Author: Scott Gasch
Date: 09:46:47 12/01/00
Hi all, I've been reading an ICCA article about Interior Node Recognizers and thinking about adding them to my search. There are examples for KBBvK and KBNvK in this article. The "score" that the recognizers return for a position are based on the material balance, a bonus for having a recognized win, the distance between the kings and the distance between the lone king and the (correct) corner of the board. The bonus for winning is only 2.5 pawns, if I understand this article correctly? Why is this so low -- if it's a recognized winning position shouldn't the bonus be enough to make it stand out among other configurations that could occur in the search tree? Say I wanted to implement a KBvKB, KNvKN or KBvKN recognizer... these are draws unless side to move can mate with one move or unless a bad opponent moves into a losing configuration. So would the way to do this be to recognize the configurations where side to move has mate in 1 and return MATE-1 score for these otherwise return draw? [D]KB/8/k/1b/8/8/8/8 b - - 0 0 Is it worth implementing these types of things when there are endgame databases available? Does anyone else do these and, if so, what positions do you recognize? A good recognizer for won KP*vKP* endgames would be invaluable but difficult to implement. I see some of this type of code in crafty's eval -- was the overhead of recognizing at every search node too high? Why is this in the eval as opposed to in search? If a dumb opponent bumbles into the mate-in-1 KBvKB position from a series of drawn positions, how can search see and react to this given that, as described in the article I read, there is no move associated with the score returned by the recognizer. If this happens at an interior search node won't the last move be missing from the PV? How will it ever see checkmate if we return MATE-1 and cut off the search at the position above? Does it just wait until this is the current board position and let the search find the one winning move then? Thanks for the help, Scott
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