===========================
Using environment variables
===========================

Some Python packages depend on environment variables for correct operation.

EXAMPLE: Theano requires that the directory containing the CUDA compiler is
included in the $PATH environment variable in order for GPU acceleration to be
enabled.

To change environment variables for all AEN applications, modify the project
runtime configuration file ``.projectrc``. For more information, see
:doc:`../basic-tasks/apps/use-crc`.

``.projectrc`` sets several AEN internal environment variables, sets up the
project environment and can set additional user environment variables for that
project. This file is sourced when a user opens any AEN application---including
Jupyter Notebook---and Jupyter kernels will be able to read the included
environment variables.
