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Subject: Re: ICC wild 7

Author: Dieter Buerssner

Date: 10:25:20 02/02/05

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If anybody with a rather big machine wants to solve this fast, one idea. Use two
hash tables - one for the pawn endgame positions and one normal. Actually, the
first one would not be a hash table at all, but more like a TB. About 2 GB of
memory would be enough. As long as we have a pawn endgame (or when we have one
again after perhaps a small intermezzo with a Q endgame) we can index all
possible positions. We have 6 files with pawns. On each file, there can only be
one pawn or none. So each file has 7 possible states (pawn on 2nd row, 3rd, ...
7th, no pawn). There are 3612 legal KK positions, so all pawn endgames need

3612 * 7^^6 = 4.2xe8

A move can be stored in 1 byte (for these positions) easily. Score->2 bytes. 1
byte depth. This is less than 2 GB then. Remaining RAM can be used for the
normal HT. One would only store white to move positions. For black to move,
rotate the board by 180 degrees and switch white to black.

Equipped with this, I'd try a search with infinite extensions while the position
is a pawn endgame. Perhaps 2 bounds are needed - then 2 GB would not be enough,
and some expensive hardware would be needed (I think).

Regards,
Dieter



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