Author: Vincent Diepeveen
Date: 21:19:22 12/19/05
Go up one level in this thread
On December 16, 2005 at 03:32:16, Vasik Rajlich wrote: >On December 16, 2005 at 00:56:04, Zappa wrote: > >>On December 15, 2005 at 17:05:00, Sergei S. Markoff wrote: >> >>>1) Fruit. >>> >>>Fruit search seems to be primitive. "History pruning" is a variation of >>>well-known idea. After implementing such method in SmarThink some years ago I >>>named it "history-based pruning" and then changed to "ordering-based pruning". >>>The outcome of such methods very depends of whole search model, but anyway >>>history pruning is not the key to Fruit strength. >>> >>>To my mind, the key of Fruit strength is that the "Chess is the art of >>>exchange". So, Fabien's idea about flexible game stages looks to be a beautiful >>>way to improve positional play. Fruit can effectively consolidate the position. >>>It simply knows when to excange to improve position. I think that it's the main >>>key (cumulative with very good tuning of evaluation function). I think Fruit is >>>very perspective. The main line of progress for this project, to my mind, is to >>>add more complicated knowledge and intellectualize a search. >>> >>>2) Rybka >>> >>>Some time ago we discussed with Gian-Carlo Pascutto an idea of create special >>>"SET-tables" with sets of piece-square values indexed by 1) material on the >>>board; 2) king position; 3) pawn structure. Such tables can be calculated by >>>analyzing a lot of games. That time I delayed my work in this area because I >>>found other perspective things. >>>You can see that Rybka executable contains a lot of precalculated tables. And >>>also we all know that Rybka plays positional style. My version is that Rybka >>>uses some variation of SET-approach. At all cases it uses some precalculated >>>positional knowledge, but what sort of it? ;) >> >>My personal opinion: >> >>Fruit wins by 3 things: deep PV checking, mobility, and correctness. I talked >>about this with Fabien at Reykjavik. When you have mobility, you are very >>sensitive to being "driven back". And when you can check your mainline 18-20 >>ply and not lose any mobility, its very probably you're playing a good move. >> >>Rybka: I'm starting to think that a lot of Rybka's strength is tactical. Try >>that baby out on a few test positions some time. For example, the rapid TC CEGT >>list has Rybka 55 rating points ahead of Fruit, while the slower BFF list has >>Rybka only 15 rating points ahead of Fruit. >> >>anthony > >We need more data. I'll try to put it together when it's all ready. > >One thing people tell me is that Rybka tends to stick with her moves from lower >depths more than other engines. This would also suggest better blitz play. > >Vas In past programs sticking to the same move and showing same mainline was very common. We called it back then preprocessors. Vincent
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