Author: Robert Hyatt
Date: 06:38:16 01/26/01
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On January 26, 2001 at 05:32:26, Steffen Jakob wrote: >On January 25, 2001 at 14:11:36, Peter McKenzie wrote: > >>On January 25, 2001 at 08:20:26, David Rasmussen wrote: >> >>>Howdy. >>> >>>Inspired by the thread on extensions, I was wondering whether the idea of >>>negative extensions or reductions could be a good one. >>> >>>I mean, maybe many of the "unsound" pruning methods would be sounder if, instead >>>of just pruning, they just adjusted the resulting depth down. In that way, a >>>line would still be examined, only later. >> >>Hi, in the past I have thought of negative extensions too although I haven't >>tried implementing them yet. I wouldn't consider nullmove to be a negative >>extension, its not really in the spirit of an extension - I'd just call it a >>pruning method. >> >>In my mind, extensions are usually a move based thing. By this I mean that we >>can see some property of the move we have just played (or are just about to >>play, depending on exactly how you implement the extension) which indicates that >>we should extend. Obvious examples are >>- check extension >>- recapture extension >>- single response extension >>- passed pawn push extension >> >>So the question is, what sort of moves could be candidates for a negative >>extension? > >Some underpromotions. > >Greetings, >Steffen. captures that SEE say lose massive material last few moves at a ply when the score has not changed from alpha for all the others. Move that the hash table says would fail low if the hash table entry had enough draft to make this happen. moves that return a piece to the square it sat on 2 plies ago. lots of things to try. Whether they would work or not is another thing, of course. :)
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