# Installation¶

DIJITSO is normally installed as part of an installation of FEniCS. If you are using DIJITSO as part of the FEniCS software suite, it is recommended that you follow the installation instructions for FEniCS.

To install DIJITSO itself, read on below for a list of requirements and installation instructions.

## Requirements and dependencies¶

DIJITSO requires Python version 2.7 or later and depends on the following Python packages:

• NumPy

These packages will be automatically installed as part of the installation of DIJITSO, if not already present on your system.

Additionally, to run tests the following packages are needed

• pytest
• mpi4py (for running tests with mpi)

## Installation instructions¶

To install DIJITSO, download the source code from the DIJITSO Bitbucket repository, and run the following command:

pip install .


To install to a specific location, add the --prefix flag to the installation command:

pip install --prefix=<some directory> .


## Environment¶

Instant’s behaviour depened on following environment variables:

• DIJITSO_CACHE_DIR

This option overrides the placement of the cache directory. By default the cache directory is placed in .cache/dijitso either below the home directory or below the prefix of the currently active virtualenv or conda environment if any.

• DIJITSO_SYSTEM_CALL_METHOD

Choose method for calling external programs (c++ compiler). Available values:

• SUBPROCESS

Uses pipes. OFED-fork safe on Python 3. Default.

• OS_SYSTEM

Uses temporary files. Probably OFED-fork safe.

Warning

OFED-fork safe system call method might be required to avoid crashes on OFED-based (InfiniBand) clusters!