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Subject: Re: One mate to solve... that now is very easy.

Author: Heiner Marxen

Date: 05:42:34 05/07/01

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On May 07, 2001 at 03:44:07, Paul wrote:

>On May 07, 2001 at 03:18:23, Paul Byrne wrote:
>
>[D]Qqrkrq1Q/1QqqqqQ1/qBbnnbBq/1NQ2QN1/8/2Q2Q2/3RR3/3K4 w - -
>
>>G2K's PN search says:
>>
>>1W. i=8094 n=324622 p=0 d=1000000000 t=3.620
>>1W. Qxc7 wins!
>>
>>3.62 seconds, 324633 nodes.  This is the kind of mate PN does well in, although
>>it doesn't get you a mate-in-n number.
>
>Hi Mr. Byrne,
>
>I (still) haven't read anything about PN, but am very interested to learn ... is
>there anything you can recommend for reading? The only thing I have is a
>postscript doc by Victor Allis, that I think is about the subject (haven't got a
>reader installed now), but maybe you know of something shorter/lighter to get
>into it?

Sorry for stepping in, again.

The Allis article is most probably a good introduction to PN search.

Postscript is a quite common document form in the scientific community.
Practically every laser printer does understand it (without further
software support).  I recommend to find a solution for that.
Otherwise, find a friend with a Linux system, which has ghostscript by
default, the GNU postscript viewer.

I have the dissertation of Dennis M. Breuker from 1998, "Memory versus Search
in Games" (got it from the web somewhere).  It is 170 pages postscript,
but also is a quite complete and up to date discussion of PN search,
and a modified version PN^2 search.  It contains examples and pseudo code.
For me it was a good reading.

Where it introduces PN search, it states that that chapter is an adapted
version of: D.M.Breuker, L.V.Allis & H.J. van den Herik: "How to Mate:
Applying Proof-Number Search", Advances in Computer Chess 7, pp 251-272,
University of Limburg, Maastricht, The Netherlands.
You could try to get this one e.g. in a University library.

A quick google search turns up: http://www.cs.vu.nl/~victor/thesis.html
a book by L. Victor Allis: "Searching for Solutions in Games and Artificial
Intelligence", obviously his thesis.  Appears to be downloadable as postscript.

Hope that helps.
Heiner


>I understand from a remark by Heiner Marxen that you have to have plenty of
>memory for PN search, presumably coz the search results have to be saved? But
>why don't you have a winning variation (pv) and number then?
>
>>>>[D]nqrkrqn1/1QqnnqQ1/1BnbbnB1/BQNNNNQB/8/8/3RR3/3KQ3 w - -
>
>>And on this one,
>>
>>1W. i=255976 n=8485323 p=0 d=1000000000 t=76.740
>>1W. Bxc7 wins!
>>
>>Which is interesting.  I think the first one was the easy one.  :)
>>The non-checking move in there gives PN search a tough time.
>>
>>Thanks for the interesting problems...
>>-paul [the other one  :)]
>
>Yeah, it's a bit confusing, should maybe ask Steve to change my name ... but
>it's nice to come into a forum and hear people whisper: "Hey, there's Paul!". ;)
>
>>By the way, the second one is also a win in ICC's wild 17.  Forgot to switch
>>variants on my first attempt...
>
>Paul (the neutrally charged one :)



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