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Subject: Re: Crafty and EGTB Question

Author: Dann Corbit

Date: 13:00:44 06/17/04

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On June 17, 2004 at 01:30:54, Ed Trice wrote:

>Hi Mike,
>
>>please post position in FEN format , I will let you know what I get ...
>
>
>It's not really a matter of the results of one single position.
>
>The question is:
>
>Does crafty internally have a "switch" that determines whether or not to probe
>the EGTBs in RAM?
>
>If so, is there a way to "force" it to search?
>
>I have combed over the code and I cannot find anything, and I cannot figure out
>how NONE of the entire 5-piece set of dbs are being encountered.

Take a disk position, and transform it into an EGTB index.

Take a disk head.  Seek to a sector.  Load some blocks into memory.  Decompress
the blocks.  Get the answer from the decompressed pages and return it.

How many evaluations do you think you can perform in this much time?  Hundreds
for sure, maybe thousands.

It is a mistake to probe every possible position.  For sure, it will make your
chess engine play much worse.

If you have bitbase files loaded into ram, it is a good idea to inquire of them
on every position.  But an EGTB probe for every possible probe will cost you 100
Elo, at least.  And the faster the CPU and the more time allocated for the
search, the bigger the penalty.



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