Author: leonid
Date: 15:35:08 05/05/01
Go up one level in this thread
On May 05, 2001 at 12:08:53, Heiner Marxen wrote: >On May 04, 2001 at 17:09:35, Heiner Marxen wrote: > >>On May 04, 2001 at 16:05:36, leonid wrote: >> >>>On May 04, 2001 at 15:38:23, Angrim wrote: >>> >>>>On May 04, 2001 at 10:26:02, leonid wrote: >>>> >>>>>Hello! >>>>> >>>>>Had bad lack this midnight when one call came from my work. It took me 20 >>>>>minutes to do it but I went to my bed only at 2 o'clock. One good result from >>>>>broken sleep was this position that you can try to solve. It probably will >>>>>demand one sleepless night from your program, if you will insist on shortest >>>>>mate. >>>>> >>>>>[D]RnqkqnR1/qBNbNBq1/QqQqQqQ1/BrQqQrB1/3q4/8/3Q4/3K4 w- - >>>>> >>>>>Please indicate your result. >>>>> >>>>>Thanks, >>>>>Leonid. >>>> >>>>this one IS tough, >> >>Chest agrees: there is no mate in 12, as found in 2.1 hours (K7/600, 350MB). >> >>>> wonder if having endgame tables would help a lot? >>> >>>Never! >> >>:-) :-) >> >>There are 16+15 = 31 men on the board. A mate in 12 is 23 plies deep, >>so we are left with 31-23 = 8 men at least for a terminal position in >>such a search. You have to go some moves deeper before there is a chance >>that 6-piece tables may help. >> >> >>>>I'll leave my proof number searcher running while I'm at work, maybe it >>>>will find an answer in a few hours.. currently its obsessing over Qxd7. >>> >>>Everything depend on each program branching factor. Two professional that I >>>tried until now (they are not specialized in solving mate nut never hung on you) >>>were slow. The every next program could have very good branching factor for this >>>position. I had the chance to see very good on mine, mainly for brute force. >>>Selective was slow. It took this in 10 min 42 sec. Celeron 600Mhz. No hash. >>> >>>Leonid. > >Chest has just completed depth=13. There are two key moves for the mate >in 13: Qexd7+ and Qcxd7+. Here are the PVs: > >Qcxd7+ Qexd7 Rxf8+ Qxf8 Qxd7+ Qcxd7 Ne6+ Q5xe6 Bxb6+ Rxb6 Qaxb6+ Qaxb6 >Rxb8+ Qxb8 Nc6+ Qbxc6 Qgxf6+ Rxf6 Qxb8+ Qcc8 Qxf8+ Qde8 Qxd4+ Qd7 Bxf6# > >Qexd7+ Qcxd7 Ne6+ Kxe7 Nxd4+ Rxe5 Bxf6+ Qxf6 Qxf6+ Kxf6 Qh6+ Ke7 >Qxd7+ Nfxd7 Rxe8+ Kxf7 Bxd5+ Rxd5 Re7+ Kxe7 Qg7+ Ke8 Qcc8+ Qd8 Qxd8# > >On K7/600 (350 MB hash) it took 11.7 hours to find both key moves, and 15.3 >hours total time to also print a solution tree containing the above PVs. > > >>Well, the effective branching factor is quite good for Chest. >>Here is the timing for the increasing depths: >> >> seconds >># 1 0.00 0.87 1- 0 >># 2 0.00 1.00 1- 0 >># 3 0.00 0.95 70- 0 >># 4 0.08 1.07 465- 0 >># 5 0.37 1.27 2085- 0 >># 6 1.46 1.57 7901- 0 >># 7 6.32 2.09 34402- 0 >># 8 25.78 2.57 141569- 0 >># 9 87.41 3.28 500658- 0 >># 10 478.70 3.56 2712514- 478 >># 11 1570.93 4.26 8976242- 1058845 >># 12 7659.24 3.73 44489747- 35741846 > # 13 41979.42 3.21 233216096- 224468195 > >>depth 7-> 8: 4.079 >>depth 8-> 9: 3.390 >>depth 9->10: 5.476 >>depth 10->11: 3.281 >>depth 11->12: 4.875 > depth 12->13: 5.480 > >>It changes a bit up and down, but stays between 3 and 5.5 so far, which >>is not bad for such a crowded board and 69 initial legal moves. >> >>But no cigar, yet. >> >>>>proven that lots of the other moves lose already though. >>>>proved that 26 of the other moves lose after 10 minutes search.. >>>> >>>>Angrim >> >>Yes, for (nearly) all partial mate-in-3 Chest tried to mate the attacker >>directly in 1 move, which succeeded in 16.2% of the cases. A more >>sophisticated heuristic might succeed in many more cases. >> >>Now, Leonid, should I go on? Depth 13 and 14 will take around 9 hours >>and 1.5 days! What is your shortest (selective) solution? >> >>Cheers, >>Heiner > >My estimates above were even a bit low. This mate problem was definitely >a heavy one. But I'm sure, you will not run out of such problems, Leonid :-) Thanks, Heiner, for two solutions! Since position is symmetrical I expected that it could be so. Mainly when for simplified version for it, I and one other man came with second mirror solution. Actually, I even thought that, maybe, I must be not afraid to put here my highly artificial mates. Today I tried to soften "bad impression" by putting one "natural" on the Web. I personally like tough one. Esthetically they make me think about cartoons and action movies that I enjoy. From practical point of view, they make all bugs sparkling with revealing, hellish fire. Happy weekend for you as well! Leonid. >Happy weekend! >Heiner
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