Author: Eugene Nalimov
Date: 22:40:15 02/11/99
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On February 12, 1999 at 00:21:08, Eugene Nalimov wrote: >On February 11, 1999 at 23:36:09, Bruce Moreland wrote: > >> >>On February 11, 1999 at 16:21:06, Will Singleton wrote: >> >>> >>>On February 11, 1999 at 12:52:27, Bruce Moreland wrote: >>> >>>> >>>>On February 11, 1999 at 08:23:10, Peter Fendrich wrote: >>>> >>>>>Can't check that from here, but it "must be": >>>>>"Null Move and Deep Search: Selective-Search Heuristics for Obtuse Chess >>>>>Programs." Donninger, C. (1993). >>>>>ICCA Journal, Vol. 16, No. 3, pp. 137-143. (A) >>>>> >>>>>I tried it but it was no hit. >>>>>That doesn't mean that it couldn't work for other programmers in other >>>>>programs... >>>> >>>>I expect that Ernst will respond, because he refined it and I think still uses >>>>it. >>>> >>>>bruce >>> >>> >>>I tried it (only allowing null-move when material imbalance exists) and found >>>very little change. >>> >>>Regarding your thought about threat-detection and null-move, a reading of >>>Anantharaman's article (ICCAJ 1991) indicates that he found little or no benefit >>>to this. But I remember something about you detecting mate threats with null >>>move. Is that right? >> >>That seems to help on some tactical tests. Sometimes I return mate scores that >>are outside the window, and when I find one of these I extend all of the >>candidates. >> >>So, in this case, if you let your opponent move when it is your move, and as a >>result you are instantly mated, extend everything a little, since you might end >>up pushing the mate over the threshold. >> >>The null-move killer position is WAC 141. It's an obvious mate that humans can >>see easily, and some programs can see really quickly, but a generic null-move >>program can't see it very well. >> >>4r1k1/p1qr1p2/2pb1Bp1/1p5p/3P1n1R/1B3P2/PP3PK1/2Q4R w - - 0 1 >> >>The key is Qxf4, and it's a forced mate. >> >>bruce > >According to Murray Campbell's lecture that he gave last year at MS, >DB team againg beleived in singular extensions (I wrote about the >lecture at r.g.c.c., maybe there were more details, I cannot >remember now). > >Eugene Sorry, I think that now I remember Anantharamans' threat extension, and it differs from singular extension... But that extension is static - he just calculated # of squares near the king that are controlled by opponent. Bruce writes about dynamic threats detection, it must be more powerful. Eugeen
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