Author: Heiner Marxen
Date: 18:06:28 10/03/01
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On October 03, 2001 at 15:43:57, Paul wrote: >On October 03, 2001 at 11:53:39, Heiner Marxen wrote: > >>On October 02, 2001 at 09:52:50, Paul wrote: >> >>>On October 02, 2001 at 08:41:20, leonid wrote: >>> >>>>[D]kq4BK/pq4QQ/2qq1P2/1NnqBnN1/3PpP2/2P2r2/RQ4qr/RQ4bb w - - >>>> >>>>I have said that this position is for "Champions" only having in mind that some >>>>people will try to solve it by brute force. Brute force is the only way to know >>>>minimal nomber of moves that lead to mate. But it could be not all the time >>>>easy. When I tried this position on two professional program, I was impressed. >>>>On Celeron 600Mhz, and with 1M of hash, one expected to solve position in around >>>>4000 years. Other, with no hash, after around 11000000000 years of thinking >>>>expected to recognize shortest mate. >>>> >>>>Please indicate your result. >>>> >>>>Thanks, >>>>Leonid. >>> >>>Hi Leonid, >>> >>>I just now started to look at both your positions, the simple one from yesterday >>>and this one, and I think you have a bit of a twisted nomenclature! >>> >>>This one is the simple one, the other one is more difficult. Even if this one >>>seems to be a mate in 12, and the other in 9. But maybe that's only the case for >>>Pretz, I'm curious about LLchess. >>> >>>For this one I find a mate in 12 in 3 seconds by applying some gentle force: >>> >>>00:03 WM12 12 Rxa7+ Q8xa7 Rxa7+ Kb8 Rxb7+ Nxb7 Qf8+ Qc8 Qxc8+ Kxc8 Nxd6+ Nfxd6 >>>Be6+ Kd8 Qb6+ Ke8 Bd7+ Kf8 Bxd6+ Nxd6 Qb8+ Nc8 Qxc8# >> >>Hi Leonid, Hi Paul! >> >>Since 1BELCT has finished, and my PC is reassembled, its time for a mate... :-) > >Heiner, read you had a crash, sorry 'bout that ... but, I'd be happy to send you >all of Leonid's previous problems, so you can run them again ... ;0 Due to some kind of magic the crashed disk started to work again :-) Really. I cannot explain. It's just a fact. Nearly no data was lost. Thanks for your offer, but I have enough of Leonids problems. Someone should make a web page from them... :-) >>Chest confirms the above: Rxa7+ is the only key move for the shortest >>solution. It gives nearly the same PV: >> >>PV: Rxa7+ Q8xa7 Rxa7+ Kb8 Rxb7+ Nxb7 Qf8+ Qc8 Qxc8+ Kxc8 Nxd6+ Nfxd6 Be6+ Kd8 >>Qb6+ Ke8 Bd7+ Kf8 Bxd6+ Qxd6 Qxd6+ Nxd6 Ne6# >> >>(9.5 minutes on a K7/600 with 350 MB hash). >> >>Heiner > >Just for comparison: with the command 'chest319 -Z12 -b x.epd' in a DOS box >under Windows XP it took about 5'45" on my p3/1000. That's a linear speedup, >although I used probably only ~40MB hash Well, that job generated only ca 160 MB contents, so 350 MB was more than it used, and 40 MB are not overrun that much. No surprise that speedup is still quite linear. The size of the L1/L2 caches could also be significant, but I lack the relevant data. >(that's default, don't know how to set >hash in Chest, any tips?). See: http://www.icdchess.com/forums/1/message.shtml?191646 >Paul Cheers, Heiner
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