Author: Joachim Rang
Date: 01:31:27 12/13/05
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On December 13, 2005 at 02:16:50, Chrilly Donninger wrote: >I experimented recently with a Shredder-style search in Hydra. The >single-processor Shredder/Hydra completly demolished Shredder. If two programs >are similar, the strength difference is enlarged. Its therefore a bad idea to >tune a programme against itself. >But the Shredder/Hydra made only 40% against Rybka. Changing back to the >standard Hydra-search its between 75-80%. Rybka is regularily "killed" in >king-attacks. As noted before, this numbers are for Hydra-single-processor. The >PC-programm is running on a 3.2 MHz Pentium 4. Time control is 30secs/move. A >standard-opening set similar to the Nunn-openings is used. > >Changing the search is not only a tactical matter. The playing style is to a >large extend also influenced by the search. If two moves are from the evaluation >point similar, the programm usually plays the one with the larger search tree. >Or in other words: The lines which are extended. The Shredder/Hydra played >over-aggressive, whereas the classical Hydra with the right dose. > >One conclusion of my experiment is: Rybka seems to be fairly tuned against >Shredder. This is always the fate of the leader of the gang. In the future other >programs will be tuned against Rybka and it will be much more difficult to stay >on the top. > >The experiment shows also, that it is fairly easy to tune against one programm. >The problem is to find a solution which works against all. > >Chrilly Hi Chrilly, I find that hard to believe. One setting scores 40% against Rybka and another 75-80% but at the same time the latter scores less against Shredder? You did not wrote by how much the more selective search scores better against Shredder but nevertheless in my tests I never experienced something like that. I often experience the same like Vas, that a tuning shows significant improvement in selfplay but no significance against a broad range of opponents. But I never observed that something which helped in selfplay hurts against other engines. It may be without effect against others but not worse. So far I was never able to tune Fruit against a specific opponent which resulted in a signficant difference not to say in doubling the score (40% to 80%). So either I simply lack the understanding how to do this or you played not enough games to get a statistical significant result and observed just noise. Given the little time between your first post about Rybka and this one I give both possibilities the same probability. ;-) regards Joachim P.S.: Given the results of CEGT and various testers Rybka does not seem to score significantly above expectations over Shredder.
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