Author: Miguel A. Ballicora
Date: 14:30:46 08/28/01
Go up one level in this thread
On August 28, 2001 at 17:01:08, Uri Blass wrote: >On August 28, 2001 at 16:56:54, Uri Blass wrote: > >>On August 28, 2001 at 15:34:30, Peter Berger wrote: >> >>>On August 28, 2001 at 11:58:02, Dieter Buerssner wrote: >>> >>>> >>>>However, I don't totally agree, that this is a King safety problem. For many >>>>depths, Kd6 and Ke8 have almost the same score (or have the same score). Sure, >>>>fiddling a little bit at KS-values will make Yace "find" the correct move >>>>muchearlier. I actually lowered some time ago some "K-advance-penalty". But I >>>>had the feeling, that this makes Yace weaker after some time, so I put back the >>>>old values. >>>> >>>>Also, this position may be a bit unusual, and not fitting some heuristics used >>>>in many chess programs. Usually programs come out of book, in castled position, >>>>or with a closed center. Neither is the case here. >>>> >>>>BTW. An material only eval, never switches away from Kd6. >>> >>>I agree and never said anything else. You won't want your engine to play Ke8 >>>here though and lose in about 5 moves if it can be avoided - it definitely is a >>>king safety problem ( why else would the engine prefer Ke8 anyway ? ) It is an >>>exception of the usual rule >> >>No >>If it is exception to the usual rule only because of tactics then chess >>knowledge in the evaluation cannot help. >> >>I guess that most programs that find Ke8 with no problem simply do not know the >>rule that king in the centre of the board is bad and they may fail in other >>positions (see Ed's post). >> >>If it is a chess knowledge problem there should be a positional rule that >>explains why Ke8 is bad and you should explain the positional reason that Ke8 is >>bad or not claiming that it is a king safety problem. >> >>Uri > >I can add that I remember some nemeth games that suggest that programs do not >punish enough king in the centre so using one position to say that they punish >king in the centre too much is simply wrong. You don't have to used this position only! you can add this position to a set of different positions. This one will help you to avoid overpunishing the king to the center. Otherwise, you will keep increasing the parameter until it becomes too high. I believe that it is always nice to find exceptions to make sure that the program do not behave too bad in those. In other words, you do not have to solve this position quickly, but you have to solve it at one point, in a reasonable time, lets say, 3 minutes. That is a good balance IMHO. After all, it is not such a weird and difficult position. BTW, Ke8 is bad withouth search (for a human eye). The king is trapped in the 8th rank in presence of heavy pieces. That is deadly when one of yours is out of the game (Rh8) even temporarily. In presence of heavy pieces the rule is that the king that is trapped on one side of the board is in a lot of trouble. How to code this is another issue... Regards, Miguel > >Uri
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