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Subject: Re: detecting result by evaluation in Kp vs K positions

Author: Mike Byrne

Date: 16:38:08 02/07/04

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On February 07, 2004 at 19:15:13, Dieter Buerssner wrote:

>On February 07, 2004 at 18:26:00, Uri Blass wrote:
>
>>I started to work on having some evaluation about endgame and
>>I wrote something to detect draws in KP vs K.
>
>If you have access to a good library, have a look at: Beal, D. F. and Clarke, M.
>R. B.; the construction of economical and correct algorithms for King and Pawn
>against King. Advances in Computer Chess 2, M. R. B. Clarke (ed.), pp. 1-30,
>Edinburgh University Press, 1980, ISBN 0-852-24377-4.
>
>>It does not detect every possible draw but at least hopefully when it detect
>>draw it is correct if I have no bugs.
>
>For testing such code, having access to Nalimov TBs can be very useful. Just
>write a small routine, that creates all possible KPK positions and compare the
>eval or your routine with the result of TB probing. I have done this for several
>routines in Yace. Especially, when you are going to use it for pruning, the
>knowledge should be perfect.
>
>>I read that yace is using bitbases even for 4 piece endgames when the bitbases
>>give only win draw loss information and I guess that the bitbases were
>>calculated from nalimov tablebases.
>
>Correct. However, the usage of bitbases is optional in general. For KPK I have a
>builtin bitbase. It needs (without many tricks) 24 kbyte (64*64*24*2/8). It is
>much easier to write a little program that puts out the table, than to write
>good kpk code "by knowledge".
>
>Regards,
>Dieter

Excellent idea -- how much space would KNBK, KRK, KQK and KBBK and  take.  I'm
thinking this would a nice feature in PDA's that do not use egtb's.



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