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Subject: Re: Question on History heuristic

Author: Will Singleton

Date: 11:22:29 10/06/99

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On October 05, 1999 at 21:04:40, Peter Kappler wrote:

>On October 05, 1999 at 16:36:59, William Bryant wrote:
>
>>When updating the history for a move that has generated a cutoff,
>>what value to people use.
>>
>>Do you use ply or some function of ply which means that the closer you are to
>>the leaves, the greater the value being used for updating?
>>ie: History[from][to] += ply;
>>
>>Do you use depth or some function of depth which means the closer you are to the
>>root, the greater the value being used for updating?
>>ie: History[from][to] += ply;
>>
>>Or are there other values being used.
>>
>>Thank you in advance.
>>
>>William
>>wbryant@ix.netcom.com
>
>
>Hi William,
>
>I think moves that cause a cutoff near the root should get a higher bonus, as
>they have been searched more deeply.  In Grok, I increment the history score by
>2^depth, which greatly favors moves that cause cutoffs near the root.  I think I
>got the exponential scoring idea from an ICCA article, but I can't recall the
>author.
>
>--Pete

Jonathan Schaeffer, ICCAJ Aug 1983, pp 16-19.  There have been other articles
since then, which expand on this and compare the effect of HH with other
move-ordering techniques.  I can't find the particular one I'm thinking of.

Will




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