1.8.1. Installing Externally-developed Software

There are several publicly-available programs where GSAS-II provides an interface, but the software authors understandably would prefer that their software be downloaded by users directly from the authors’ web sites, rather than be distributed as part of GSAS-II. Details on the installation of these optional programs is discussed below. Note that all are optional. Many users will not use any of them and it would be uncommon that anyone to use all of them.

1.8.1.1. Dysnomia

Computes enhanced Fourier maps with Maximum Entropy estimated extension of the reflection sphere.

The appropriate zip/dmg/tar file must be downloaded from https://jp-minerals.org/dysnomia/en/ and the directory Dysnomia from that download must be placed in one of the following locations:

  • the user’s home directory (~/.),

  • the directory ~/.GSASII or

  • the GSASII directory where GSAS-II has been installed (this will be where the GSAS-II Python files are found).

Tip

For Windows the user’s home directory, ~, is usually taken from the USERPROFILE setting or a combination of HOMEPATH and HOMEDRIVE, so these directories will usually have form C:\Users\<YourUsername> or C:\Users\<YourUsername>\.GSASII. (Replace <YourUsername> with the directory name on your computer.)

1.8.1.2. RMCProfile

Provides large-box PDF & S(Q) fitting. The GSAS-II interface was originally written for use with release 6.7.7 of RMCProfile, but updates have been made for compatible with 6.7.9 as well. RMCProfile must be downloaded by the user from http://rmcprofile.org/Downloads or https://rmcprofile.pages.ornl.gov/nav_pages/download/

For Mac and Linux systems, one has some flexibility on where one installs RMCProfile, on MacOS the only install location for RMCprofile where the software is configured to run is the system Applications directory. First, the configuration variable rmcprofile_exec, if defined, is checked as a location for the RMCprofile program. If that does not locate the program, On Windows and Linux, the location of the GSAS-II Python files, the location of the GSAS-II binaries, the current working directory (where the GSAS-II .gpx file is located) and the location where Python is installed, as well as the entire system path is searched for rmcprofile or rmcprofile.exe. On MacOS, the only location where the rmcprofile executable can be found is /Applications/RMCProfile.app/Contents/MacOS/exe.

See routine GSASIIpwd.findrmcprofile() for details on finding the RMCprofile program.

1.8.1.3. fullrmc

The fullrmc program is a modern software framework for large-box PDF & S(Q) fitting. Note that the GSAS-II implementation is not compatible with the last open-source version of fullrmc, but rather the version 5.0 must be used, which is distributed only as compiled versions and only for 64-bit Intel-compatible processors running Windows, Linux and MacOS. Download this as a single executable from website https://github.com/bachiraoun/fullrmc/tree/master/standalones. GSAS-II will offer to download and install this software into the GSAS-II binary directory when the fullrmc option is selected on the Phase/RMC tab.

The configuration variable fullrmc_exec, if defined, is checked as a location for the fullrmc program. If that does not locate the program, the location of the GSAS-II Python files, the location of the GSAS-II binaries, the current working directory (where the GSAS-II .gpx file is located) and the location where Python is installed, as well as the entire system path is searched for rmcprofile or rmcprofile.exe. On MacOS, the only location where the

See routine GSASIIpwd.findfullrmc() for details on finding the fullrmc program.

1.8.1.4. PDFfit2

For small-box fitting of PDFs; see https://github.com/diffpy/diffpy.pdffit2?tab=readme-ov-file#-diffpypdffit2. This software is no longer developed, but it is being maintained with respect to new Python versions.

The PDFfit2 developers recommend installing via conda, but it appears that pip installation is also possible. See https://pypi.org/project/diffpy.pdffit2/ for more information. It is possible to install PDFfit2 into the same conda environment that GSAS-II uses and if that is done, GSAS-II will use the package, but it is probably best to use a separate Python environment for PDFfit2, so that there is no possibility for conflict between package versions. When GSAS-II is run from a Python installation that includes the conda package manager (which is the case with the GSAS2MAIN installer), the GUI will offer an option to install PDFfit2 into a separate environment when the PDFfit2 option is selected on the Phase/RMC tab. This will define the configuration variable pdffit2_exec as the Python image where PdfFit can be imported using from diffpy.pdffit2 import PdfFit. Routine GSASIIphsGUI.checkPDFfit() is used to install PDFfit2. Note that a completely separate Python installation can be used for PDFfit2 and then pdffit2_exec should be defined as the Python image to run PDFfit2 using that Python command.

When PDFfit is used, routine GSASIIpwd.findPDFfit() is used to locate PDFfit. This is done using configuration variable pdffit2_exec and if that is not available, it is checked if PDFfit can be run within the Python interpreter that is already running GSAS-II. Note that PDFfit is run from GSASIIpwd.MakePDFfitRunFile().