Why does stockfish randomise draw evaluations?

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konsolas
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Why does stockfish randomise draw evaluations?

Post by konsolas » Sun Sep 01, 2019 10:55 am

In search.cpp:value_draw, Stockfish randomly adds or subtracts 1 to the draw score if the depth is > 3: https://github.com/official-stockfish/S ... pp#L88-L92

The comment is that this helps "avoid 3fold-blindness". What exactly does this mean? Are there any concrete examples of positions where this random component in draw evaluations notably changes the search result?

zullil
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Re: Why does stockfish randomise draw evaluations?

Post by zullil » Sun Sep 01, 2019 11:31 am

konsolas wrote:
Sun Sep 01, 2019 10:55 am
In search.cpp:value_draw, Stockfish randomly adds or subtracts 1 to the draw score if the depth is > 3: https://github.com/official-stockfish/S ... pp#L88-L92

The comment is that this helps "avoid 3fold-blindness". What exactly does this mean? Are there any concrete examples of positions where this random component in draw evaluations notably changes the search result?
https://github.com/official-stockfish/S ... 7fc6509886

konsolas
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Re: Why does stockfish randomise draw evaluations?

Post by konsolas » Sun Sep 01, 2019 7:51 pm

Thanks, that's very interesting.

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xr_a_y
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Re: Why does stockfish randomise draw evaluations?

Post by xr_a_y » Fri Sep 13, 2019 5:41 pm

konsolas wrote:
Sun Sep 01, 2019 7:51 pm
Thanks, that's very interesting.
Vincent, did you tried that?
This seems to be winning some elo for Minic.

konsolas
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Re: Why does stockfish randomise draw evaluations?

Post by konsolas » Fri Sep 13, 2019 6:49 pm

I'd love to, but I haven't worked on Topple much recently.

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