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Subject: Re: Ideas to reduce size of tablebases

Author: Ernst A. Heinz

Date: 02:38:08 09/01/98

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On September 01, 1998 at 04:39:24, Rémi Coulom wrote:
>
>On August 31, 1998 at 21:42:47, Eugene Nalimov wrote:
>
>>
>>I wrote generator that use those and several other ideas. I hope that
>>soon I'll make it public - I want to verify results before doing so;
>>for now everything looks good (Rémi, if you want, I can send to you
>>current code - but I'm sure indexing schema will be changed before
>>final release).
>>
>>Eugene
>>
>>PS. I want to thank Ernst for discussions and his kind help in improving
>>indexing schema.
>
>I even found better ideas this morning that could improve indexing more (even
>more that what Ernst does). This consist in using more the fact that two Kings
>can not be on two adjacent squares :

You should probably be more careful with your public statements and re-read
my article because these ideas are already mentioned.

>Without pawns:
>
>33+58+58+58+
>   30+55+55+
>      30+55+
>         30
>
>= 404 possibilities (and not 462)

Sorry, but your math is wrong: 33 + 3*30 + 3*55 + 3*58 = 462.

>With pawns:
>
>60 58 58 58
>58 55 55 55
>58 55 55 55
>58 55 55 55
>58 55 55 55
>58 55 55 55
>58 55 55 55
>60 58 58 58
>
>= 1806 possibilities (and not 2016)

See Section 4.1 "The Two Kings" of my article. Because I confine the first
Pawn to one half of the board, I get 3612 = 2*1806 legal placements of two
Kings on an otherwise empty chess board.

For KPK you get 1806 * 48 = 86688 and I get 3612 * 24 = 86688 which is
exactly the same.

=Ernst=



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