Author: Heiner Marxen
Date: 17:04:10 04/13/02
Go up one level in this thread
On April 13, 2002 at 15:59:39, leonid wrote: >On April 13, 2002 at 15:15:07, John Merlino wrote: > >>On April 13, 2002 at 14:49:12, leonid wrote: >> >>>On April 13, 2002 at 14:36:31, John Merlino wrote: >>> >>>>On April 13, 2002 at 07:49:31, leonid wrote: >>>> >>>>>Hi! >>>>> >>>>>Recently I found that for many programs selective search for mate is pretty >>>>>different. At least, in few recent mate positions my default selective was >>>>>useless. I am curious to see how many other programs can solve this position by >>>>>selective. Mine was useless on this even if it look like to be ideal for >>>>>selective. Position in itself is not deep, or very difficult. >>>>> >>>>>[D]1qbqkbq1/QBRNBNQ1/1QnQpQn1/1q1RQ1p1/3rn3/2Q2Q2/Q6K/1r4r1 w - - >>>>> >>>>>Please indicate your result, never mind your way of solving this mate. >>>>> >>>>>Thanks, >>>>>Leonid. >>>> >>>>I don't know if it's the shortest mate, but it took Chessmaster a long time (on >>>>a PIII-733) to find Mate in 10 anyway (with some HUGE evals along the way), as >>>>the first seven moves are all non-checking moves: >>> >>> >>>So, actually Chessmaster took this position by selective and not that far from >>>shortest one. Pretty good! >>> >>>This position is mate in 9 moves. >>> >>>Cheers, >>>Leonid. >> >>I'm trying Chessmaster's Solve for Mate mode. It finished depth 8 in just a few >>minutes, but is taking quite a long time to finish depth 9. It still hasn't >>announced mate in 9, and it has been going for almost 40 minutes on my PIII-733 >>(over five minutes longer than it took to announce Mate in 10 via selective >>search). > > >What is exactly "Mate mode"? Is this forced mate, in other words search that >look for every possible mate and miss no mates? And how you indicated before to >your program to look for mate? > >I remember Chessmater 4000 as very good mate solver but I don't remember exactly >if its mate look like to be forced mate, or selective, or just both in sequence. >Few solutions that were presented here were quick and were found on Chessmater >8000. I am almost sure that they were found by selective search. > >My program also felt big jump in branching factor between 7 and 8 move. It went >to 13.09 after being just before this only 6.3. It could be that later, between >8 and 9 move, branching became even worst. What happened later I don't know. My >program stop just after first solution. Chest shows the same effect (K7/600, 350 MB hash, 3.9 hours): # 4 0.10s [ 5.00] 5kN [ 4.96] 1.02 866- 0 # 5 0.41s [ 4.10] 20kN [ 3.71] 1.15 3165- 0 # 6 1.49s [ 3.63] 75kN [ 3.80] 1.44 10739- 0 # 7 9.59s [ 6.44] 609kN [ 8.16] 1.61 60240- 0 # 8 210.98s [ 22.00] 15973kN [ 26.22] 1.59 1072278- 0 # 9 13847.86s [ 65.64] 1122335kN [ 70.26] 1.69 58979212- 50231311 For depth up to 7 black finds enough checks to hinder white from mating. Going deeper, this does not work any more, and the search trees become large. Chest find 2 solutions for the mate in 9: PV: Qdxe6 Rh1+ Qxh1 Rd2+ Qcxd2 Rxh1+ Kxh1 Nf2+ Qbxf2 Qh8+ Qxh8 Qxd5+ Qaxd5 Qxd7 Nd6+ Qxd6 Qff7# PV: Qxb1 Rh1+ Qbxh1 Rd2+ Qbf2 Rxf2+ Qaxf2 Qh7+ Nh6 Qxh6+ Qxh6 Qxe7 Qhxg6+ Kd8 Nxb8+ Bd7 Rc8# Most of the time black directs what happens. I let Chest print the solution tree 7 plies deep (option -lll) and got over 13,000 lines of output. Wow! Cheers, Heiner >Leonid. > >>jm
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