCK is created while the GSAS program runs. The presence of this file is used to suspend the LIVEPLOT program, since LIVEPLOT has sometimes crashed when run at the same time as GENLES (no such problem has been seen in Unix). This file is deleted when the GSAS program completes.
In Windows-9x, the Winexec
package is used to execute a command that creates a DOS window.
The GSAS programs are then run by a batch file in this DOS window.
Due to limitations in Tcl/Tk & Windows, the DOS window runs independently
of EXPGUI, so the lock file (EXPGUI.LCK) is also used to suspend
EXPGUI. While EXPGUI is waiting, the
Please wait...
window shown to the left is displayed. When the GSAS program completes, the
lock file is deleted, the window automatically disappears and EXPGUI resumes.
Should a problem arise where the file is not deleted, EXPGUI can be resumed by
pressing the "Continue" button.
LIVEPLOT can now be enhanced to superimpose peak locations for
input unit cells or peaks from JCPDS/ICDD entries.
See the
LIVEPLOT customization information
or read file expgui_cfg.html in the gsas/tcl/doc directory.
GSAS data, experiment and instrument parameter files are expected to have a format with exactly 80 characters per line followed by a carriage return and then a linefeed (82 characters total per line). Files in this format can be read in "Direct Access" mode. Recent versions of GSAS will attempt to detect and repair files that are not in this format, but if the file is incorrectly formatted and by chance the length of the file is divisible by 82, the problem in the file format will not be detected. The Convert menu in can be used to convert files into the correct format. The original version of the file is retained and renamed.
On the dialog the number of history records to be retained is specified. Also, after records have been deleted, the remaining records can be renumbered starting with 1, so that the 999 record limit is not reached.
GSAS is written by Allen C. Larson and Robert B. Von Dreele, MS-H805, Los Alamos National Laboratory, Los Alamos, NM 87545. Problems, questions or kudos concerning GSAS should be sent to Robert B. Von Dreele at vondreele@lanl.gov EXPGUI is written by Brian H. Toby of the NIST Center for Neutron Research, Brian.Toby@NIST.GOV with help from Jonathan Wasserman.
GSAS is Copyright, 1984-2000, by the Regents of the University of California. The GSAS software was produced under a U.S. Government contract (W-7405-ENG-36) by the Los Alamos National Laboratory, which is operated by the University of California for the U.S. Department of Energy. The U.S. Government is licensed to use, reproduce, and distribute this software. Permission is granted to the public to copy and use this software without charge, provided that this notice and any statement of authorship are reproduced on all copies. Neither the Government nor the University makes any warranty, express or implied, or assumes any liability or responsibility for the use of this software.
The author of EXPGUI is a U.S. Government employee which means that EXPGUI is not subject to copyright. Have fun with it. Modify it. Please write new sections and make them available to the rest of the world.
Neither the U.S. Government nor any author makes any warranty, expressed or implied, or assumes any liability or responsibility for the use of this information or the software described here. Brand names cited herein are used for identification purposes and do not constitute an endorsement by NIST.