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Subject: Re: If you like to solve easy mate...

Author: Pete Galati

Date: 08:42:40 02/08/01

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On February 08, 2001 at 11:31:35, leonid wrote:

>On February 08, 2001 at 10:45:07, Heiner Marxen wrote:
>
>>On February 08, 2001 at 10:09:29, leonid wrote:
>>
>>>On February 08, 2001 at 09:49:16, Pete Galati wrote:
>>>
>>>>On February 08, 2001 at 08:21:44, leonid wrote:
>>>>
>>>>>Hi!
>>>>>
>>>>>If you like to solve easy (not deep) forced mate position, here is the one.
>>>>>
>>>>>[D]Nb1rkrNb/1n1pqp1b/n2qqq1n/1NNNNNNn/2BNNB2/1R2Q1R1/8/2K5 w - -
>>>>>
>>>>>Please, indicate your result.
>>>>>
>>>>>Thanks,
>>>>>Leonid.
>>>>
>>>>Crafty found the mate in 8 a little bit earlier but it had it's hashtables all
>>>>filled up, and I can't operate it at up to 96mb hashtables on my computer, so
>>>>I'm stuck with 48 at the moment.  I never get around to mentioning, it's a
>>>>700mhz Celeron.
>>>>
>>>>Pete
>>>>
>>>>5 piece tablebase files found
>>>>1836kb of RAM used for TB indices and decompression tables
>>>>EGTB cache memory = 3M bytes.
>>>>hash table memory = 48M bytes.
>>>>pawn hash table memory = 5M bytes.
>>>
>>>Simply can't detain my curiosity, what is the "pawn hash table"? Special hash
>>>table just for pawns?
>>
>>Yes, for that part of the eval which is based only on the location of
>>all the pawns (pawn structure).
>>
>>
>>>Thanks for detailed decription! Sometime, some very interesting moments come to
>>>light.
>>>
>>>My program found at the same depth mate but I not looked by brute force. It
>>>could be that somebody will come with shorter mate.
>>>
>>>Leonid.
>>
>>I doubt it.  Chest says "no mate in 7" after 68.4 minutes.
>>You all found the shortest mate:  Congratulations!
>
>Thanks, but I doubt very much that my program will search 7 moves in one hour.
>It had awful branching factor and in 5 moves already went to 10 min. Selective
>search make me feel this by solving position by easiest level (8 moves deep)in
>18 sec. Usually it should be only split of one second for 8 moves, for that
>search level.
>
>Brute force search:
>
>3 moves - 0.38 sec
>4 moves - 22.3 sec
>5 moves - 9 min 52 sec
>
>Leonid.

Here's a paragraph from Bob's Crafty doc file related to the pawn hashtables:

"23.   hash=x  and hashp=x  These commands are used to adjust
the size of the hash tables in Crafty.   hash  modifies  the
size of the transposition/refutation table, while hashp mod-
ifies the size of the pawn structure/king safety hash table.
The  sizes  may be entered as one of the following two types
of values: nnnK where nnn is an integer indicating how  many
Kbytes Crafty should use for this hash table; nnnM where nnn
is an integer indicating how many Mbytes Crafty should  use."

Pete



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