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Subject: Re: One easy mate to solve.

Author: leonid

Date: 04:55:30 11/16/01

Go up one level in this thread


On November 15, 2001 at 20:23:02, Heiner Marxen wrote:

>On November 15, 2001 at 12:05:46, Paul wrote:
>
>>On November 15, 2001 at 11:45:39, leonid wrote:
>>
>>>On November 15, 2001 at 09:44:55, Paul wrote:
>>>
>>>>On November 15, 2001 at 09:09:08, leonid wrote:
>>>>
>>>>>[D]2nkN3/2nqN3/2rrbb2/RBqQQqQQ/RBqNPqPQ/2qpqp2/3B4/3K4 w - -
>>>>>
>>>>>Please indicate your result.
>>>>>
>>>>>Thanks,
>>>>>Leonid.
>>>>
>>>>Hi Leonid,
>>>
>>>Hi!
>>>
>>>>Haha! .. that was a surprise when I saw what Pretz came up with:
>>>>
>>>>1. Nexc6+ Qcxc6 2. Qgxf6+ Qxf6 3. Qexf6+ Qxf6 4. Qxf6+ Qe7 5. Qxe7+ Nxe7 6.
>>>>Nxe6+ Nxe6 7. Ra8+ Nc8 8. Rxc8+ Kxc8 9. Nxd6+ Kd8 10. Ra8+ Qxa8 11. Qxa8+ Qc8
>>>>12. Qe8+ Kc7 13. Qexc8+ Kb6 14. Qa5#
>>>>
>>>>So a mate in 14! I think I must have a bug ...
>>>
>>>I don't think so. It is mate in 13. Verified it 12 moves deep by brute force to
>>>be sure. Easy branching factor. Found mate in 13 by selective. Your, probably,
>>>went just one move deper to find its mate. Good result.
>>
>>Just after I posted my message mine also found a mate in 13 ... I was just too
>>quick, but I had to laugh out loud because I know you don't post mates over 13
>>moves deep! I thought maybe you had changed your solver.
>>
>>>I see that you have almost no competition here. Your selective look like to be
>>>very effective. I still hope that somebody will come with Chess Master solution
>>>to see better your and mine position.
>>>
>>>What was your time here?
>>
>>07:28 WM13 13 Nexc6+ Qcxc6 Qgxf6+ Qxf6 Qexf6+ Qxf6 Qxf6+ Ne7 Ra8+ Nxa8 Rxa8+
>>Qxa8 Qxa8+ Qcc8 Ba5+ Qcc7 Bxc7+ Qxc7 Nxe6+ Rxe6 Qhd5+ Rd6 Qfxd6+ Qxd6 Qxd6#
>>
>>So no bug, mine just took the long way home first ...
>
>Hi,
>
>Chest confirms the above: #13 with a unique key move:
>
>PV: Nexc6+ Qcxc6 Qgxf6+ Qxf6 Qhxf6+ Qxf6 Qxf6+ Qe7 Qxe7+ Nxe7 Nxe6+ Nxe6 Ra8+
>Nc8 Rxc8+ Kxc8 Nxd6+ Kd8 Nxc4+ Qxd5 Qxd5+ Kc8 Ba6+ Kb8 Qb7#
>
>(K7/600, 30MB hash, 57.2 minutes)
>#  1      0.00s                 0kN           0.87          1-         0
>#  2      0.00s                 0kN           1.00          1-         0
>#  3      0.01s                 0kN [  7.42]  0.92         63-         0
>#  4      0.03s [  3.00]        2kN [  3.71]  1.12        190-         0
>#  5      0.09s [  3.00]        6kN [  3.29]  1.53        348-         0
>#  6      0.25s [  2.78]       18kN [  3.12]  2.03        861-         0
>#  7      0.83s [  3.32]       63kN [  3.43]  2.51       2897-         0
>#  8      1.98s [  2.39]      155kN [  2.46]  3.12       6827-         0
>#  9      6.11s [  3.09]      489kN [  3.17]  3.69      22121-         0
># 10     23.47s [  3.84]     1850kN [  3.78]  3.87     100289-         1
># 11    112.24s [  4.78]     8475kN [  4.58]  4.60     516316-      6868
># 12    501.96s [  4.47]    31935kN [  3.77]  4.53    3036282-   2249851
># 13   3434.74s [  6.84]   208426kN [  6.53]  4.69   20984850-  20198419
>
>>>Mine by brute force took 1 hour and 50 min for 12 moves to say "No". Selective
>>>in 13, took 9 seconds.
>>
>>That's pretty fast ... :)
>
>... but not yet optimal :-))

Hi, Heiner!

It was very interesting for me in this position see your and mine program do
work without hash on the same computer. Everything went actually in almost twin
brothers indentical way. Your had only advantage in branching factor just after
9 move. When mine was already 11.6 between 11 and 12 move, your was still very
stable and around 5. Time for 12 moves was practially the same considering 12
move depth. Mine 1 hour and 49 min and your 3h 54 min. Considering that my
program is done on Assembler your went just slightly better that mine.

My time was:

Depth in moves         Time        Branching factor.     NPS

4 moves                0,05 sec
                                   2
5 moves                0.10 sec                          44k
                                   2.8
6 moves                0.27 sec                          39k
                                   2.8
7 moves                0.769 sec                         42k
                                   2.64
8 moves                2.03 sec                          57k
                                   4.16
9 moves                8.46 sec                          74k
                                   6.4
10 moves               54.78 sec                         101k
                                   10.5
11 moves               9 min 27 sec                      116k
                                   11.6
12 moves               1 h 49 min 32 sec                 118k

Cheers,
Leonid.

>Cheers,
>Heiner



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