Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: If you want solve one mate...

Author: Heiner Marxen

Date: 12:22:30 01/21/01

Go up one level in this thread


On January 21, 2001 at 14:13:30, leonid wrote:

>On January 21, 2001 at 13:44:00, Heiner Marxen wrote:
>
>>On January 21, 2001 at 13:16:22, leonid wrote:
>>
>>>On January 21, 2001 at 12:43:34, Heiner Marxen wrote:
>>>
>>>>On January 21, 2001 at 11:56:09, leonid wrote:
>>>>
>>>>>Hi!
>>>>>
>>>>>This mate position is very handy when you want to check the limits in your
>>>>>program. It is amusing also. Number of legal moves for both sides is slightly
>>>>>over one hundred.
>>>>>
>>>>> knq3q1/rq1q1qbQ/Qq2Q3/1Qn1Q2B/Q1qN1Q1r/4K1B1/1q4QR/1N1q3Q white to go.
>>>>
>>>>A hint to you, Leonid:  if you like to see a diagram for the notation above:
>>>>(1) Stick a [D] directly before the FEN string,
>>>>(2) append (blank seperated) colour to move, i.e. b or w
>>>>(3) append (blank seperated) castling rights: - for nothing, KQkq or part
>>>>    of it for white/black king side/queen side
>>>>(4) append (blank seperated) e.p. info: - for "no e.p. possible"
>>>>You can look up the details in the FEN standard, part of the PGN standard.
>>>>Look at the line below, which I typed in, and see the diagram, provided not
>>>>by me, but by the CCC web server, which recognizes the [D] and FEN after it,
>>>>and inserts the graphics.  You can do that also.
>>>
>>>Thanks! Will try to use it the next time.
>>>
>>>Leonid.
>>>
>>>
>>>>[D]knq3q1/rq1q1qbQ/Qq2Q3/1Qn1Q2B/Q1qN1Q1r/4K1B1/1q4QR/1N1q3Q w - -
>>>>
>>>>Chest says "no mate in 9" (216 seconds, K7/600 335MB hash).
>>>>I will ask for more depth...
>>>
>>>Are there no mistake? You have really 335Mb hash?
>>
>>Yes!  :-)
>>I bought 512 MB.  Was a bit expensive, but my monitor costs even more.
>>And on work I have seen what 512MB can do to big Chest jobs, so I really
>>wanted to have so much memory.  I like it :-)
>
>And what the monitor you have? 21 inch?
>
>The last time, around 3 months ago, I bought my last 17 inch. Very cheap and
>very good. My next dream is new computer. I need it for my programming.

It is a 15.1 inch TFT screen.  It had to fit into this tiny room, where
my computer is placed.  I am very satisfied with it, but it is not cheap.

>>>216 sec for 9 moves like very good. I went, by brute force, only up to 7 moves.
>>>It was already 2 min. 19 sec. But for this position, which look very heavy,
>>>branching factor was very normal. Like what you can expect from usual forced
>>>mate position.
>>>
>>>4 moves - 0.77 sec
>>>               branching factor 5.8
>>>5 moves - 4.39 sec
>>>                                5.3
>>>6 moves - 23.02 sec
>>>                                6.1
>>>7 moves - 2 min 19 sec
>>
>>Yes, black has also 9 queens, and whites king is exposed.  If white does
>>anything not really forcing, black will start to force, or even mate.
>>Therefore the search trees can be small in many branches.  In 17% of all
>>considered cases, black mates white!  (yes, Chest tries that sometimes)
>>
>>Here are my numbers:
>>
>>#  1      0.00  0.87          1-         0
>>#  2      0.01  1.00          1-         0
>>#  3      0.03  0.96        107-         0
>>#  4      0.19  1.04        819-         0
>>#  5      0.87  1.23       4167-         0
>>#  6      3.73  1.48      17787-         0
>>#  7     14.90  1.79      72503-         0
>>#  8     56.43  2.17     290160-         0
>>#  9    213.00  2.57    1142162-         0
>># 10    831.85  2.90    4544295-     16385
>>(depth  seconds speed   node in   node out
>
>Pretty good branching factor!

Yes, and here is the next line:
# 11   3686.85  2.90   20110217-  11363105

Chest does not find any mate in 11.

>>>Leonid.
>>>
>>>>Heiner
>>>>
>>>>>If you will solve, it will be nice if you will indicate your result.
>>
>>
>>Is there any forced solution, at all?  Depth=11 will take around an hour,
>>and I will not go much further, if there is no real chance.
>
>For 11 moves I don't know. My solved it by selective only at 12. Actually, this
>position is more that strange. Solution was found by the most easy level in
>selective search. Because of very good for me branching factor, I expected it
>will be instant. It was not so. It took 2 seconds.
>
>Leonid.

Fine, so I stop this, now.  Looks like there is no shorter mate,
which is not surprising for a position like this one.

I just asked crafty 17.7 for a depth=1 analysis, and even after 3 minutes
I still see no output ;-)  Obviously the quiescence search is exploding.

Can you give some PV for the forced #12 line?  Just curious.

Heiner



This page took 0.02 seconds to execute

Last modified: Thu, 07 Jul 11 08:48:38 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.