Setup
=====

Just like Rat-vcpkg_ and Rat-Containers_, pyRat_
requires some setup in order to be built.

.. hint::

    :doc:`setup` and :doc:`build/index` section cover
    the build part of pyRat_ wheels but do not concern
    the installation of the wheel itself.

    If one already has a pyRat_ wheel available it does
    not require anything else than a compatible Python_ version:

    .. code-block:: bash

        python -m pip install ./pyrat-....whl

Prerequisites
-------------

In the end pyRat_ is yet another C++ project
built on top of the Rat C++ libraries.

**Building it thus requires the same tools
used to build Rat in the first place:**

- Compilation toolchain
- Dependencies
- Header files
- ...

.. seealso::

    - Setup for Rat-vcpkg_: :doc:`../repo-rat-vcpkg/setup`
    - Setup for Rat-Containers_: :doc:`../repo-rat-containers/setup`

pyRat_ links with Rat-Models_ (which transitively
links with all other Rat libraries and their
dependencies) thus requiring the same tooling.

`Python wheels`_ can then be built using the same environment.

Install UV_
-----------

.. note::

    If using Rat-Containers_: ``rocky-cuda-pyrat`` already ships with UV_.

In addition to the prerequisites one
will need Python_ tooling for pyRat_.

UV_ is required to easily manage different
Python_ versions and build multiple wheels.

.. important::
    
    Since pyRat_ ships C++ compiled code it is strongly coupled
    to Python_'s C++ ABI which changes with each minor version.

    This means that pyRat_ wheels compiled with Python_ ``v3.12.x``
    will only work with Python_ ``v3.12.x`` and no other versions.

    UV_ allows to easily switch Python_ versions
    allowing for broader Python_ coverage.

.. Links
.. _Project-Rat: https://gitlab.com/project-rat
.. _pybind11: https://github.com/pybind/pybind11
.. _pyRat: https://gitlab.com/project-rat-extras/pyrat
.. _Python: https://www.python.org/
.. _Python wheels: https://pythonwheels.com/
.. _Rat-Containers: https://gitlab.com/project-rat-extras/rat-containers
.. _Rat-Models: https://gitlab.com/project-rat/rat-models
.. _Rat-vcpkg: https://gitlab.com/project-rat-extras/rat-vcpkg
.. _UV: https://github.com/astral-sh/uv