Author: leonid
Date: 14:42:01 05/04/01
Go up one level in this thread
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). Great, Heiner! It is for sure mate in 13. I just said this to Paul before finding your message. Expected that maybe you will go farther that me, since your branching factor is usually good and you have hash installed. With my hash free (have no idea how much hash will be able to help me) at 10 moves my computer (Celeron 600) took already 2 hours and 7 minutes to say no. My pleasure to see you at work, Heiner! Salut, Leonid. >>> 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. > >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 > >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 > >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
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