Author: Vincent Diepeveen
Date: 08:46:12 08/29/00
Go up one level in this thread
On August 29, 2000 at 11:33:23, Robert Hyatt wrote: >On August 29, 2000 at 10:19:38, Vincent Diepeveen wrote: > >>On August 28, 2000 at 22:21:40, Robert Hyatt wrote: >> >>>On August 28, 2000 at 19:32:05, Larry Griffiths wrote: >>> >>>>I have been reading about the History Heuristic and have seen pro's and con's >>>>about it. >>>> >>>>I plan on implementing it to see what happens. This heuristic is related to >>>>killer moves and uses the from and to squares in a 64 x 64 array to maintain >>>>history information when moves are bestmoves or cutoffs. Each entry has 2 to >>>>the depth power added to it when a bestmove or cutoff is found. >>>> >>>>Would you recommend the History Heuristic, and has anything changed for the >>>>better with the method described above? >>>> >>>>Thanks in advance. >>>> >>>>Larry. >>> >>> >>>Works fine, but don't use 2^depth... for reasonable search depths, that will >>>overflow 32 bit counters almost immediately. I use depth^2 which is much >>>safer... >>> >>>Other than that it works fine. If you don't get a cutoff by the time you have >>>tried a few history-ordered moves, you probably should give up and just search >>>the rest of the moves in random order. >> >>Oh well is this bob speaking? >> >>searching things in random order is never a good idea actually. > > >On nodes where you have to search _all_ moves, the order in which you search >them is 100% immaterial. These are the so-called ALL nodes. also called FULL >in Knuth/Moore's paper. The tree below this node is sure having a lot of cut nodes. The way in which you search this all node is sure making a big difference for those nodes. >So I don't follow. Once you are convinced that you can't find a fail-high move You never know this in advance. In crafty the chance is 5% that you get a fail high in DIEP it's 1%, still that's 1% chance to cheaply cutoff. >using normal means, random is just as good as anything else, since "anything >else" hasn't worked so far. And since random (generated order) is cheaper than >anything else, why not? Works for me. And others, I might add... So random clearly isn't smart.
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