Author: Robert Hyatt
Date: 22:07:46 12/10/99
Go up one level in this thread
On December 10, 1999 at 22:53:41, Len Eisner wrote: >On December 10, 1999 at 22:26:43, Chuck wrote: > >>On December 10, 1999 at 20:16:13, Bertil Eklund wrote: >> >>>On December 10, 1999 at 20:01:28, Chuck wrote: >>> >>[snip] >> >>>> >>>>I think it is very easy to prove that Robert is right here. It is very >>>>noticeable. I once played out a 40/2 match between a Mach IV and a Mephisto >>>>Polgar, the Mach IV one 10-2. The two machines are very close in strength, >>>>probably within 100-150 points. But playing many games and watching these two >>>>computers evaluate positions, it was evident that the speed of the Mach IV >>>>(compared to the Polgars 5 Mhz) gave it a big tactical advantage. Head-to-head >>>>this seems to be magnified. I played an old MChess against the Mach IV and it >>>>won 11-1. Wow, what results. The point is, when a progam plays another which is >>>>on significantly slower hardware, the faster program is going to win big and >>>>it's rating will be inflated. Two years later, when it becomes the one with slow >>>>hardware, it will be the one getting pounded, and it's rating will go down. I >>>>think at one time the Mach IV was on the SSDF list at around 2200, but late in >>>>it's life it dropped to below 2100. >>>> >>>>Chuck >>> >>>Hi! >>> >>>As checked houndreds of times this is completely wrong. >>> >>>Play two-houndred games and the level should probably be accurate. >>> >>>Bertil SSDF >> >>Then explain to me how the Mach IV had a SSDF rating of 2282 in January 1993 but >>now has a SSDF rating of 2074!?! >> >>Chuck > >Yes, that is the question, and it applies to the other old programs too. If >computers are anything, they are consistant, so the Mach IV would play exactly >the same today as it did in 1993, yet its rating is over 200 points lower. > >Len You are making a fatal flaw. Elo ratings predict game outcomes. The important number is the rating difference between two programs, not the absolute value of each program's rating. If you play a vs b and get a=2200 and b=2400, that says B should win 3 of every 4 games, roughly. But if B learns, and a doesn't, then you could expect this to widen over time, as a keeps playing the same bad opening lines, while B learns to avoid lines it loses with. Eventually their ratings will be over 500 points apart, because A never varies, and B does. You might prefer that A's rating remain constant and B's rating continues to climb... but Elo is a sort of Newtonian physics model, with equal and opposite movement based on game outcomes... When you think about it, it makes sense...
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