GNU Backgammon (@gnubg{}) plays and analyses backgammon games and matches.
FIXME update this section (latest version is on web page).
It is currently a work-in-progress. So far it is able to play cubeless games and tournament matches, evaluate and roll out positions, tune its own evaluation functions using either TD or supervised training, maintain databases of positions for training and other purposes, and more.
It is driven by a command-line interface, and displays an ASCII rendition of a board on text-only terminals, but also allows the user to play games and manipulate positions with an X11 board window where available.
Plans for the future include completing its ability to play and analyse cubeful games and matches, and making it extensible on platforms where Guile is available, so that the user can program it to answer sophisticated questions like "How many chequers must Black have borne off in positions like this one to be able to accept a double?" and automate complicated rollout tasks.
It currently plays at about the level of a strong intermediate flight tournament player (rated in the mid 1700s on FIBS, the First Internet Backgammon Server -- around the 90th percentile) and is gradually improving; it should be somewhat stronger than this when released. Since almost all of the CPU time required during supervised training is spent performing rollouts, and rollouts can easily be performed in parallel, it is hoped that users will be able to pool rollout results and collectively train it to a level stronger than any individual could obtain.
If you can tolerate the rough edges, periodic snapshots of @gnubg{} and anonymous CVS access to the pre-release source are being made available. You can also compete against recent versions of @gnubg{} on FIBS; it plays there under the names `gnu' and `mgnutest'.