Author: Robert Hyatt
Date: 20:28:19 01/06/04
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On January 06, 2004 at 10:48:11, Zach Wegner wrote: >On January 05, 2004 at 08:48:23, José Carlos wrote: > >> Hi, I'd like to try singular extensions in my program. I've been trying to >>think about it and all my tries so far result in worse performance. After some >>web search I haven't been able to find anything but the general idea described. >> Is there any good description somewhere? Some pseudo-code? I guess there must >>be something interesting in the archives but I can't download all of them. >> Thanks in advance, >> >> José C. > >The way Hsu described it was along the PV, you search all moves like normal, and >you have two values containing the best and second best scores, and after all >moves are searched, if the best score is more than the second by a certain >margin, then research the best move with a deeper depth. That's not quite accurate. You search the first move at a PV node normally, and then you search the remainder of the moves at that node with an offset (lower) window. If all fail low, the first move is singular. You re-search with depth+1. If a second fails high, you simply figure out if one is better than the other by the singular margin by a single re-search. That is PV- singular. He also defined "fail-high" singular, which is a SE that is triggered at a node where a single move will normally fail high, and you verify that all the rest fail low on the same offset window. I can explain further if you want. > >Regards, >Zach
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