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Subject: Re: How to store quiescence search results in transposition tables?

Author: Robert Hyatt

Date: 11:24:43 09/06/00

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On September 06, 2000 at 13:42:26, Larry Griffiths wrote:

>On September 06, 2000 at 13:38:27, Robert Hyatt wrote:
>
>>On September 06, 2000 at 11:06:42, Philipp Claßen wrote:
>>
>>>Hi!
>>>
>>>I want to add a extra transposition table for quiescence search to my own
>>>program. But I´m not sure how to avoid that important entries are overwritten by
>>>less important ones. In a normal search the distance is a good criterion but in
>>>a quiescence search? Perhaps the current ply?
>>>
>>>Phil
>>
>>
>>I don't store q-search nodes, although a couple of years ago I did.  I don't
>>think it will make any difference in all in performance.  The cost of the
>>probes is offset by the value of the hit, almost exactly.  So doing it or
>>not won't make you any faster.  And since not doing it didn't hurt at all,
>>I got rid of it for two reason.  1.  It made the q-search code a bit simpler,
>>and simpler is always better.  2.  For big searches with small hash tables,
>>it makes much more effective use of available memory since the q-search stuff
>>is the majority of the nodes searched, and they don't compete for table space
>>at all.
>>
>>If you want to store them, just store "depth" but let it go negative into the
>>q-search.  the first ply of q-search would be 0, the next would be -1, etc.  Or
>>you can do as I did and always store 0 which is reasonable.
>
>I have a question Bob.
>
>Should all moves be generated in a q-search, or just captures?
>
>Larry.


Depends on your q-search.  In crafty, captures are _all_ I look at, and I don't
pay any attention to checks or other kinds of moves.  In Cray Blitz, I did all
moves as the selective code could include things besides captures if it wanted
to.




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