GSAS-II Home Page

Welcome to the home page for GSAS-II, a unique and comprehensive open source Python project for determination of crystal structures and diffraction-based materials characterization for crystalline solids on all scales, from perovskites through proteins, using both powder and single-crystal diffraction and with both x-ray and neutron probes. Refinements can combine measurements from laboratory and synchrotron x-rays, as well as constant wavelength or time-of-flight neutron sources. It provides structure solution and refinement, as well as extensive visualization capabilities.

Home Page Contents

• 1. Installing GSAS-II: Overview
• 2. GSAS-II Documentation
• 3. Mailing List
• 4. Reporting GSAS-II Bugs
• 5. Customizing GSAS-II
• 6. Help: GSAS-II will not start
• 7. Notes for GSAS-II Developers
• 8. Miscellaneous GSAS-II Links

Tip

Please help us by citing:

Toby, B. H., & Von Dreele, R. B. (2013). “GSAS-II: the genesis of a modern open-source all purpose crystallography software package”. Journal of Applied Crystallography, 46(2), 544-549. doi:10.1107/S0021889813003531

Note that some sections of the program utilize externally provided codes or reference later work, with citations provided as they are used. Please cite them as well.

GSAS-II is made available for free use (see license) with open access to the source code.

Also, please do sign up for the GSAS-II mailing list see below. We add new features to GSAS-II quite frequently, so we may break things from time to time (see bug reporting). Be sure to use the Help-->Update capability frequently to stay abreast of new features and fixes as they are added and please make sure to use the latest version before reporting a bug to us, but please do report bugs.

Installing GSAS-II: Overview

There are several different ways to install GSAS-II, as are outlined below. Most people will use the GSAS2FULL installer

Installation information:

• 1. Installing GSAS-II: Overview
  • 1.1. GSAS2FULL installer
    • 1.1.1. Windows
    • 1.1.2. MacOS and Linux
    • 1.1.3. GSAS2FULL Additional Details
      • 1.1.3.1. Windows GSAS2FULL Installation Details
        • 1.1.3.1.1. Notes
      • 1.1.3.2. MacOS GSAS2FULL Installation Details
      • 1.1.3.3. Linux GSAS2FULL Installation Details
  • 1.2. GSAS2PKG Conda Package
  • 1.3. Installing GSAS-II with separate Python Installation
  • 1.4. Installing directly from GitHub
    • 1.4.1. Installing GSAS-II for code development
      • 1.4.1.1. Create a GitHub account
      • 1.4.1.2. Establish a connection
      • 1.4.1.3. create a fork of GSAS-II
      • 1.4.1.4. Install GSAS-II from your forked copy
        • 1.4.1.4.1. Install directly from your forked copy
        • 1.4.1.4.2. Repurpose a standard GSAS-II installation
      • 1.4.1.5. Make changes and submit them
    • 1.4.2. Code development tip
  • 1.5. Older installers
  • 1.6. Installation details
    • 1.6.1. Compiling GSAS-II
    • 1.6.2. Customized Python Installation
      • 1.6.2.1. conda
      • 1.6.2.2. pip
      • 1.6.2.3. homebrew
      • 1.6.2.4. Distro-supplied packages
    • 1.6.3. Web Proxies

GSAS-II Documentation

While there is no manual for GSAS-II, there is quite a bit of web-based documentation, as listed below.

• 2. GSAS-II Documentation
  • 2.1. Tutorials
  • 2.2. Help pages
  • 2.3. Developer’s Documentation
  • 2.4. Scripting Documentation
  • 2.5. Crystallography/Powder Diffraction Intro

Mailing List

If you use GSAS-II, please join the mailing list so we can tell you about what is new and changing.

• 3. Mailing List
  • 3.1. Subscribing
  • 3.2. Using the list

Reporting GSAS-II Bugs

If something is not working properly in GSAS-II, please let us know. If we don’t know its broken, its not going to be fixed. Information on how to report bugs is here.

• 4. Reporting GSAS-II Bugs
  • 4.1. What to report
  • 4.2. How to report

Customizing GSAS-II

There are many options within GSAS-II that allow you to tailor aspects of the program to operate differently. These are described here. Options are available to change how powder diffraction refinement results are plotted or change defaults used in different parts of the program, , for example.

• 5. Customizing GSAS-II

Help: GSAS-II will not start

If there is a bug in GSAS-II, check for updates (using the Help/Update menu command) and if the bug is present in the latest version, please report it (see section above on reporting bugs). Should GSAS-II fail to start after an update, then there are alternate ways to update GSAS-II, as discussed below.

• 6. Help: GSAS-II will not start
  • 6.1. On windows
  • 6.2. On MacOS and Linux

Notes for GSAS-II Developers

We encourage you to improve GSAS-II or to use the code in your own projects. Some starting information is here:

• 7. Notes for GSAS-II Developers

Miscellaneous GSAS-II Links

Other things related to GSAS-II can be found here.

• 8. Miscellaneous GSAS-II Links
  • 8.1. Honoring Bob Von Dreele on his 80th Birthday