Author: Uri Blass
Date: 23:58:13 06/14/02
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On June 15, 2002 at 00:20:48, Robert Hyatt wrote: >On June 13, 2002 at 23:58:46, Christophe Theron wrote: > >>On June 13, 2002 at 09:13:43, Robert Henry Durrett wrote: >> >>>On June 13, 2002 at 06:00:13, Jorge Pichard wrote: >>> >>>>Hiarcs 8 was NOT made for slow computer such as an AMD 450 Mhz as the SSDF >>>>decided to test it against Nimzo 8. >>> >>>What, exactly, causes this problem? >>> >>>Do other chess engines have this same problem too? >>> >>> >>>Bob D. >> >> >> >>The problem is that the problem described above does not exist. >> >> >> >> Christophe > >Here we disagree significantly. > >One trivial case... Take a program that uses null-move R=2 or 3, and run >it on a very slow machine. Then on a very fast machine. The slow machine >will make significant blunders because the R=2 or R=3 depth reduction will >be a killer. This problem can be easily solved if you do not use R=2 or R=3 when the expected depth to search is small. I do not say that it is the best solution but the cost of one if command for the speed of the program is close to nothing. Another obvious option to try can be not using null move pruning when the remaining depth is small. I did not investigat the problem because I found that in the middle game R=2 was productive for Movei in all time controls that I tried but it is possible that even blitz on p800 is too fast(I tested it only on p800) and I need to test it even at faster time control(I have no problem to do it because I have an option to let Movei play faster by believing that it really has less time so I can make it believe under winboard that it has only 12 or 6 seconds per game when it really has a minute). Note that Crafty on a slow p500 won a bullet tournament(1 minute per game) against other amateurs. see http://www.computerschachecke.de/Tournaments/Tables/BulletA.htm I guess based on that information that it does not make significant blunders inspite of the R=2 or R=3 and the fast time control. If you consider the fact that bullet on p500 is eqvivalent to slower time control on slower machines then I suspect that your R=2 or R=3 is not a problem even on very slow machines like 486 if you are interested on standard time control. Uri
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