Author: Heiko Mikala
Date: 16:24:56 01/21/98
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On January 21, 1998 at 18:59:08, Stuart Cracraft wrote: >On January 21, 1998 at 18:52:44, Heiko Mikala wrote: > >>I tried Bruce's mate threat extension (everyone did, I guess...), and it >>works fine. > >Could you elaborate on how you tried it, how you tested it, and why you >think it worked? First of all I'm using a "normal" null-move with zero-width window and a depth reduction of 2 plys. Unlike Crafty, I do only extend, if the side to move would be directly mated in the next move. I didn't try the Crafty approach of extending for all mates yet. The test was mainly done on the win at chess position, that was men- tioned here (I guess it was number 141) and the equivalent but easier position number 17 of the BT2630 test. After that I ran the whole BT- test and the Bratko-Kopec test suite to see if there are any negative effects of this extension. As far as I remember there were no negative effects, but the two positions in question were solved 1 ply earlier and much faster in time. I'm sorry, but I don't have the exact test results any more, because at about the same time I added the one-reply- extension and only recorded the results of these two extensions to- gether. By the way, at the moment I'm experimenting with removing some of my extensions, because I think I'm doing to many (or the wrong ones...) On the other hand, I'm "in love" with extensions, and would like to add more of them... ;-) Heiko.
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