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Subject: Re: History Heuristic

Author: Mikael Bäckman

Date: 02:50:57 03/17/04

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On March 17, 2004 at 05:26:30, Sune Fischer wrote:

>On March 17, 2004 at 05:17:43, Mikael Bäckman wrote:
>
>>>Just a single test position to depth 15:
>>
>>
>>Testing on a single position is wrong.
>>If you take 20 positions and repeat the test, are the results still the same?
>>
>>/Mikael
>
>True.
>
>I have tested on other positions back when I started using this, but as you can
>see it takes a long time for each position so I just tried a single one this
>time.
>If the search is deep enough I always get the same pattern with the local
>overtaking the global.
>
>It would be interesting to see if Crafty and other engines exibit the same
>behavior, I would expect so but one never knows :)
>
>-S.

I can run some tests when I get home, but I would need to know exactly how you
'localize' the HH. Divide with X every N nodes?
My history tables in chepla look like history[stm][piece][to], it will be
interesting to compare the numbers.

One thing to check before running these tests.
I had a bug a while ago where my History tables would overtake the good captures
in movesorting: I add a base value of B for all good and equal captures. In some
deep searches (mostly endgames searches) history values would become greater
than B...

/Mikael





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