Annoy Index Architecture (Inheritance Diagrams)

This page shows the class inheritance structure for the Annoy backend and the high-level Index facade, using Sphinx’s built-in inheritance diagram support (the same approach used in Matplotlib’s docs).

Note

Enable the extension and ensure Graphviz is available:

extensions += ["sphinx.ext.inheritance_diagram"]

The directive renders via Graphviz (dot). Install Graphviz in your build environment if it is missing.

Index + backend + mixins (public view)

Reading this diagram

• Annoy is the low-level C-extension backend and owns the actual index state and core operations.

• Index is the Python facade that subclasses the backend and composes behavior using independent mixins.

Mixins only (independence + MRO scan)

This diagram focuses only on the mixins so you can quickly confirm there is no unexpected inheritance between mixins (they should be independent).

Notes and limitations

Inheritance diagrams show class derivation, but they do not show composition relationships (e.g., an optional self._annoy backend attribute). For composition support, refer to the “glue” helpers documented elsewhere (e.g., backend_for(self), lock_for(self)).

See Also

• sphinx.ext.inheritance_diagram

• Graphviz (dot) documentation