Author: Paul
Date: 19:02:56 10/02/01
Go up one level in this thread
On October 02, 2001 at 20:00:24, leonid wrote:
>On October 02, 2001 at 10:07:56, Paul wrote:
>
>>On October 01, 2001 at 12:56:43, leonid wrote:
>>
>>>Hello!
>>>
>>>Today I wanted to put some simple mate position. This one, at least, have very
>>>unsophisticated shape.
>>>
>>>[D]8/8/3QQQQK/3nbrpn/3pQQBQ/3bQrqq/3qRqNB/3qRnNk w - -
>>>
>>>Please indicate your result.
>>>
>>>If you happened to have some version of Chess Master that do brute force search,
>>>please find for me time that it take for him to find mate in 4 and 5 moves for
>>>this position. I need this in order to have some idea what is his branching
>>>factor. I tried to do this myself with CM5000, that I have, but found no
>>>possibility to indicate my position. Since CM is the most performant and the
>>>most frequently mentioned program that solve the mate, I would like to know his
>>>basic mate solving capability.
>>>
>>>Thanks,
>>>Leonid.
>>
>>Hi!
>
>Hi!
>
>>Haven't got CM6000 installed at the moment, and don't remember if it's got a
>>mate level search, but John Merlino is the best person to answer that.
>>
>>For Pretz this is a difficult problem, for now it finds this:
>>
>>06:18 WM9 11 Nxh3 Ndxf6 Bxf3 Ng4+ Qfxg4 Bg7+ Qxg7 Rf6+ Qgxf6 Bxe4 Nxf2+ Qxf2
>>Nf4+ Bxf3 Qgxf3+ Qxf3 Qxf3#
>>20:52 WM8 11 Bxf3 Ndxf6 Bxg3 Ng4+ Qfxg4 Bg7+ Qxg7 Rf6+ Qgxf6 Nh2 Nf4+ Nxf3
>>Qgxh3+ Qh2 Qxh2#
>
>I am not sure what you found but mine looked only by selective. I don't know
>what is the minimal number of moves for this position. Mate by selective was
>found 10 move deep. It took pretty long time - 66 seconds.
Oh ... I didn't realize you couldn't read my output format, I'll explain:
<minutes:seconds> <evaluation> <ply> <principal variation>
06:18 WM9 11 Nxh3 Ndxf6 Bxf3 Ng4+ Qfxg4 ... Qxf3#
20:52 WM8 11 Bxf3 Ndxf6 Bxg3 Ng4+ Qfxg4 ... Qxh2#
The evaluation 'WM9' means 'W'hite 'M'ates in '9' moves, and WM8 ... you got it!
So Pretz first found a mate in 9, and after that on the same ply a mate in 8.
I checked later today without hash, just to be sure, and I think the mate in 8
is correct. Also tried some different settings that made everything quite a bit
faster (just over 2 minutes for the mate in 9), but found nothing shorter than a
mate in 8.
Maybe you can check with LLChess's brute force search? I started our Champion!
solver Chest on this problem a few minutes ago, but don't see a way to set the
size of the hash table(s) yet. The documentation mentions an -M switch, but
Chest doesn't seem to accept that in a DOS box under XP.
Hmmmm ... Heiner, hope you read this? It's now taking about 42MB of memory ...
started it like this: 'chest319 -b -Z8 x.epd'. Also tried -M350, but to no
avail.
Oh ... and I did not find a mate for black in this position, and neither did
Pretz. :)
Groetjes,
Paul
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