contempt = 20 ?

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ZeusII

17 Jul, 2014 02:46 PM

Maybe this recent change is OK for engine vs engine matches used to rate engines and determine relative Elo, but I doubt it is correct for correspondence chess where it can be assumed that opponent also has Stockfish. Wouldn't contempt = 0 be a better setting when Stockfish is playing vs itself (i.e. Stockfish)?

  1. 1 Posted by dskldsakildaskl... on 18 Jul, 2014 04:44 AM

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    Your question is misleading because you really mean whether the change would decrease the playing strength relative to the playing strength before the change.

    As Lucas has proved with a regression test, https://github.com/official-stockfish/Stockfish/commit/67a5e1ecf97e.... There is little strength change. LOS is 53% which means it's likely the new change has very little strength change. The test statistic and the confidence interval prove it as well.

    So, no, contempt = 0 doesn't make the engine play better against itself.

    Note that the change is motivated by the fact that Stockfish plays weaker against weaker opponents relatively to say Houdini. SF DD was a stronger engine than Houdini, but Houdini leaded all rating list because it played better against weaker engines. With this change, SF 6 will further widen the rating gap and solidify it's #1 status.

  2. 2 Posted by ZeusII on 18 Jul, 2014 06:00 AM

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    There's nothing misleading about my question. Your response is dubious IMO.

  3. 3 Posted by doaidsiasdasaoi... on 18 Jul, 2014 06:50 AM

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    Ok, if you know the proper response, why ask? Please state what's dubious and reasons why.

  4. 4 Posted by ZeusII on 18 Jul, 2014 07:27 AM

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    I'll await a more cogent reply from someone else...

  5. 5 Posted by dasdasdkasdasdk... on 18 Jul, 2014 08:06 AM

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    Ok. So you're expecting someone to come and tell you: "Yes, contempt=0 is a better setting for playing against itself. Lucas has made a mistake with the commit so he's an idiot and he needs to revert the change.".

  6. 6 Posted by ZeusII on 20 Jul, 2014 06:39 PM

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    Lucas has reverted to contempt = 0 in his new update this morning based on another obscure statistical study.

    I had already done so, based on common sense alone! Consultation is free. Just ask... ;>)

  7. 7 Posted by anthony on 03 Feb, 2017 08:14 AM

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    To me "contempt" has an implication of the way human players compete. If there's contempt for an opponent, one would rather lose than to draw. Whereas if no contempt exists, one is more likely to accept a draw. With Stockfish however, (and I'm probably wrong) "contempt" means something different because at the minimum setting, it becomes as if a search for a draw takes precedence over a search for a win. In other words, it will forego a win if a draw is possible.

  8. 8 Posted by george wet on 25 Jun, 2018 10:43 PM

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    contempt means the software values it's own pieces more than it's opponents, making it less likely to exchange and simplify. 0 contempt is the only right setting to analyze a position, no matter the engine..

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