Author: Slater Wold
Date: 11:32:58 01/06/04
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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. SE and nullmove do not mix. And that's straight from Hsu. From speaking with him (via e-mail), I gathered that this would be his approach using nullmove, and I tried it in Crafty with very nominal success: 1. Search to a specified depth; I used 10 because in Crafty you could get there fairly quickly and the score/pv were usually fairly stable. 2. Does the best move beat the 2nd best move by at least 40%? 2a. YES! -> Go to 3. 2b. NO! -> Search to the next depth normally, and return to 2. 3. Turn off nullmove. Extend. (I didn't do a full ply extentsion here, but you can test it and see what's best for you.) 4. Is this move 50% better than the 2nd best? 4a. YES! -> Go to 5. (This move truly is 'singular'.) 4b. NO! -> Search to the next depth normally, and return to 2. 5. Extend at least a full ply, with nullmove, then return to 4.
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