2019 ORNL Total Scattering School, Diffpy-cmi demonstrations

This contains several demonstrations of Diffpy-CMI.

This project is both a binder project, and a set of pure python files.

For running the pure python files locally on your machine, you will first need to install the Diffpy-CMI packages.

Otherwise, you can run them with no additional software installation in your browser using binder (link above).

For installation of Diffpy-CMI in Unix based (Linux and Mac OS) systems

1. Install some version of Conda Python 3:

   • Miniconda is recommended, and can be found here:

     https://docs.conda.io/en/latest/miniconda.html

2. Install Diffpy-CMI

   • Open a Unix terminal

   • Create a new environment, and install Diffpy-CMI wihin it, using the following command:

     conda create -n diffpy --override-channels --channel defaults --channel diffpy diffpy-cmi

     • Enter y when prompted to install the relevant packages.

   • Activate your new environment with

     conda activate diffpy

3. Download and unzip these example files to a meaningful directory.

   • Navigate to wherever you have placed the files using cd /path/to/files

For installation of Diffpy-CMI in Windows systems

Only Windows 10 is currently supported, and Administrator rights are required.

1. Install the Windows Subsystem for Linux (WSL)

   • Instructions for this can be found here:

     https://docs.microsoft.com/en-us/windows/wsl/install-win10

   • You can choose which version of Linux you'd like to use, but Ubuntu is recomended.

2. Install an Xserver for plotting data.

   • VcXsrv is a good option, and can be found here:

     https://sourceforge.net/projects/vcxsrv/

3. Start your Xserver

   • Left click the Windows start button (Windows flag in lower left corner)
   • Type "xlaunch"
   • Right click on the xlaunch icon and select "Run as Administrator"
   • In the dialog window that opens:
     • Select "Multiple windows," enter -1 in the Display number field, and click "Next"
     • Select "Start no client," and click "Next"
     • Do not change any settings here, and click "Next"
     • If you would like your Xserver to start every time Windows boots up:
       • Click "Save configuration"
       • Navigate to C:\ProgramData\Microsoft\Windows\Start Menu\Programs\StartUp
       • Save the file as config.xlaunch
       • If you choose not to save a config.xlaunch file here, you will need to start your xserver after each reboot manually.
     • Click "Finish"

4. Tell WSL how to connect to your Xserver

   • Open a WSL command prompt

     • If you installed Ubuntu, click the Windows start button, type Ubuntu, and press enter.

   • Enter the following command:

     echo 'export DISPLAY=localhost:0' >> ~/.bashrc

5. Install some version of Conda Python 3:

   • Miniconda is recommended, and can be found here:

     https://docs.conda.io/en/latest/miniconda.html

   • Be sure to download the Linux (not Windows) version of whatever conda python you choose to use!

6. Install Diffpy-CMI

   • Open a WSL terminal

   • Create a new environment, and install Diffpy-CMI wihin it, using the following command:

     conda create -n diffpy --override-channels --channel defaults --channel diffpy diffpy-cmi

     • Enter y when prompted to install the relevant packages.

   • Activate your new environment with

     conda activate diffpy

7. Download and unzip these example files to a meaningful directory.

   • Navigate to wherever you have placed the files using cd /path/to/files

For older versions of Windows, a Linux virtual machine (VM) can be created. VirtualBox is a good, free, option for doing this, and can be found here: https://www.virtualbox.org/

Once this is installed, and the VM running, follow the instructions above for Unix based installation.

Running the examples

• Tutorials are meant to be run in order

• The relevant files are python files, of the form *.py

• Files contain extensive comments.

• Open a Unix or WSL terminal, and activate the relevant environment with

  conda activate diffpy

• Navigate to a example directory, for example, type cd ./example_1 for example 1

• A example can be run in one of two ways:

  • Entering python example_1.py directly in your terminal
  • In an IPython session:
    • Enter ipython in your terminal. This will start an interactive python interpreter.
    • Enter %run example_1.py

When in doubt, ask!