Version 8 (modified by toby, 10 years ago) (diff)


Installing GSAS-II on Windows

Prerequisites: Before GSAS-II can be installed on your computer, you must install two software packages: python and subversion. These packages are distributed in a number of forms and are discussed below. Note that at present GSAS-II is only distributed via subversion. If you work at an institution with a firewall that blocks downloading files from subversion (uncommon, but known), contact your networking support department or arrange to perform the download from another location. If you can help expand any of these instructions, discover new mechanisms for installing Python, or have problems getting this to work, please let me know.


Python is a computer scripting language, which means that one must have the Python interpreter installed on your computer to run a Python program. However, there are a number of Python packages required by GSAS-II that are not distributed within Python, so not just any distribution of the Python interpreter will do. For development, we use EPD, but expect the other distribution options described here will do fine. Python and all the required packages are open source, so you could, in theory, download the source code for each one and compile them yourself. Most Windows users are likely to prefer to use binary distributions and will prefer using a single download that provides everything they need. For that, select and download one of the packages below and follow directions provided on that site for installation. Note that GSAS-II is being developed with version 2.x of Python (2.7.2 as of December 2011) and has not progressed to version 3.x of Python. This is in part because not all the packages required by GSAS-II are fully supported on Python 3.x.

  • Enthought Python Distribution (EPD) is a commercially licensed Python package that features differing levels of support. Academic users may request a free license at To install, download the .msi file and click on it to invoke the windows installer. Note that this package can be installed without administrator privileges -- I think -- if you install it for only your own use. You may have to choose an install location that you own (a subdirectory of My Documents, for example.)
  • Free Enthought Python Distribution (EPDFree) is a light-weight and non-supported version of the EPD package, above. It contains all the packages needed for GSAS-II excluding PyOpenGL. To install, download the .msi file from URL and click on it to invoke the windows installer. (See note with regard to administrator privileges.) After installing EPDFree, you can install PyOpenGL from here. Run the !PyOpenGL3.0.1.win32.exe file. If you have more than one version of Python on your computer, make sure it installs OpenGL into the EPDFree version.
  • Python(x,y) is a free Windows (and Linux) Python distribution. It focuses on supporting the Qt GUI package, while GSAS-II requires Wx, but this distribution does offer Wx and all the other packages that GSAS-II requires, as far as we are aware. Note that when you install, you will either need to select to install all packages or else perform a customized installation to ensure that the Python packages required by GSAS-II are installed. To install, download the .exe file, run it and read the instructions.
  • ActiveState ActivePython This is commercial licensed software that includes a free version with no support. ActiveState? is well respected in the scripting community , but we have not tried this yet.


Subversion is a software version tracking system that allows you to download and update the GSAS-II software from the APS subversion server ( You can install a variety of different versions of this software, but the two we recommend for Windows are these:

  • TortoiseSVN incorporates Subversion capabilities into Windows. See the downloads directory and be sure to install the version (64-bit or 32-bit) appropriate for your version of Windows. Once TortoiseSVN is installed, follow these installation instructions
  • mini-svn kit: A 2.5 Mb zip file has been prepared that contains a minimal SVN package, along with a batch file for installing GSAS-II from the APS subversion server. Use these Installation Instructions? to use this kit.

Compiling Fortran Code

GSAS-II requires a small number of Fortran routines that are incorporated as Python packages (.pyd files). GSAS-II is distributed with these files compiled for a number of python versions, but if you are using something that does not match what we distribute, you may need to compile the Fortran routines yourself using the NumPy f2py routine and the compiler of your choice. Both G77 (32-bit Python only) and GFortran have been successful on the platforms we have tried.

To help with compiling the programs, use the python scons routine inside the GSASII\fsource directory. If you are lucky, this routine will find the needed compiler and python program, set all options correctly for you and run all steps needed to prepare the .pyd files. This is done by

(1) running cmd.exe to open a "DOS" window,

(2) use the volume name (when not C:) and the cd command to set your working directory to ...\GSASII\fsource and

(3) simply typing "scons" in the window.

If you need to change any options, type "scons help" to see a list of the possible command-line arguments and the values for the options. For testing, help can be used with command-line options to see how they will change the variables.