To Mark Lefler

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TShackel
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To Mark Lefler

Post by TShackel » Sat Sep 12, 2015 5:15 pm

Hi Mark,

I was wondering what you set contempt at for stage 2 of TCEC?

Thanks.

Tim.

petronik
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Re: To Mark Lefler

Post by petronik » Sat Sep 12, 2015 8:07 pm

Hi Mark!

I cannot find "contempt" in the configuration of my copy of Komodo 9.02 recently upgraded from 9.01.
Thanks in advance for your help!

Marco

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RJN
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Re: To Mark Lefler

Post by RJN » Sat Sep 12, 2015 11:30 pm

petronik wrote:Hi Mark!

I cannot find "contempt" in the configuration of my copy of Komodo 9.02 recently upgraded from 9.01.
Thanks in advance for your help!

Marco
I think there is some confusion, Komodo 9.02 only has "drawscore". It is Komodo 9.2 that has "contempt".

http://talkchess.com/forum/viewtopic.php?t=57325

However the most significant change introduced in Komodo 9.2 is "Contempt", which replaces "Drawscore". This is not just a name and sign change. Contempt now incorporates the concept of trying to keep more pieces on the board until you are winning, when playing a weaker opponent. The default value of 15 (centipawns) is probably optimum for playing engines rated around a hundred elo or so below Komodo 9.2. Against a close rival (of which there is currently only one other than Komodo 9.1) best results will be obtained with a smaller contempt value, perhaps 5. Against most other engines a larger value like 20 or 25 should work even better than the default. Against humans I suggest using 40 for Grandmasters, 50 for Masters, and 75 for strong amateurs. Even larger values are suitable for handicap games. Note that in game play Contempt will cause the score reported by Komodo to be optimistic; in analysis mode (infinite search) Contempt is automatically set to zero.
The release came too late to be used in the first stage of TCEC, but of course it will be available for the second stage. We anticipate using Komodo 9.2 in Sunday's two pawn handicap match with Grandmaster Petr.
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shrapnel
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Re: To Mark Lefler

Post by shrapnel » Sun Sep 13, 2015 4:32 am

RJN wrote:"The release came too late to be used in the first stage of TCEC, but of course it will be available for the second stage.
Hmm...though a Komodo fan, I'm not too sure about this new Contempt parameter. The Komodo Team insists on retaining it; and indeed it may prove beneficial in the long run.
The only thing is, I'm not too sure that the ideal Contempt setting to use against Stockfish has been found yet....
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Re: To Mark Lefler

Post by mjlef » Sun Sep 13, 2015 11:14 pm

TShackel wrote:Hi Mark,

I was wondering what you set contempt at for stage 2 of TCEC?

Thanks.

Tim.
It is set to the default, which is 15. Per the readme file, this will discourage Komodo from accepting early draws, and make it keep playing even if it is down a bit. In later stages (assuming we make the next stage), we will probably lower it a bit.

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Re: To Mark Lefler

Post by mjlef » Sun Sep 13, 2015 11:17 pm

shrapnel wrote:
RJN wrote:"The release came too late to be used in the first stage of TCEC, but of course it will be available for the second stage.
Hmm...though a Komodo fan, I'm not too sure about this new Contempt parameter. The Komodo Team insists on retaining it; and indeed it may prove beneficial in the long run.
The only thing is, I'm not too sure that the ideal Contempt setting to use against Stockfish has been found yet....
"insists" is a very strong word. The Komodo Team keeps things in the program that have been shown to increase strength overall. In fact, since 9.2, we have started using the Contempt value for other things to improve play. We are learning a lot from the Odds matches we have been running, so hopefully new things will come up we can use to further improve Komodo.

lkaufman
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Re: To Mark Lefler

Post by lkaufman » Mon Sep 14, 2015 2:37 am

shrapnel wrote:
RJN wrote:"The release came too late to be used in the first stage of TCEC, but of course it will be available for the second stage.
Hmm...though a Komodo fan, I'm not too sure about this new Contempt parameter. The Komodo Team insists on retaining it; and indeed it may prove beneficial in the long run.
The only thing is, I'm not too sure that the ideal Contempt setting to use against Stockfish has been found yet....

We wouldn't have bothered with contempt if we only cared about playing Stockfish, it may well be worthless against latest SF. But you can just set it to zero against SF if you like. In view of our ratings on the rating lists, it is clearly helping us against the range of opponents tested there.
Komodo rules!

shrapnel
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Re: To Mark Lefler

Post by shrapnel » Mon Sep 14, 2015 12:51 pm

lkaufman wrote:We wouldn't have bothered with contempt if we only cared about playing Stockfish,
Fair enough, from YOUR perspective.
From a Gamer's perspective, I can tell you this......Open up ANY online chess Server like Playchess.com or Infinitychess.com and you will find that 99.99 % of the players using Komodo, Stockfish or one of its derivatives.
NO self-respecting player would be caught dead using ANY other Engine !
It's only in this Forum that people get excited about mostly unheard of Engines. In the real (Gaming) world all Engines except Komodo and Stockfish are simply SNEERED at !
That is the reality ! AND THAT is why it is important for many Komodo users to find the ideal Contempt to use against Stockfish, not simply use an over-defensive contempt 0 !
Regards
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lkaufman
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Re: To Mark Lefler

Post by lkaufman » Mon Sep 14, 2015 1:26 pm

shrapnel wrote:
lkaufman wrote:We wouldn't have bothered with contempt if we only cared about playing Stockfish,
Fair enough, from YOUR perspective.
From a Gamer's perspective, I can tell you this......Open up ANY online chess Server like Playchess.com or Infinitychess.com and you will find that 99.99 % of the players using Komodo, Stockfish or one of its derivatives.
NO self-respecting player would be caught dead using ANY other Engine !
It's only in this Forum that people get excited about mostly unheard of Engines. In the real (Gaming) world all Engines except Komodo and Stockfish are simply SNEERED at !
That is the reality ! AND THAT is why it is important for many Komodo users to find the ideal Contempt to use against Stockfish, not simply use an over-defensive contempt 0 !
Regards
In my opinion the proper value for you to use in gaming depends very much on relative hardware. For example, if you only have an 8 core machine while your opponent has 24 cores, you might well want to use negative contempt. If you have 8 cores and he only has a quad, probably the default contempt (or maybe just 10) is fine. But perhaps often you don't know the opponent's hardware.
Komodo rules!

TShackel
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Re: To Mark Lefler

Post by TShackel » Mon Sep 14, 2015 6:11 pm

lkaufman wrote:We wouldn't have bothered with contempt if we only cared about playing Stockfish, it may well be worthless against latest SF. But you can just set it to zero against SF if you like. In view of our ratings on the rating lists, it is clearly helping us against the range of opponents tested there.
I agree Larry that the new contempt is helping you on the rating lists. Your draw percentage has gone down steadily from 9.0, to 9.1, and especially to 9.2. And 9.2's win percentage has gone up at the same time the draw percentage went down. That sounds like a big plus in my book!

You did it! You mad Komodo a more interesting engine due to contempt and also I liked increasing dynamic weights as well!

Sincerely,

Tim.

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