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Subject: Re: One mate to solve for Champion!

Author: Angrim

Date: 00:45:49 06/18/01

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On June 17, 2001 at 16:55:53, Heiner Marxen wrote:

>On June 17, 2001 at 15:38:50, Angrim wrote:
>
>>On June 16, 2001 at 08:30:19, leonid wrote:
>>
>>>Hi!
>>>
>>>I am not sure how deep this position is but it look like that only strong
>>>program will find it easy.
>>>
>>>[D]3K4/1Q1Q1Q2/Q1R1R1Q1/2N1N3/Q1qBNqQ1/q1qBRq1q/brnq1nrb/3kq3 w - -
>>>
>>>Please indicate your result.
>>>
>>>Thanks,
>>>Leonid.
>>
>>This sure has a lot of transpositions possible!
>>I just added support for transpositions to my pn^2 code, and with the
>>new code my chess position solver handled this nice and fast, but the
>>old version took longer than I have patience for.
>>
>>new version:
>>proved that move e4xc3 wins, 13 turns
>>PN2:12688384 evals, 286977 expands, 79.30 seconds
>>
>>I halted the old version after 190m evals, 1363 seconds.
>
>Wow!  How interesting!
>
>From the thesis of Dennis Breuker I expect that adding transposition
>tables to PN^2 is not exactly trivial.
>Reading his thesis I have had several difficulties (some things look
>like plain wrong to me, but that can't be, so I just do not understand),
>and I would like to look at some working code, or see some pseudocode
>from someone with practical experience.
>
>So let me ask: what is the status of your code?  May we look at it?

My code is private, sorry.  However I would be glad to answer
questions about how pn^2 works.  I have spent a fair amount of
time on pn^2 since it is very handy for checking the safety of
openning lines in suicide chess.  I just had to plug in the
rules of chess to get a chess mate solver.

>Anyhow, thanks for sharing your results!
>Heiner

Angrim



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