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Very Hot Topic (More than 25 Replies) Stockfish 9 Released ! (Read 12495 times)
GMTonyKosten
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Re: Stockfish 9 Released !
Reply #13 - 03/01/18 at 12:25:39
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proustiskeen wrote on 03/01/18 at 03:17:28:
I compiled Stockfish 9 with contempt=0. You can download it here:


I downloaded this OK (I ignored the 'notification'), but it wouldn't run on my ChessBase, is it a Windows version?
  
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TD
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Re: Stockfish 9 Released !
Reply #12 - 03/01/18 at 08:12:20
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proustiskeen wrote on 03/01/18 at 03:17:28:
I compiled Stockfish 9 with contempt=0. You can download it here:

https://chessbookreviews.wordpress.com/stockfish-9-for-analysis/

I tried to download this, but got some voice telling me that my computer was infected by a virus and I had to follow their instructions???
  
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proustiskeen
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Re: Stockfish 9 Released !
Reply #11 - 03/01/18 at 03:17:28
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I compiled Stockfish 9 with contempt=0. You can download it here:

https://chessbookreviews.wordpress.com/stockfish-9-for-analysis/
  
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brabo
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Re: Stockfish 9 Released !
Reply #10 - 02/28/18 at 09:40:13
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GMTonyKosten wrote on 02/28/18 at 09:17:37:
brabo wrote on 02/27/18 at 16:46:17:
I am really annoyed by this contempt factor which was increased to 0,2


Does this make game analysis less accurate than when using Stockfish 8?

Very good question but very hard to answer. I see 2 reasons.
1) It depends if you are able to properly interpret the effect of the contempt factor. I just checked a position in which Stockfish 9 with contempt gives a small edge. However without the contempt it shows equal as the evaluation just drops below the threshold. Equal is definitely a more accurate assessment. Not taking the effect of the contempt into account will definitely cause for some positions a less accurate assessment with Stockfish 9 compared to Stockfish 8.
2) However it would be an error to attribute the full rating-gain of Stockfish 9 purely to the contempt-introduction. Many other things were also adapted. I have noticed for some specific positions already an improvement in analysis by Stockfish 9 which reverted some earlier done analysis by Stockfish 8.

So the answer isn't straightforward. Anyway I do believe that Stockfish 9 without contempt is better to analyze than Stockfish 8.
  
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brabo
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Re: Stockfish 9 Released !
Reply #9 - 02/28/18 at 09:27:19
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El_Commandante wrote on 02/28/18 at 09:05:38:
[quote author=5A4A595A57380 link=1517489222/6#6 date=1519804771]

As far as I know, in tournaments the settings of an engines must be on default. Under this circumstances setting the contempt factor to 0 would mean, that Stockfish would make a lot of draws against weaker engines (i.e. by allowing a repetition in a slightly worse position). This can be avoided by setting the contempt factor to 20.

Which tournaments are you talking about? For TCEC any programmer can submit their preferred version of the engine. That has nothing to do with providing a site with 1 or more versions of an engine (I would like best version to analyze and best version to play). In fact stockfish does provide different versions to download on their development page. I couldn't find the one specific without contempt but you could find e.g. a brand-new one introducing a dynamic contempt feature.
  
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GMTonyKosten
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Re: Stockfish 9 Released !
Reply #8 - 02/28/18 at 09:17:37
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brabo wrote on 02/27/18 at 16:46:17:
I am really annoyed by this contempt factor which was increased to 0,2


Does this make game analysis less accurate than when using Stockfish 8?
  
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El_Commandante
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Re: Stockfish 9 Released !
Reply #7 - 02/28/18 at 09:05:38
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brabo wrote on 02/28/18 at 07:59:31:
Yes that works fine. It would be good to have such version available to download for everybody. Maybe it is already somewhere but I couldn't find so via a general search. I guess many will find it difficult to execute your solution. I believe most players are using the engines in the first place to analyze positions and only secondary to let them play. More I will likely write about in a later article on my blog.


As far as I know, in tournaments the settings of an engines must be on default. Under this circumstances setting the contempt factor to 0 would mean, that Stockfish would make a lot of draws against weaker engines (i.e. by allowing a repetition in a slightly worse position). This can be avoided by setting the contempt factor to 20.
  
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brabo
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Re: Stockfish 9 Released !
Reply #6 - 02/28/18 at 07:59:31
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proustiskeen wrote on 02/27/18 at 19:57:19:
The short answer is that you'll have to compile your own version and modify the ucioptions.cpp file to remove the contempt by setting it to 0.

Yes that works fine. It would be good to have such version available to download for everybody. Maybe it is already somewhere but I couldn't find so via a general search. I guess many will find it difficult to execute your solution. I believe most players are using the engines in the first place to analyze positions and only secondary to let them play. More I will likely write about in a later article on my blog.
  
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TD
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Re: Stockfish 9 Released !
Reply #5 - 02/28/18 at 04:38:26
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ErictheRed wrote on 02/28/18 at 02:43:02:
What is the contempt factor?

‘The contempt feature of Stockfish tries to prevent the engine from  simplifying the position too quickly when it feels that it is very slightly behind, instead keeping the tension a little bit longer. This november discussion left open the decision of which “default”  value for contempt we should use for Stockfish, taking into account  the various uses of Stockfish (opening preparation for humans, computer online tournaments,analysis tool for web pages, human/computer play,
etc).  This pull request proposes to set the default contempt value of SF to twenty centipawns, which turns out to be the highest value which is not a regression against current master, as this seemed to be a good compromise between risk and safety.’
  
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Re: Stockfish 9 Released !
Reply #4 - 02/28/18 at 02:43:02
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What is the contempt factor?
  
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proustiskeen
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Re: Stockfish 9 Released !
Reply #3 - 02/27/18 at 19:57:19
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The short answer is that you'll have to compile your own version and modify the ucioptions.cpp file to remove the contempt by setting it to 0.
  
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TD
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Re: Stockfish 9 Released !
Reply #2 - 02/27/18 at 18:26:56
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brabo wrote on 02/27/18 at 16:46:17:
I started to use Stockfish 9 but I am really annoyed by this contempt factor which was increased to 0,2. I am used to classify lines of an opening by their engine-evaluation but now this contempt factor spoils the accuracy.
Yes I know it is easy to switch off this contempt factor but each time I switch between engines the default setting is restored and I have to do it over again. Does somebody has an easy fix for that?

Brabo, I have mentioned your problem at the Dutch site https://www.schaaksite.nl/2018/02/23/stockfish-9-sterker-door-minachting-tegenst....
Maybe that will provide you with an answer.
  
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brabo
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Re: Stockfish 9 Released !
Reply #1 - 02/27/18 at 16:46:17
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IM_Serious wrote on 02/01/18 at 12:47:02:
Stockfish 9 Released !

stockfishchess.org/download/

I started to use Stockfish 9 but I am really annoyed by this contempt factor which was increased to 0,2. I am used to classify lines of an opening by their engine-evaluation but now this contempt factor spoils the accuracy.
Yes I know it is easy to switch off this contempt factor but each time I switch between engines the default setting is restored and I have to do it over again. Does somebody has an easy fix for that?
  
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IM_Serious
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Stockfish 9 Released !
02/01/18 at 12:47:02
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Stockfish 9 Released !

stockfishchess.org/download/
  
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