Python environment

In OGS we make use of Python packages at different stages, e.g.:

• TESPy for simulating thermal engineering plants in a benchmark
• pytest for testing Python functionality in OGS
• nbconvert for testing Jupyter Notebooks
• …

Python packages are usually installed via pip inside an isolated environment (a virtual environment). We use a modern alternative to pip: uv .

Recommendation: Use the OGS_USE_PIP=ON CMake option when configuring OGS

Make sure that you installed the uv -tool.

When configuring OGS with OGS_USE_PIP=ON uv creates a new virtual environment in the .venv-directory inside your build directory. It will also install required Python packages into this environment. For example, OGSTools or Jupyter will this way be available ready-made in a consistent configuration.

Example usage:

cmake --preset release -DOGS_USE_PIP=ON

When you want to use the python packages in this virtual environment, you need to activate it by running

cd ../build/release          # the build directory
source .envrc                # Linux, Mac OR
Invoke-Expression .envrc.ps1 # Windows (PowerShell)

where .envrc is a script including source .venv/bin/activate for activating the virtual environment as well as setting some paths. If you have the direnv -tool installed and set up the virtual environment will be activated automatically upon changing into the build directory.

To manually add Python packages run the following inside your build-directory:

uv pip install python-package-name

Pip & Benchmarks

You can use the argument PYTHON_PACKAGES on AddTest() to specify additional Python package dependencies.

The following example would install the latest version of numpy and pandas version 0.1.2:

AddTest(
    ...
    PYTHON_PACKAGES numpy pandas==0.1.2
    ...
)