Create or amend the documentation

You should draft documentation for any major new features that need explaining, or update the existing docs for any changes. The documentation lives in the docs folder alongside the code and changes should be included in your usual pull request to main.

You can view the docs locally in your browser. First, create and activate a Python virtual environment using your preferred tool, for example:

python3 -m venv .venv
source .venv/bin/activate

Then install the required Python packages from docs/requirements.txt:

pip install -r docs/requirements.txt

and then running

mkdocs serve

in the folder in which the index mkdocs.yml lives (the base folder).

It should say something like Serving on http://127.0.0.1:8000/, and you can then open this address in your browser to view the docs as they will appear online once you push them after editing.

Writing mathematical expressions

The docs support rendering of LaTeX math expressions using KaTeX via the pymdownx.arithmatex extension. Use standard LaTeX delimiters:

• Inline math: $...$, e.g. $\chi$ renders as \(\chi\)
• Display (block) math: $$...$$ on its own line, e.g.:

$$
H^2 = \frac{8 \pi G \rho}{3}
$$

Do not use the GitHub-style backtick syntax ($...$) as it will not render correctly with mkdocs.