First public alpha: 0.4
FastRank
FastRank is an implementation of CoordinateAscent[1] from Ranklib that you can pip install; written in Rust and uses threads for efficiency; it will scale much better than the Java version to large datasets and many features.
It also has RandomForests, and someday LambdaMART (others depending on interest). I've been thinking a lot about what the limits of coordinate ascent are (linearity), and will probably play with that in future versions.
This is ready for production use in the sense that I used it for my TREC submission this year. The python API could use some thoughts and experiences (post issues on Github).
pip install fastrank[1] Metzler, D., & Croft, W. B. (2007). Linear feature-based models for information retrieval. Information Retrieval, 10(3), 257-274.