Author: Robert Hyatt
Date: 19:52:41 01/06/04
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On January 05, 2004 at 19:48:25, Bas Hamstra wrote: >>>Here is what I tried (idea from Bruce I believe): >>> >>>Before you search all moves (after nullmove) you search all moves (unsorted) >>>with D-R >> >> Good point I had missed :) >> I was doing an expensive D search with (Alpha-Margin,Alpha-Margin+1) and if >>only one move failed high, search it again with (Alpha,Beta) extended 1 ply. >> >>>and check if there is one and only one move with a score above alpha >>>*and* above Alpha-Margin. >> >> So if I get it right, you search all moves with D-R and a null window around >>Alpha-Margin. If only one move fails high, then search it again with D-R and a >>null window around Alpha. If it fails high again, then that move is extended. > >It did not do this, but your idea might be better. I did one single pass with >window(Alpha-M, Alpha) and simply counted the results. I did it the classic "cheap" way which is what I think Bruce did. IE I hoped that one move failed high, and that all the rest failed low on a lowered search window. If a second failed high, I gave up. I did once try to do the "right" solution, that of seeing if one of the two fail high moves was significantly better than the other, but that did not seem to help at all and just made the tree somewhat cheaper. This is why I always called this the "cheapo singular extension" approach. It is cheaper than Hsu's algorithm, but also signficantly less accurate. > >> Thanks for the tips. I'll report my results if I manage to make it work. > >Please do, I am interested. > > >Bas.
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