Author: Peter Kappler
Date: 23:58:29 10/05/99
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On October 05, 1999 at 22:10:32, Robert Hyatt wrote: >On October 05, 1999 at 21:04:40, Peter Kappler wrote: > >>On October 05, 1999 at 16:36:59, William Bryant wrote: >> >>>When updating the history for a move that has generated a cutoff, >>>what value to people use. >>> >>>Do you use ply or some function of ply which means that the closer you are to >>>the leaves, the greater the value being used for updating? >>>ie: History[from][to] += ply; >>> >>>Do you use depth or some function of depth which means the closer you are to the >>>root, the greater the value being used for updating? >>>ie: History[from][to] += ply; >>> >>>Or are there other values being used. >>> >>>Thank you in advance. >>> >>>William >>>wbryant@ix.netcom.com >> >> >>Hi William, >> >>I think moves that cause a cutoff near the root should get a higher bonus, as >>they have been searched more deeply. In Grok, I increment the history score by >>2^depth, which greatly favors moves that cause cutoffs near the root. I think I >>got the exponential scoring idea from an ICCA article, but I can't recall the >>author. >> >>--Pete > > >That is the right value from the JICCA article, but think about what happens to >that number when depth = 20 and beyond, which I see in endgames all the time, >even at blitz time controls. your 32 bit counter overflows quickly... This is a good point, though I'm sure it's a much bigger problem for Crafty than Grok. :-) I might try your depth*depth idea. Thanks for the tip. --Peter
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