Author: Pete Galati
Date: 18:17:00 09/04/99
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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
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