Self-indexing (and traditional indexing) algorithms - Implementations and advice to share?

Question

As part of a research project I'm currently looking for open-source implementations of self-indexing algorithms, i.e. a compressed form of the traditional inverted index yielding nice characteristics such as faster lookup and/or less consumed space.

Do you know of any open-source implementations of self-indexing algorithms? Do you have other interesting takes on indexing algorithms or data structures to share?

All languages and license variants are welcome.

Answer 1

Here is a nice introductory presentation on self-indexing.