Author: Heiner Marxen
Date: 18:41:00 05/02/01
Go up one level in this thread
On May 02, 2001 at 20:12:09, leonid wrote:
>On May 02, 2001 at 16:24:15, Paul wrote:
>
>>On May 02, 2001 at 16:15:41, leonid wrote:
>>
>>>On May 02, 2001 at 12:54:56, Paul wrote:
>>>
>>>>On May 02, 2001 at 11:58:03, leonid wrote:
>>>>
>>>>>Hi!
>>>>>
>>>>>If you want to solve some mate that is completely moderate, then this is one.
>>>>>Position is not very simple but have nothing of deep or complicated. It stay
>>>>>just in middle.
>>>>>
>>>>>[D]qQR1qQrk/1r1qQqqn/3N1nbn/1Q2qQNR/3Q4/bq3q2/QBB2Q1Q/K7 w - -
>>>>>
>>>>>Please indicate your result.
>>>>>
>>>>>Thanks,
>>>>>Leonid.
>>>>
>>>>Hi guys!
>>>>
>>>>Pretz just found a mate in 10 ...
>>>>
>>>>10:36 WM10 09 Ndxf7+ Bxf7 Nxf7+ Qbxf7 Qxg8+ Qfxg8 Qxg8+ Qgxg8 Qfxf6+ Qfxf6
>>>>Qfxf6+ Qxf6 Qdxf6+ Nxf6 Bxf6+ Qg7 Rxe8+ Qxe8 Q5xe8#
>>>>
>>>>Could become shorter with longer thinking time though ...
>>>
>>>Hi!
>>>
>>>And by what way you found 10 moves deep? By brute force (perfect search that see
>>>everything) or selective (quick)?
>>>
>>>Salut,
>>>Leonid.
>>
>>I only have a selective search ... so that's what I used this time. :)
>>
>>Well ... of course I can switch off nullmove, all extensions ... etc, but that
>>really won't cut it. You need some clever stuff to make a frute force search
>>fast, and I haven't got that ... but that's what we've got Heiner for. ;)
>
>I asked you this because I expected that this time you went by brute force since
>this position is 10 moves deep. So, your result is 100% right. You have good
>program!
>
>This position happened to have very accessible branching factor for brute force.
>To my surprise, it took only 38 min 25 sec to say that mate in 9 do not existe.
>With hash at work it could be even shorter.
>
>I solved this position, just like you, by 10 moves selective search.
Hi pals,
Chest happens to agree completely. In 51.6 mins (K7/600, 350MB) it detects
two solution moves for a mate in 10. So Pretz is not as bad as you
expected, Paul ;-) It has quite a good hit rate! Here are 2 PVs:
Ndxf7+ Bxf7 Nxf7+ Qbxf7 Qxg8+ Kxg8 Rxe8+ Qxe8 Qxh7+ Nxh7 Q5xe8+ Nf8
Q8xf8+ Qxf8 Rg5+ Kh8 Qxh6+ Qh7 Qhxh7#
Ngxf7+ Bxf7 Nxf7+ Qbxf7 Qxg8+ Kxg8 Rxe8+ Qxe8 Qxh7+ Nxh7 Q5xe8+ Nf8
Q8xf8+ Qxf8 Rg5+ Kh8 Qxh6+ Qh7 Qhxh7#
Again, they are basically equal. Captures over captures.
Timing info:
# 1 0.00 0.87 1- 0
# 2 0.00 1.00 1- 0
# 3 0.03 0.94 111- 0
# 4 0.16 1.06 782- 0
# 5 0.58 1.31 2513- 0
# 6 3.01 1.40 14280- 0
# 7 16.35 1.71 81503- 0
# 8 86.06 2.04 431966- 0
# 9 553.16 2.38 2589797- 316
# 10 3098.17 2.79 13605811- 4908464
Again, lots of mate-in-one in the opposite direction: 12.5%.
CU,
Heiner
>Paul, do you have, by accident, Web address of Genius 2 ("free Uri's version).
>Something happened to mine when I wanted to see this position on Genius 2. I use
>Genius 2 (Genius 4 I have) because I remember that it was without any bugs in
>mate solving and because Rebel 10 have limit of 100 moves. Meantime, will try to
>see if address is still here in Chess Club old pages.
>
>Salut,
>Leonid.
>
>
>>Groetjes,
>>Paul
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