Author: Robert Hyatt
Date: 22:06:54 05/16/05
Go up one level in this thread
On May 16, 2005 at 12:01:19, Matthew Hull wrote: >On May 16, 2005 at 11:27:29, Robert Hyatt wrote: > >>On May 15, 2005 at 15:53:11, Matthew Hull wrote: >> >>>On May 15, 2005 at 11:02:17, Robert Hyatt wrote: >>> >>>>On May 15, 2005 at 01:53:40, Joshua Haglund wrote: >>>> >>>>>On May 14, 2005 at 10:40:22, Robert Hyatt wrote: >>>>> >>>>>>On May 14, 2005 at 01:06:41, Joshua Haglund wrote: >>>>>> >>>>>>>On May 13, 2005 at 22:48:44, Robert Hyatt wrote: >>>>>>> >>>>>>>>On May 13, 2005 at 19:21:37, Joshua Haglund wrote: >>>>>>>> >>>>>>>>>On May 13, 2005 at 13:48:27, Pablo Ignacio Restrepo wrote: >>>>>>>>> >>>>>>>>>>Hello Robert >>>>>>>>>>It was a mistake in redaction. Antiajedrez or Antichess have been my extreme >>>>>>>>>>anticomputer style, across I have won many times many top engines in all time >>>>>>>>>>game control. But usually Crafty have been for me a real problem for beat, iqual >>>>>>>>>>than Rufian, Tiger Gambit 2.0 , Quark ..... >>>>>>>>>>Usually I am playing into playchess. There I have won many top engines, but to >>>>>>>>>>repeat..... Craftuy have ben very strong, but today in morning look ...... 2 >>>>>>>>>>easy draw. Why? >>>>>>>>>>Regard, >>>>>>>>>>Pablo >>>>>>>>> >>>>>>>>> >>>>>>>>>Hello Pablo, >>>>>>>>> >>>>>>>>>I've told you a couple times, if you remember, Dr. Hyatt removed the stone-wall >>>>>>>>>detection code in version 19.15. It was removed because it appeared to Dr. Hyatt >>>>>>>>>it wasn't needed anymore. >>>>>>>>> >>>>>>>>>As a result it should be easier for you using "anti-chess" playing Crafty. >>>>>>>>> >>>>>>>>>Joshua Haglund >>>>>>>>>toneewa@yahoo.com >>>>>>>> >>>>>>>> >>>>>>>>If I looked at the game correctly, this wasn't a stonewall type problem, it was >>>>>>>>just e4 Nf3 and Bc4 for white if I am recalling the right game (I have looked at >>>>>>>>several today so that could be wrong). >>>>>>> >>>>>>>[D]k1/2rbp1pp/1p3p1r/p2P1P2/P1P1B1P1/1P2R2P/5NK1 b - - 0 121 >>>>>>>[D]n3/2rr1q1k/1p1p1p1p/p1p1pPpP/4P2N/P1PP2Q1/1P3PRK/6R1 b - - 0 38 >>>>>>> >>>>>>>These are to me "stone-wall" positions. I don't know how Crafty use to detect >>>>>>>the "stone wall"... by pawn formation positions or by recognition of particular >>>>>>>moves; maybe both. Pablo use to play Crafty and have not much luck before the >>>>>>>removal of the "stone-wall" detection. >>>>>>> >>>>>>>Joshua Haglund >>>>>>>toneewa@yahoo.com >>>>>> >>>>>> >>>>>>The stonewall code looked for pawns at f4, e3, d4, c3. If three of those were >>>>>>present, it assumed "stonewall"... This doesn't seem to match... >>>>> >>>>> >>>>>What if the pawns are for black?? >>>>>In these examples of Pablo's games; >>>>> >>>>>black pawns: a5,b6,c5,d6,e5,f6,g5,h6 >>>>>definately stone wall with black. >>>>> >>>>>white pawns: a4,b3,c4,d5,f5,g4,h3 >>>>>partial wall, but two strong pawn chains. >>>>> >>>>>The code was removed (19.15) so Crafty doesn't recognize anything like that now? >>>>> >>>>>Joshua Haglund >>>>>toneewa@yahoo.com >>>> >>>> >>>>Wouldn't matter. The "pattern" is a pawn at c3, d4, e3 and f4, or if you mirror >>>>that for black, c6, d5, e6, f5. The "stonewall problem" is the pawn at e3/e6 >>>>makes it very difficult for the bishop it is blocking. And the bishop tangles >>>>other pieces up making a quick g/h file attack successful if the engine makes a >>>>single mistake in untangling. >>>> >>>>If you have played e4/e5, then that problem doesn't happen, since d3/d6 lets the >>>>bishop out. >>> >>> >>>>To handle the case in the game(s) given, crafty depends on its >>>>"blocked pawn" code to avoid the position getting so blocked and becoming >>>>drawish. >>> >>> >>>But is that logic only active if crafty knows it's playing human? >> >> >>That's a good question. I'll go back a few versions and look. I don't think it >>was "human only" however, but it might have been. >> >>Just looked at 19.6, and it was active for all opponents, not just humans. The >>only way it was turned off was to turn off the asymmetric evaluation option, >>which also turned the stonewall detection code off since it was asymmetric as >>well. > > >I'm probably thinking of the old internal GM and "blockers" lists, which used to >take special care to prevent closed positions, IIRC. Yes "blockers" would just ramp up the blocked pawn penalties by increasing the asymmetry. Made it _very_ difficult to block things up, but did open up another "hole" that a very strong player might exploit, in that it would try too hard to avoid blocking things, even when it should.
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