Book learning in Polyglot / Winboard

[lantonov]

Just liked to ask what is the situation with book learning in Polyglot / Winboard. Polyglot has such an option, but its manual says it is noop. On the other hand, hgm.nubati has a whole branch of Polyglot with learning ability, so that this feature does not seem dead at all. What are the intentions of the developers ? Something like in Crafty ? (http://chessprogramming.wikispaces.com/Book+Learning)
Is this feature usable at the moment and how ?

[H.G.Muller]

Book learning in Polyglot means it keeps track of the number of games and points scored with each book move in the 'learn' fields of the book Polyglot handles. (So NOT the XBoard GUI book!) And then uses this information to modify the chance of picking the move compared to the book weights. (Moves that have hardly been played get extra probability to promote diversity; moves that have been played a lot and perform significantly worse than others get their probability reduced.)

WinBoard knows nothing about all this; according to WinBoard Polyglot is just an engine, and is free to handle its private book in any way it likes. When you would use the book later as GUI book in WinBoard, it would not be affected by the learning, as WinBoard ignores the learn fields of a Polyglot book. (You can edit them, though, with the Edit Book command.)

[Edit] I fixed this in the manual now. I did not even know Polyglot did have a manual; I just see it as a back-end of WinBoard...

[lantonov]

Thanks, HGM. If you intend to work further on it, just a couple of suggestions:

1. Should be able to remove bad moves or decrease their weights or both (with a minus score / lost games less than some threshold). This would be useful because books as created with Polyglot are on the basis of a large number of games and the problem is more to weed out bad moves than to add good moves.

2. To work on the Winboard / Xboard GUI book rather than on a Polyglot-specific book. In tournaments, chess servers, etc. we use the GUI book with different engines, so the learning is more important in the GUI. If needs be, move the relevant code from Polyglot to the GUI.

[H.G.Muller]

The learning is supposed to be engine-specific. So it would be a bad idea to use it on the GUI book, which is used by all engines. The GUI book is really intended for providing game diversity in tournaments, not so much to improve the winning chances of the engines that use it.

For editing the book and tuning the book weights, XBoard/WinBoard is an excellent tool.

[lantonov]

The learning is supposed to be engine-specific.

You are formally right but, practically, this decreases the utility of the book functions.