Python Environment Management

SweepGen is designed to run in a virtual Python environment. By default, this environment is managed automatically by the waLBerla CMake system. Refer to Control the Managed Environment for information on controlling the base interpreter and installed packages in the managed environment. For advanced use cases and for development, Use an external Python Environment details how to set up SweepGen to use an external Python environment instead.

Control the Managed Environment

Setting the Base Interpreter

WaLBerla uses FindPython to locate the base Python interpreter. Refer to its documentation for ways to affect the discovery process.

Adding Additional Packages

To install additional packages into the SweepGen environment, first register them using the sweepgen_venv_require CMake function. This function can be invoked multiple times to add multiple requirements. The arguments to sweepgen_venv_require will be directly forwarded to pip install, so you can include any options pip install understands to affect the installation.

Calls to sweepgen_venv_require will only collect the set of requirements. To perform the installation, sweepgen_venv_populate must be called after all requirements are declared.

Example

#   First, list requirements
sweepgen_venv_require( pycowsay )  # Require a single package
sweepgen_venv_require( -r my-requirements.txt )  # Specify a requirements file

#   Then, populate the virtual environment
sweepgen_venv_populate()

Error

It is an error for your CMake system to call sweepgen_venv_require after sweepgen_venv_populate, or to call sweepgen_venv_populate more than once.

Use an external Python Environment

To forego SweepGen’s automatic environment manager, set WALBERLA_SWEEPGEN_MANAGED_VENV to OFF. Also, set Python_ROOT_DIR to point at the Python environment that should be used by SweepGen, e.g.:

cmake -S . -B build -DWALBERLA_SWEEPGEN_MANAGED_VENV=OFF -DPython_ROOT_DIR=<path-to-python-env>

You must make sure that the sweepgen package and its dependencies are installed in your environment, e.g. by running pip install -e ./sweepgen in the waLBerla project root.