Author: Martin Giepmans
Date: 11:12:58 01/11/02
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On January 11, 2002 at 12:28:56, José Carlos wrote: >On January 11, 2002 at 12:10:32, Martin Giepmans wrote: > >>On January 11, 2002 at 11:44:39, David Rasmussen wrote: >> >>>[D]2Q2n2/2R4p/1p1qpp1k/8/3P3P/3B2P1/5PK1/r7 w - - 0 1 >>> >>>In the above position, my search tree explodes because of extensions. It takes > >>>3 minutes and 42 million nodes to finish an 8 ply search. How does your program >>>do? >>> >>>Any good ideas on how to limit extensions in such a position. >>> >>>P.S. Solving the position is no problem. It is a simple mate in 5 plies, and is >>>found very early on at depth 1 or 2 or so. Still, there must be something >>>unsound about my extensions, or at least room for improvement, when this >>>position makes the tree explode. >>> >>>/David >> >>I don't know if I understand your question. >>How can you reach depth 8 when a mate is found at depth 1 or 2? >>Doesn't your engine stop in such a case? >>Even if you want to look for a shorter mate, searching *deeper* is of course >>useless ... > > That's wrong. You can find a mate in 5 at depth 2, but you can't be sure there >isn't a shorter mate until you finish ply 9, supposed you don't do some risky >prunning. If you do null move, for example, you may need to search beyond that >to find a shorter mate. > > José C. > Ah, what i meant was: searching deeper than the length of the mate-pv. In this case the pv is 5 ply, so depth 8 is way too much. Martin >>Anyway, if the search explodes after a mate is found, I guess there must also be >>something wrong with the hashtable. >> >>Martin
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