Author: Paul
Date: 07:19:30 10/02/01
Go up one level in this thread
On October 02, 2001 at 10:05:25, leonid 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, > >Hi, Paul! >> >>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 > >It is mate in 12 for sure. I solved this mate by brute force in 44 minutes. 11 >moves took 45 minutes to say that it have no mate. > >This position is more simple that previos and this is the reason why mine was >able to see it all 12 moves deep. > > >>Pretz, I'm curious about LLchess. >> >>For this one I find a mate in 12 in 3 seconds by applying some gentle force: > >Excellent! I see that your work great. When program can see so deep without any >mistake it is a real sign that it is basically solid. > >My selective found mate in 12 moves in 0.16 sec. That's a great time, Leonid! Your use of assembler and choice of move ordering and move selection mean a lot when mate solving. I still use a search and move order that is usual in other amateur chess programs. I also don't use any special ply routines, all plies are handled equal. Will have to try checking moves first one of these days. Groetjes, Paul >>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# >> >>With colors switched it's a mate in 2 ... ;) > >Yes. Since it is very short I even not indicated it. Since your last finding >(very good one) I try to not miss to verify for the opposit side, even if I >think that other side had no chance or have very short mate. > >Cheers, >Leonid.
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