1. Installation

This section will guide you through installing the ARMI Framework on your machine.

1.1. Prerequisites

These instructions target users with some software development knowledge. In particular, we assume familiarity with Python, virtual environments, and Git.

You must have the following before proceeding:

• Python 3.6+ (preferably 64-bit)

• Git

• MS Windows or Linux operating system

1.2. Preparing a Virtual Environment

While not required, we highly recommend installing ARMI into a virtual environment to assist in dependency management. In short, virtual environments are a mechanism by which a Python user can maintain separate sets of Python packages for various applications on the same machine. This prevents dependencies from various tools conflicting with one another. ARMI has a lot of requirements and may conflict with other libraries unless you do this step.

Start a terminal and navigate to the directory you’d like to install ARMI into. To create a new virtual environment, use a command like:

$ python -m venv armi-venv

The result is a folder named armi-venv, which contains a minimal set of Python packages, and a set of scripts for activating and deactivating that environment. To activate the environment, invoke the appropriate script. On Windows:

$ armi-venv\Scripts\activate.bat

Or on Linux:

$ source armi-venv/bin/activate

Note

You’ll have to activate the venv every time you open a new command line. Many people set up scripts to activate this automatically.

1.3. Getting the code

Clone the ARMI source code from the git repository with:

(armi-venv) $ git clone https://github.com/terrapower/armi

Tip

If you plan to contribute to ARMI (please do!), you may want to use SSH keys and use git clone git@github.com:terrapower/armi.git.

Now install the ARMI dependencies:

(armi-venv) $ python -m pip install -r requirements.txt

Then, install ARMI into your venv with:

(armi-venv) $ python setup.py install

Tip

If you don’t want to install ARMI into your venv, you will need to add the ARMI source location to your system’s PYTHONPATH environment variable so that Python will be able to find the code when you import it from other directories.

In Windows, click Start and type Edit Environmental Variable to adjust PYTHONPATH. In Linux, add export PYTHONPATH=/path/to/armi/source in a user profile script (like .bashrc).

To see if it worked, run the ARMI launcher script:

(armi-venv) $ armi

If it worked, you should see the (classic) ARMI splash screen and no errors:

 ---------------------------------------------------
|             _      ____     __  __    ___         |
|            / \    |  _ \   |  \/  |  |_ _|        |
|           / _ \   | |_) |  | |\/| |   | |         |
|          / ___ \  |  _ <   | |  | |   | |         |
|         /_/   \_\ |_| \_\  |_|  |_|  |___|        |
|         Advanced  Reactor  Modeling Interface     |
 ---------------------------------------------------

If it works, congrats! So far so good.