Isolated environments

Note

Isolated environments solve a couple of problems:

  • You can install specific, also older, versions into them.

  • You can create one for each project and no problem if the two projects require different versions.

  • You can remove the environment and create a new one, if not needed or with errors.

conda works as an isolated environment. Below we present the pip way!

Virtual environment - venv

Create a venv. First load the python version you want to base your virtual environment on:

module load python/3.6.0
python -m venv Example

“Example” is the name of the virtual environment. The directory “Example” is created in the present working directory.

If you want it in a certain place like “~/test/”:

python -m venv ~/test/Example

Activate it.

source <path/>Example/bin/activate

Note that your prompt is changing to start with (Example) to show that you are within an environment.

Install your packages with pip and the correct versions, like:

pip install numpy==1.13.1 matplotlib==2.2.2

Deactivate it.

deactivate

Everytime you need the tools available in the virtual environment you activate it as above.

source <path/>Example/bin/activate

More on virtual environment: https://docs.python.org/3/tutorial/venv.html

pyenv

This approach is more advanced and should be, in our opinion, used only if the above are not enough for the purpose. This approach allows you to install your own python version and much more…

Have a look on this manual https://www.uppmax.uu.se/support/user-guides/python-modules-guide/