Fabien Letouzey wrote:It's not like this command [searchmoves] has to be activated or not. It's just not needed for normal game play (e.g. engine matches).
I can see some potential use for book learning or "2nd best move" analysis, but many (if not most) engines and probably most GUIs as well don't use this command at all (guess).
Exatly, Fabien. I think, it is very useful for some analysis. It is very easy to implement in the engine (much easier than an efficient multi-PV mode) and can serve as a "poor man's multi PV mode". In Shredder Classic, if I want to know, if there is a good alternative to the move shown by the engine, I press shift and input the move with the mouse, and a search will be started with that move excluded.
BTW. Other than multi-PV mode, which an engine does not need to support, according to the UCI protocol, every engine must support searchmoves. I think, it better would have been a voluntary engine feature. In practice, engines will work well, without this feature. Shredder Classic uses it for analysis. When the game move and the engine move differ, Shredder will start the same search to fixed depth (the same depth that was reached before) with only the game move inside search moves. This should give the best comparision of the two scores. Depending on the score difference and analysis options, an annotation will be written to the game score. I personally think, this is better, than the alternative of doing the game move, and starting a fixed depth search of depth-1, because (for example) search extensions may differ. Of course, it might differ a bit anyway (although not for my engine, I think).
To the original question: I had asked Martin Blume, and he said, searchmoves is not supported in Arena. It seemed not high on his list. But this was some time ago - certainly over a year.
Cheers,
Dieter
Posted: 30 Apr 2005, 00:30