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Subject: Re: Try to solve mate.

Author: Heiner Marxen

Date: 05:47:29 09/16/02

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On September 14, 2002 at 19:39:32, leonid wrote:

>On September 14, 2002 at 16:58:23, Heiner Marxen wrote:
>
>>On September 14, 2002 at 10:44:49, leonid wrote:
>>
>>>On September 14, 2002 at 10:14:52, Paul wrote:
>>>
>>>>On September 14, 2002 at 09:47:21, leonid wrote:
>>>>
>>>>>On September 14, 2002 at 09:26:25, leonid wrote:
>>>>>
>>>>>>On September 14, 2002 at 08:51:31, Paul wrote:
>>>>>>
>>>>>>>On September 14, 2002 at 07:55:35, leonid wrote:

>>>>>>>>Still, maybe, You will be tempted for something more heavy and I this way will
>>>>>>>>be able to find more on this position:
>>>>>>>>
>>>>>>>>[D]2qRQq2/p6P/q1BqqR1N/r6B/n1QNQQ1B/r6k/b1QKNP1q/bq4qn w - -
>>>>>>>>
>>>>>>>>On description of this mate I can see that it was solved by selective in 13
>>>>>>>>moves but brute force search went not up to the end in order to find shortest
>>>>>>>>move. Brute force search, without finding any mate, went only 9 moves deep.
>>>>>>>
>>>>>>>This one was indeed a lot more difficult, mine didn't fare so well here:
>>>>>>>
>>>>>>>06:49 WM11 07 Q8xe6+ Qdxe6 Qff3+ Rxf3 Qxf3+ Kxh4 Nhf5+ Rxf5 Nxf5+ ...
>>>>>>>
>>>>>>>So it found a mate in 11 in almost 7 minutes, with an incomplete pv ... these
>>>>>>>d#*&#@rned hashtables ;) ... will have to think about this ... any tips anyone?
>>>>>>>
>>>>>>>>Please indicate Your result.
>>>>>>>>
>>>>>>>>Thanks,
>>>>>>>>Leonid.
>>>>>>>
>>>>>>>Thanks for your mates as usual ...
>>>>>>
>>>>>>Thanks, Paul!
>>>>>>
>>>>>>Now I can see that second one is no far then 11 moves. I  can even put this
>>>>>>position at 10 moves by brute force for night. If braching factor will not
>>>>>>suddenly jump, then it should be enough time for me for finding its depth.
>>>>>>
>>>>>>First position have excellent time!
>>>>>>
>>>>>>Mine, on usual setting, found mate in 1.75 sec.
>>>>>>
>>>>>>Cheers,
>>>>>>Leonid.
>>>>>
>>>>>Paul, just after writing my message, I started to see second position in my file
>>>>>to indicate 11 moves. When I finally found it (I not indicate before on what
>>>>>page I had it), I looked that it was in reality solved by selected in 11 moves,
>>>>>just as You said. Before upper part of page was covered with page keeper and it
>>>>>is how I missed some additional description. If I knew this yesterday, when I
>>>>>found this position, I could put search for 10 moves by brute force at night.
>>>>
>>>>Hey!! ... so you tricked us ... that's not fair ... I would have found it much
>>>>faster if I'd known! ... just kiddin' ... :)
>>>
>>>I was actually tricked by myself. I did expected that this position was very
>>>difficult since I could see that it was solved by very slow selective and only
>>>at 13 moves. 13 moves at large default setting (I use it before searching by
>>>much easier solution) took 13.5 minutes to solve. When I looked into 11 moves
>>>selective solution its paramether indicated that solution was almost simple.
>>>
>>>
>>>>>Selective in 11 moves was solved in 18 seconds. Usual setting.
>>>>
>>>>Not bad at all ... you really should implement hash to get a bit faster though
>>>>... ;)
>>
>>Chest is still running for depth 11, but after 3478 secs has already reported
>>that there is no mate in 10.  So, we are already sure, that 11 is minimal
>>depth.
>
>Paul just said to me that there are no mate in 10.
>
>>#  4      0.09s                17kN [ 10.28]  1.07        737-         0
>>#  5      0.96s [ 10.67]      137kN [  7.88]  1.21       8654-         0
>>#  6      6.32s [  6.58]      791kN [  5.79]  1.49      66512-         0
>>#  7     31.30s [  4.95]     3675kN [  4.65]  2.11     351756-         0
>>#  8    143.98s [  4.60]    16349kN [  4.45]  2.73    1718242-      7352
>>#  9    668.36s [  4.64]    73337kN [  4.49]  3.46    8452143-   5252957
>># 10   3477.74s [  5.20]   373030kN [  5.09]  4.02   45004182-  41804949

Chest completed its job:
# 11  16881.61s [  4.85]  1819969kN [  4.88]  4.43  226032315- 222833082

PV: Q8xe6+ Qdxe6 Qff3+ Rxf3 Qxf3+ Qgg3 Nf4+ Kxh4 Qxg3+ Qxg3 Nf3+ Qxf3 Ng2+ Kh3
Qh4+ Kxg2 Bhxf3+ Kg1 Qxh1+ Kxf2 Qg2#

 Q8xe6+ Qdxe6 Qff3+  Rxf3  Qxf3+ ...+8
                     Qhg3  Nf4+  ...+3
                     -*-   Nf4+  ...+2
        Qcxe6 Nxg1+  Qbxg1 Qef5+ ...+5
                     Qhxg1 Bg4+  ...+5
        Rf5   Bg4+   Kxh4  Nxf5#
                     Qxg4  Qxg4#
        Qg4   Qfxg4#

I.e. the key move is unique, and Chest needed 4.9 hours.

Cheers,
Heiner




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

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