Author: Heiner Marxen
Date: 09:34:19 05/01/01
Go up one level in this thread
On May 01, 2001 at 07:55:26, leonid wrote: >On May 01, 2001 at 01:02:33, Paul Byrne wrote: > >>On April 29, 2001 at 07:32:15, leonid wrote: >> >>>Hello! >>> >>>I know that I should never indicate here any position like this, but it is just >>>too seductive! Only really dedicated man or highly performant mate solver can >>>crunch it. >>> >>>[D]Qrbqkbr1/Qn3qPP/NQqQq1nB/1qNqQBq1/1Qq1q2Q/8/3RR3/4K3 w - - >>> >>>Please indicate your result. >>> >>>Thanks, >>>Leonid. >> >>That was a tough one! My PN search went through 512MB of memory without solving >>it. PN2 got Qbxd8+ winning in 1316.46 seconds (100043829 nodes) -- the PN2 code > >Hi, Paul! > >What is PN2? I strongly suspect it is a modified version of "proof number search". I seem to remember that Aske Plaat wrote about it. You should find something with your favorite search engine (e.g. Google). >Your move is what mine found. > >Your solution was quick compared with mine. I actually had the impression that >this position contain the mate and asked to search this position. Very deep >selective search, 13 moves deep. Left my solver thinking in the night. Celeron >600Mhz. No hash. It took almost 4 hours (3 h 56 min) to solve in 13 moves. But >at what depth your found? Maybe your said that mate existe in 12 or even 11. > >Cheers, >Leonid. Hi Leonid, According to Chest it is a mate in 13, i.e. no solution in 12 or less moves. On a K7/600 with 350 MB hash Chest spends nearly 37 hours to find that there are two key moves for the mate in 13: Qdxd8+ and Qbxd8+. I have not yet a PV (the solution tree is not contained in the hash, any more, and is currently recomputed). I will follow-up when it is there. Here is the timing statistics: depth time[s] speed nodes in nodes out # 1 0.00 0.94 1- 0 # 2 0.01 1.00 1- 0 # 3 0.03 0.97 88- 0 # 4 0.20 1.12 612- 0 # 5 1.06 1.31 3484- 0 # 6 4.64 1.66 16340- 0 # 7 17.77 3.27 67644- 0 # 8 79.58 5.29 335490- 0 # 9 385.99 7.30 1776286- 30 # 10 1492.82 9.43 7245314- 342027 # 11 5287.27 11.55 28318639- 19570743 # 12 31346.51 10.79 174568973- 165821072 # 13 132724.97 10.18 765545533- 756797632 Cheers, Heiner >>is set up for suicide chess though and could probably be sped up a good bit for >>regular chess. >> >>-paul
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