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Subject: Re: Quiescence vs swapoff

Author: Robert Hyatt

Date: 17:18:00 04/15/98

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On April 15, 1998 at 13:26:54, Peter Fendrich wrote:

>On April 15, 1998 at 13:12:57, Christophe Theron wrote:
>
>>On April 15, 1998 at 13:01:42, Peter Fendrich wrote:
>>
>>>I am trying a swapoff algorithm (sometimes called SEE) instead of the
>>> more classic quiescence search.
>>>The extra time saved by this can be used for more agressive extensions
>>>or better evaluation.
>>>The drawback is of cource the increased risk for tactical mistakes.
>>>
>>>In short depths the swapoff makes too many mistakes to be useful but
>>>when the depth increases I see less of the mistakes but still have
>>>that extra time it saves for me.
>>>
>>>In my opinion it should be a break even, at some depth limit, between
>>>these two alg's and beyond that limit the swapoff is the best choice.
>>>
>>>Comments?
>>>
>>>/Peter
>>
>>The swapoff idea is the first thing that comes in mind when someone
>>begins to write a chess program. That's how I begun, at least.
>>
>When I wrote my first chess program about 1980 SEE wasn't a known
>concept, at least not for me!
>
>>IMO it is not as fast as a simple QSearch. This is counterintuitive, but
>>as depth increase, QSearch has less and less job to do, because there
>>are more and more alphabeta cutoffs before or on entering in the
>>QSearch.
>
>The SEE code itself should be faster than Qsearch, shouldn't it?
>


yes... no recursive calls, and so forth.  *but* it will fail in the wild
tactical positions, and win in the quiet positions.  You have to choose
which you like.




>>
>>On the other hand, a SEE has always the same amount of job to do,
>>whatever the depth is. In any case, more job than QSearch.
>>
>I dont't follow you here. If QSearch has less job to do, then the SEE
>has as well. The QSearch is just replaed by the SEE.
>
>>And I don't even mention the huge blunders you will never get rid off
>>with your SEE, even if you make it very clever.
>>
>>Just my opinion, based on experience.
>>
>>Anyway, writting a good SEE is useful, because you can use it for
>>selection purposes.
>
>I have two versions of SEE, a fast one used to order generated captures
>and one more accurate and slower to replace the QSearch.
>
>>
>>
>>    Christophe



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