Author: Pete Galati
Date: 21:46:39 09/04/99
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On September 04, 1999 at 23:39:41, James Swafford wrote: >On September 04, 1999 at 21:17:00, Pete Galati wrote: > >>On September 04, 1999 at 19:44:22, Ralf Elvsén wrote: >> >>>I was thinking of the number of positions one has to search >>>in the alpha-beta algoritm. With perfect moveordering the >>>number is roughly n^(d/2) , where n = number of moves >>>in a position and d = search depth. I know this is a >>>simplification of the actual formula but it catches >>>the "essence" of it. >>> >>>With the worst possible >>>moveordering it goes like n^d (same as mini-max). >>> >>>We can summarize this qualitatively as >>> >>>number of positions = n^(s*d) , where s = 1 for the worst case >>>and s = 0.5 for the best case. >>> >>>Is there anyone out there who has a feel for the actual >>>value of s in the programs used today? This would be a measure >>>of the quality of the moveordering. I realize that most >>>programs have a more complicated search structure with null moves, >>>hash tables etc, but it would be interesting to see >>>some educated guesses. >>> >>> Thanks in advance, Ralf >> >>Just a note since I don't know enough to discuss that, but Inmichess does seam >>to use a move order hashtable. It's the only program that I remember that in. >> >>Pete > > >I think lots of programs store moves in the hash tables. >I learned that trick from Crafty a couple years ago. > >-- >James Werner seams to have an extra hashtable in there other than hash & pawn hash, it's something that was rather fresh in my mind today because I was just adjusting the ini file to stop the paging with Inmichess. From his ini file: ;HASH real hashing, 12 Byte per entry (1048576 recommended) ;HASHSORT move order hash, 8 Byte per entry (2097152 recommended) ;HASHBAUER pawnhashing, 8 Byte per entry ( 65536 recommended) I have no idea why that's a separate hashtable BTW, thanks, I just now looked at some of your html from your page to get the email link for my page working. Believe it or not I've got a book about html but it's usually easier to look at an example that works. So that works now. Pete
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