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Subject: Re: History Heuristic

Author: Tord Romstad

Date: 13:11:46 03/18/04

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Hi, Vasik and Mridul!

On March 18, 2004 at 15:31:29, Mridul Muralidharan wrote:

>On March 18, 2004 at 04:43:20, Vasik Rajlich wrote:
>>
>>Yeah, true, this is a big area. Actually secretly I hope to get rid of q-search
>>completely and replace it with a static exchange evaluator. I don't trust a
>>cheap q-search, and don't want an expensive one.

I use a hybrid approach.  Among many other things, my evaluation function
tries to measure the tactical complexity of the position, by considering
the number and values of hanging, pinned or overloaded pieces, and looking
for possible forks.  If the position is sufficiently simple, I replace
the q-search with a SEE.  If it is more complicated, I do a search.
Depending on the position, I search only captures and promotions, or
also promising checks, forks, and moves which bring attacked pieces to safe
squares.

There are still lots of things to improve in my qsearch, but with enough
work I am convinced that it is possible to write a qsearch which is
more reliable than a simplistic capture search, while at the same time
searching fewer nodes.

>>Perhaps you means "singular extensions" (yes I know it was 2:00 am :-)).
>
>
>
>Actually I meant selective extensions.

(Description of idea snipped).

If I understand your idea correctly, I do something similar, but less
extreme.  I extend all checks, but some checks are extended more than
others.

Tord



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