Version 4 (modified by toby, 10 years ago) (diff)


Installing GSAS-II on Mac OS X

Prerequisites: Before GSAS-II can be used on your computer, you must have two software packages installed, python and subversion. With 10.5 and 10.6, OS X comes with both installed, but alas, the supplied python versions do not include all the required packages. 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 Mac to run a Python program. However, there are a number of Python packages required by GSAS-II that are not distributed within Python so some software installation is required. Note the required WxPython package runs only in 32-bit python.

We do not have a lot of experience with options for loading the needed Python interpreter and packages on the Mac. The EPD package is what we use for code development. In theory, you might be able to load just the missing packages, but it is not clear how easy that is to do. Use of the Fink or DarwinPorts versions of Python is probably not a good idea -- the GUI and graphics will be shown in X-windows; if this indeed does work, the performance will be poor. Note that at this time, GSAS-II does not support Python 3.0 or greater and Python 2.7 is recommended.

  • Enthought Python Distribution (EPD) is a commercially licensed Python package that features differing levels of support. To install, download the .dmg file and click on it (if needed) to mount it. You will see the EPD.mpkg installer. Click on that to start the installation process. Note that admin privileges are required to load this package.
  • ActiveState ActivePython This is also commercial licensed software. There is a free version with no support. We have not used this yet.

It is probably possible to install the EPDFree package and then build the PyOpenGL package from source code, but this has not yet been attempted.


Subversion is a software version tracking system that allows you to download and update the GSAS-II software from the APS subversion server ( It is already installed in 10.5 (Leopard) and 10.6 (Snow Leopard) but not 10.4. Subversion likely can be found and downloaded for 10.4, but the latest EPD releases require 10.5 or later. While GSAS-II can probably be run on 10.4, this is probably a lot more work than one would like.

Compiling Fortran Code

GSAS-II requires a small number of Fortran routines that are incorporated as Python packages (.so 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 .so files. This is done by

(1) opening a Terminal or xterm window,

(2) using 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.


  1. Create a folder where you want to install GSAS-II.
  1. Download file file using this link:

or use this command:

curl >

  1. Move that file into the new GSAS-II folder
  1. Run the file by double-clicking on it or using the command "python"
  1. This creates a file that can be used to start GSAS-II either by clicking on the app or by dragging a file onto the app. Note that the app file can be dragged to the doc, but it cannot be moved to another folder. Instead, create an alias and move the alias where desired.

Errors from

The error messages from the are placed in a file named GSASIIerrors in the user's home directory

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