Discussion of chess software programming and technical issues.

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Cardoso
Posts: 362
Joined: Thu Mar 16, 2006 7:39 pm
Location: Portugal
Full name: Alvaro Cardoso

Post by Cardoso »

Hi Daniel :)
I have a doubt on your code that relaxes alpha on a FL and beta on a FH.
You have the code:

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//delta *= 2;
//delta += delta / 2;
delta += delta / 3 + 4;
I see you have experimented with several values, but my doubt is:
Is this line really correct and what you really intended to do?

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delta += delta / 3 + 4;
The value "+4" is so small it caught my attention.
Or did you really want to increase delta by 3/4 of itself like this?:

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delta += delta * 3 / 4;
I know small increments on delta prunes more and the tree is smaller, but it also occurs more researches on FLs and FHs.
thanks,
Alvaro
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cdani
Posts: 2204
Joined: Sat Jan 18, 2014 10:24 am
Location: Andorra

Andscacs delta += delta / 3 + 4

Post by cdani »

This test was not driven by any special concept or whatever. Was just a little change that obtained maybe 0.5 elo more than previous delta += delta / 2 :-)
I see that Stockfish has
delta += delta / 4 + 5;
so probably the rough idea was taken from it.

Is in the big list of things pending to try better adjustments.