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Subject: Re: Chess and 2bit EGTBs (win/loss/draw info only)

Author: Vincent Diepeveen

Date: 09:58:00 08/09/02

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On August 09, 2002 at 00:50:04, Robert Hyatt wrote:

for 5 men, uncompressed bittables 6GB or something similar.
Even my own bit less well compressing format it's well under 7 GB.

if you compress that, it fits nearly in RAM... ...so you can probe
anywhere. also qsearch also leaves *everywhere*.

>On August 08, 2002 at 14:43:32, Alvaro Jose Povoa Cardoso wrote:
>
>>If I wanted to play with EGTBs with only win/loss/draw information and no
>>DTM/DTC information where would I place the probe code in the search routine?
>>Taking crafty as an example it has the TB probe code placed next to the hash
>>table probe code and if the current position is in a TB file it returns
>>immediately because is has perfect/complete information. But with 2bit/entry
>>EGTBs it just doesn't seem right to place the code there. It seems logic to me
>>to place the TB probe code in the evaluation function and if a leaf node is in a
>>2bit/entry TB file give it a bonus. Another possibility would be to place the TB
>>probe code before calling the qsearch.
>>Could someone tell me if I'm thinking correctly?
>>
>
>
>No.  You should probe _exactly_ where I do.  The only difference will be
>the "score".  You won't be able to return a mate in N, so you will have
>to doctor the score to some value that says "mate in N where N is large and
>unknown."
>
>If you probe in the eval, you will probe a million times too often.  You
>should probe when you drop into a 5 piece (or smaller) ending, which only
>happens infrequently and immediately after a capture only...  If you do it
>at endpoints, you will get killed tactically because your search depth will
>drop off _several_ plies...
>
>
>
>>Best regards,
>>Alvaro Cardoso



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