Author: Don Dailey
Date: 13:25:57 12/26/97
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On December 26, 1997 at 14:27:44, Christophe Theron wrote: > >On December 26, 1997 at 12:26:23, Don Dailey wrote: > >>Perhaps they are doing heavy pruning on the computers moves? If you >>modify the selectivity such that much heavier pruning takes place >>on the computers side you might arrarnge extra depth that results in >>play that is safe but not opportunistic for the computer. >> >>I remember Richard Langs programs USED to have the characteristic >>that they would see anything you could do to them. In some experiments >>me and Larry Kaufman did, it would quickly see that you could win >>a piece and avoid the loss. But if you forced the piece losing move >>and let it think for the winning side, it could not find the win without >>a very long think! Very strange. But this was the best program in the >>world and pehaps still is. >> >>But this makes some sense to me. I don't think a single chess game has >>ever been won without an error on the losing side. If your program >>NEVER made an error (you wish!) it would never lose (unless of course >>the opening position is a loss for one side or the other.) > >I have tried recently to modify Tiger this way. First, I changed the >time allocation policy to allow the program to play only when the last >move in the main line was a computer's move. This allows the program to >detect more deep threats. Second, I made a more agressive selection on >Tiger's move. So he could miss a combination for him, but wouldn't miss >an opponent' s combination. > >In average, this new version shows deeper lines (1 ply more). > >I let the program run a long self play against the previous version >(exactly the same program except for the two above changes). The rate of >play was 5mn/game on a P100, 4Mb hash. > >Result: no improvement at all. The score was very close to 50%. > >In addition, the new version performs poorly on combination tests. > >I've made several others tests with differents changes, trying to prove >the idea was good, but I didn't succeed. > >Still I believe that the idea of being very cautious and conservative >has some value. I think I didn't catch the right way to do it. > > > Christophe Hi Christophe, This reminds me so much of my experiments (but not the same issue of playing it safe.) I will try an interesting idea, self-test the hell out of it and almost always end up very close to 50-50 (but often on the low side!) I have been through this cycle a million times! But once in a while, BINGO! And I always come away with the feeling that perhaps I didn't implement it quite right! -- Don
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