Author: Dave Gomboc
Date: 22:01:25 11/16/98
Go up one level in this thread
On November 16, 1998 at 23:46:36, Howard Exner wrote: >On November 16, 1998 at 23:05:49, Howard Exner wrote: > >>On November 16, 1998 at 03:23:54, Harald Faber wrote: >> >>>Hi Ed, >>>I am not sure to reach you via e-mail so I write it here too: >>> >>>I have seen strange behaviour in Rebel10. I have AMD-K6-200 and Laptop166MMX. In >>>the same position the AMD has a diiferent best move with a different value than >>>the 166MMX AT SAME SEARCH DEPTH. How is this possible, any explainations? >> >>I'm noticing something similar when even using the same machine with the >>exact same settings. I tried this with the following position from the >>BS2830 test suite. >> >>r4r1k/pbnq1ppp/np3b2/3p1N2/5B2/2N3PB/PP3P1P/R2QR1K1 w - - id BS2830.EPD; bm Ne4; >> >>The settings for Rebel 10 on my K6-233 were AntiGm=Smart, Combination=Off, >>Selection=N and PlayStyle=N. The method I used was to play the position >>in infinite mode, force the move after about 60 seconds, record the PV >>results, takeback the move and then go through the process from the start. >> >>For 12 takebacks Rebel 10 played the moves in this order: >>ST,A,A,ST,A,A,ST,A,ST,ST,A,ST. (ST means that Rebel 10 played the move >>by setting itself to think in AntiGM=Strong, while A means REbel 10 chose for >>itself AntiGM=Active). Note that the entire time I am using Anti=GM set to Smart >>for the entire test procedure. >> >>This is definitely not making Rebel 10 deterministic when AntiGM is set to >>Smart. Does this mean that when AntiGM is set to smart that different test >>suites will have varying solution times based on what the Smart setting decides >>among the three Choices of Strong, Active or Smart? > >correction here It should read ... three choices of Strong, Active or Off? >> >>My question is why is Rebel 10 chosing different AntiGM settings for completely >>identical positions with the exact same settings? Should Smart mean the >>ability to somehow assess the position and then decide on what AntiGM path >>to follow? >> >>For my own testing and playing against Rebel 10 I'm using AntiGM=Strong, >>Combination=Off, Selection=N (except for some middlegame testing when at >>times I use Selection = 4), and PlayStyle = Agressive. I suspect that Ed is doing some funky stuff with whatever he's got stored in the hash table from previous searches. Rebel might also do position learning to disk, so that it is persisted between sessions, I don't know. Anyway, when the position is re-searched, the differences in whatever has been stored are causing a different degree of anti-GM mode to be made. One interesting thing you might do is to power down your machine between each trial. Another interesting thing you might do is to erase any learn files and power down between each trial. You could then figure out a little bit about what's happening. It's even possible that there is nothing being stored at all, and the differences are due to a pseduorandom number generator. In case it's not already clear, I am merely speculating. I don't own Rebel 10 myself. I would buy it, but I have Rebel 8 and 9 (courtesy Ed, I did some beta-testing) and I don't use them lately because I haven't had a dos/win9x partition in a while. As soon as the Adaptec 2940-U2W support in Linux is stable, I will be installing Linux on my system. Does anyone know if Rebel runs under DOSEMU? Dave Gomboc
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