Author: Tom Likens
Date: 07:44:05 05/20/04
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On May 19, 2004 at 17:08:38, Will Singleton wrote: >On May 19, 2004 at 15:40:35, Tom Likens wrote: > >> >>Afternoon all, >> >>I've been reworking some of the evaluation elements of my engine >>and one of the items I wanted to modify is the scoring of pinned >>pieces. So with that in mind I thought I'd share some my thoughts >>on the subject (and maybe obtain a few new ideas in the process). >> >>Currently, I'm including this items my pinned pieces evaluator. >> >>1. If one side is pinning a piece *and* has the right to move, then use >> the SEE function to determine if the piece can be profitably captured. >> >>2. If a piece is "absolutely" pinned (a Nimzowitsch term) penalize it. >> An absolute pinned piece can't move at all (e.g. a knight pinned to >> the king by an enemy bishop would be an absolute pin, whereas >> a bishop pinned to the king by a queen would not be since the bishop >> could move along the diagonal of the pin). >> >>3. If the piece is absolutely pinned and the attacking piece's value is >> less than the value of the pinned piece (regardless of who has the >> move) penalize the defender a percentage of the difference between >> the attacking piece and the pinned piece. >> >>4. If the attacker has a queen/rook, queen/bishop or rook/rook battery >> attacking the pinned piece then increase the penalty. >> >>5. If multiple pieces are pinned increase the penalties. Also if multiple >> pieces are pinned then accessed the pinned side some percentage >> of the *largest* pinned piece from either 1 or 3 above. >> >>As I mentioned earlier, I'd be interested in how others handle pinned >>pieces. I'd also be interested in just hearing thoughts on the above and >>if I've missed anything obvious. >> >>cheers, >>--tom > >I tried using a pin detector in my see(), but it didn't seem to help so I >dropped it. With respect to your item (1) above, the qsearch should handle that >case. I had the same experience. It seemed to be a natural extension to SEE but the payoff wasn't really there. The only caveat to this is that I tried it a long time ago when my qsearch was *much* simpler, so it might payoff now. It won't go in this version of the program, but I may experiment with it and see if it's worthwhile for inclusion in a future release. --tom
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