Author: Uri Blass
Date: 09:14:18 05/11/03
Go up one level in this thread
On May 11, 2003 at 10:21:12, Omid David Tabibi wrote: >On May 11, 2003 at 07:19:04, Tim Foden wrote: > >>On May 10, 2003 at 21:23:00, Omid David Tabibi wrote: >> >>>On May 10, 2003 at 20:32:10, Matthias Gemuh wrote: >>> >>>>On May 10, 2003 at 17:49:01, Mike Siler wrote: >>>> >>>>>When Sjeng finishes a search, it displays among its stats a move ordering >>>>>percentage. Does anyone know how this is calculate? >>>>> >>>>>Michael >>>> >>>> >>>>In most programs, it is the ratio FailHigh_on_fist_move/All_FailHighs. >>>> >>> >>>Why not use a more general figure: >>>ratio of "first move being the best" / "all (interior) nodes" ? >> >>I think this is because there are generally 2 types of interior nodes... one's >>that do fail-high, and ones that don't fail-high. >> >>In the ones that fail-high, we are very interested on the fail-high happening on >>the first move. >> >>In the ones that don't fail-high, we generally fail-low (due to alpha+1=beta), >>we don't (in general) have a best move. And it will make hardly any difference >>what order we search the moves in, as we will have to look at them all anyway. >> > >That's true, but my point is that we shouldn't confine the figure only to >fail-high cases, but also consider other nodes which produce a best move. >Anyway, the total figure will not vary significantly. I do not understand how do you know if a move is the best during a normal search. Some facts: 1)If the first move fail high it does not mean that it is the best move and the program only knows about a move that is good enough to refute the opponent move and does not search for the best move that does it. 2)If all the moves fail low you cannot know which one of them was the best without special search. Uri
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