Author: Robert Hyatt
Date: 07:47:42 01/14/02
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On January 13, 2002 at 10:17:38, David Rasmussen wrote: >On January 12, 2002 at 20:37:36, Robert Hyatt wrote: > >>On January 12, 2002 at 10:07:11, Pham Minh Tri wrote: >> >>>main.c: "Deep Blue extension limit removed and restored to one ply of extension >>>per ply of search." >>> >>>Amazing! I still think that Crafty 18.12 is significantly stronger than previous >>>versions because of that limit. >> >> >>I did a lot of testing and found that in real games, the DB method simply >>does too many extensions for my liking. The normal Crafty search can explode >>in some positions. It happened more often with the DB limit (no more than >>two plies of extension for any two consecutive plies, rather than the current >>one ply of extension max for any ply.) > >How about a general limit saying if we're at ply 7, and we have extended 4.25 so >far, it is ok at this ply to extend as much as 2.75, since this will amount to 1 >per ply on average anyway. I realize that this would yield even more extensions >than with the deep blue method, but if it could be restrained correctly, I think >it would also be tactically stronger. I will try it for sure. > >/David I suppose the "ultimate" would be to say "I am at ply=X, so I can't allow more than "X" extensions (total) at any point in the tree up to ply=X. However, I think that would likely explode badly. I think that extensions are "connected" so that parts of the tree get none, and some parts extend like mad due to exposed kings and so forth. I really don't want to extend parts of the tree where nothing serious is going on... Will be interesting to see how your test goes... The "ultimate" example I gave is probably too far out in left field. And in fact, I didn't even like the "two extensions max per two consecutive plies" idea. But you might find a way to make it work better than I did..
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