Nix Installation

:term:`FiPy` now has a Nix expression for installing :term:`FiPy` using Nix. Nix is a powerful package manager for Linux and other Unix systems that makes package management reliable and reproducible. The recipe works on both Linux and Mac OS X.

Getting Started with Nix

There are a number of tutorials on getting started with Nix. The page that I used when getting started is on the Blog of the HPC team of GRICAD,

https://gricad.github.io/calcul/nix/tuto/2017/07/04/nix-tutorial.html

I also made my own notes,

https://github.com/wd15/nixes/blob/master/NIX-NOTES.md

which are a succinct steps that I use when setting up a new system with Nix.

Installing

Once you have a working Nix installation use:

$ nix-shell --pure

in the base :term:`FiPy` directory to install :term:`FiPy` with Python 2. To install with Python 3, use:

$ nix-shell --pure nix/py3.nix

nix-shell drops the user into a shell with a working version of :term:`FiPy`. To test your installation use:

$ nix-shell --pure --command "python setup.py test"

Note

:term:`Trilinos` is currently not available as part of the Nix :term:`FiPy` installation.

Additional Packages

To install additional packages available from Nixpkgs include them in the buildInputs list in nix/build.nix (in the nix subdirectory of the base :term:`FiPy` directory).

Using Pip

Packages unavailable from Nix can be installed using :term:`Pip`. In this case, the installation has been set up so that the Nix shell knows about a .local directory in the base :term:`FiPy` directory used by :term:`Pip` for installation. So, for example, to install the toolz package from within the Nix shell use:

$ pip install --user toolz

The .local directory will persist after the Nix shell has been closed.