Author: Cristian Zaslo
Date: 01:31:02 03/17/99
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On March 16, 1999 at 22:55:09, Robert Hyatt wrote: >On March 16, 1999 at 18:36:08, Peter Kasinski wrote: > >>On March 16, 1999 at 16:58:09, Robert Hyatt wrote: >> >>>On March 16, 1999 at 12:04:51, Dann Corbit wrote: >>> >>>>On March 16, 1999 at 02:50:20, Cristian Zaslo wrote: >>>> >>>>>Hi everybody ! >>>>>Will anyone be so kind and briefly explain me what sort of >>>>>advantages would (not) have a chess programmer to implement >>>>>a SEE in his code. >>>>>Much obliged to you, >>>>>Cristian >>>>Er.... >>>>What's a SEE? I've been programming 33 years and I have never heard of one. >>> >>> >>>Stands for "Static Exchange Evaluator". It is a procedure that analyzes all >>>captures on a single square and returns a value indicating who comes out >>>ahead. >>> >> >>>It can be used to order captures so that you try QxP where the pawn is free, >>>before you try QxR where the R is defended. It can also be used to discard >>>some captures in the q-search such as QxR where the R is defended and you are >>>guaranteed to lose material. >>> >>>Used correctly it is possible to cut the size of the tree being searched by >>>50% or more. >> >> >>Bob, I looked at Swap() in Crafty where this is implemented. >>Not using bitmaps I don't have a cheap way to determine what pieces attack a >>given square. Would it still be profitable for me to compute these attacks in >>order to use SEE? >> >>thank you, >>PK > >There are far more non-bitboard programs than bitboard programs. And SEE >works just fine. It will cost a little more probably, because there are >loops that don't exist in bitmaps, but I had such a function in Cray Blitz. > >The idea is to take the target square, and first find out what pawns are >attacking the square, then bishops, knights, rooks, queens and finally >kings. Then the 'minimax' code at the bottom of my Swap() can be taken >directly... So, am I right saying that SEE may be used to improve move ordering in the Q-Search but it cannot be used as a single way to determine whether a leaf node is or not a quiet one ? Thanks!
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