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Subject: Re: Using just Upperbounds and Lowerbounds

Author: Dan Newman

Date: 01:38:40 02/05/01

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On February 04, 2001 at 17:08:07, Alvaro Jose Povoa Cardoso wrote:

>I think I found the big problem with my program:
>I don't store captures in the hashtable, so it is impossible to retrieve a long
>PV from it (life can be cruel).
>I do that because captures can be a real pain in the neck to store.
>A king (dama in the portuguese version of checkers) can make multiple captures
>(6-9 max).
>A normal move can be something like  '30-16', but how do I store a capture like
>'3x17x26x19x32' in the hash table?
>Can someone give me an hint?
>
>Thank you
>Alvaro Cardoso

Assuming captures are made only by jumping diagonally (like in checkers in
the US), then you only have 4 different directions that you capture in:
NE, NW, SE, and SW.  That means you can encode a capture sequence as a
series of 2-bit codes: NE=00, NW=01, SE=10, SW=11.  With 9 max captures
this takes 18 bits.  You also need a 4 bit count of the captures so you
know where the end of the sequence is.  Total for the capture sequence:
22 bits.

-Dan.



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