Version 2 (modified by toby, 4 years ago) (diff)


Installing GSAS-II on Windows the Hard Way

Overview: Installing GSAS-II requires three things: installing a Python distribution, a download package (subversion) and the actual GSAS-II code.

Use these instructions if you are using 32-bit Windows, or a version of Windows older than Windows-7 or want to install Python yourself.

There are at least three different distributions of Python that can be used with GSAS-II.


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 several Python packages required by GSAS-II that are not distributed within the standard Python distribution, so not just any version of the Python interpreter will do for GSAS-II unless compatible versions of the required packages are available.

  • Enthought Canopy is a Python distribution from a company that has done quite a bit of work in Python and made that available to the community. We have not done any testing with this for a while, but have done so in the past and expect it to work fine.
  • 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.
  • We used to recommend the predecessor to Canopy, the Enthough Python Distribution (EPD) which came in two flavors, one free and one by subscription. Use of this is not recommended, but might be needed with really old computers (say Windows-XP). There are older instructions here for installing GSAS-II using the Enthought EPDfree package?, but this is no longer recommended.


Subversion is a software version tracking system that allows you to download and update the GSAS-II software directly 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 -- this must match the OS or it will not run. Once TortoiseSVN is installed, follow these installation instructions

or (not recommended)

or (not recommended)

  • If you are unable to access the subversion server for some reason and must use a conventional download (note that in all the cases so far where people have been seemed to be blocked have turned out to be fixed through addition of a proxy server), you can download a snapshot of the current version of GSAS-II using this URL:

This will supply all the GSAS-II files in a zip archive. The contents of this archive can be moved to the location where GSAS-II will be installed.

We discourage use of this because you will need to repeat the entire download every time you want to upgrade; GSAS-II is updated often (sometimes daily!).

Compiling Fortran Code

Normally you will not need to compile anything. The GSAS-II distribution contains compiled .pyd (library modules) needed by a 32-bit or a 64-bit Python version 2.7 interpreter for Windows. However, if you are working with an unusual python interpreter or are doing GSAS-II development, compilation instructions can be found here.