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Subject: Re: Forced mate so solve...(proof number search)

Author: leonid

Date: 08:35:09 02/08/01

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On February 08, 2001 at 08:51:38, Dennis Breuker wrote:

>On February 07, 2001 at 21:11:50, leonid wrote:
>
>>On February 06, 2001 at 12:12:58, Angrim wrote:
>>
>>>On February 06, 2001 at 06:28:19, leonid wrote:
>>>
>>>>On February 06, 2001 at 02:57:32, Angrim wrote:
>>>>
>>>>>On February 05, 2001 at 07:23:58, leonid wrote:
>>>>>
>>>>>>Hi!
>>>>>>
>>>>>>If you like to solve forced mate position full of "depleted uranium"...
>>>>>>
>>>>>>[D]NKBN4/QRQ3rR/2Qb2r1/N1b1nb2/B2nbbbB/1RNqqqq1/8/2N2k2 b - -
>>>>>>
>>>>>>Please, indicate your result.
>>>>>>
>>>>>>Thanks,
>>>>>>Leonid.
>>>>>Useing proof number search, with no chess knowlege other than which
>>>>>moves are legal and the definition of checkmate, on an Athlon 650mhz:
>>>>>:proved that move c5xa7 wins, 15 turns
>>>>>:PN:402888 evals, 9241 expands, 56 max ply,  1.96 seconds
>>>>>
>>>>>not the shortest win, but at least its fairly quick.
>>>>>
>>>>>Angrim
>>>>
>>>>Hi!
>>>>
>>>>Can you give more detailed description of your search program? I am curious
>>>>since its base is probably identical to my mate solver. Mine use nothing more
>>>>but two parameters (not special value for each piece) that are legality of moves
>>>>and presence of check. It is everything that program need in order to find mate
>>>>or draw.
>>>>
>>>>Leonid.
>>>
>>>It uses a fairly generic proof number search, you might try searching
>>>for either "proof number search" or "pn-search" on the web, there are several
>>>papers on the topic available.  PN-search is a general tree proving algorithm
>>>that is domain independant, although it seems to do better for domains
>>>such as game tree searches where there is some concept of mobility being good.
>>>If you didn't recognise the name of the search method, it is fairly
>>>unlikely that you are useing it.
>>>Angrim
>>
>>Since you wrote about "pn-search" and "proof number search", I found already few
>>times those expressions used in few places. If you could in few words indicate
>>what those terms signify it will be of real help, at least me.
>
>See http://members.ams.chello.nl/dbreuker/thesis/index.html,
>and download chapter 3.
>
>Dennis (d.breuker@REMOVETHIS!chello.nl)
>
>>Thanks,
>>Leonid.

Thanks for link! I see now that it is not simple to explain, what it is, in few
words. Will go there at weekend to read.

Leonid.



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