An Evaluation Mystery ?

Discussion of chess software programming and technical issues.

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Pio
Posts: 334
Joined: Sat Feb 25, 2012 10:42 pm
Location: Stockholm

Re: An Evaluation Mystery ?

Post by Pio »

Hi Evert!

Why not try to implement my idea given here
http://www.talkchess.com/forum/viewtop ... 97&t=42677. That would lead you to search a much smaller tree hopefully :)

Good luck!

Kind regards
Pio
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hgm
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Joined: Fri Mar 10, 2006 10:06 am
Location: Amsterdam
Full name: H G Muller

Re: An Evaluation Mystery ?

Post by hgm »

Evert wrote:Well, positions where a piece outright hangs are about 10%, off the top of my head (I can check to make sure).
No way. They are like that against a bare King, which on average attacks 6.6 squares. A Rook covers 14 squares, which is more than 20% of the board in addition. Chances that the Bishop is protected are only ~10%. So there is something like a 30% chance on a hanging Bishop, and a 33% chance on a hanging King, You might not count the latter as part of the total, but that would reduce the total by so much that 45% of it would ow have a hanging Bishop.
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Evert
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Location: NL

Re: An Evaluation Mystery ?

Post by Evert »

You're right, I mis-remembered the numbers.

The rook hangs in ~15% of the positions (in ~1% of positions it is pinned), and this is what I remembered. The bishop actually hangs in ~65% of won positions and can be won by a skewer in ~18% of positions.