Author: leonid
Date: 08:12:58 02/10/01
Go up one level in this thread
On February 10, 2001 at 00:51:17, Uri Blass wrote: >On February 09, 2001 at 11:36:04, Heiner Marxen wrote: > >>On February 09, 2001 at 06:51:15, leonid wrote: >> >>>On February 09, 2001 at 06:47:28, leonid wrote: >>> >>>>Hi! >>>> >>>>If you like to solve a forced mate, you can try this position: >>>> >>>>[D]1bqQBnRn/3N2Qb/Q1QN2np/1Q1Q1qpk/4Qqbn/2B1Qrnn/2Q5/K1R5 w - - >>>> >>>>Please, indicate your result. >> >>Chest find a mate in 7 with 1.Qxg5+: >>Qxg5+ Nxg5 Qdxf5 Nhxf5 Qh2+ Bh3 Nf6+ Kh4 Qxh6+ Nxh6 Q4xf4+ Ng4 Qfxg5# >> >>(3.3 hours, K7/600 350MB hash) >> >>>>By curiosity I looked what is the NPS (nodes/second) for this position. Since >>>>the number of moves, during the solution of mate went quit often up to 130 for >>>>whites, NPS was more that impressive. If it could be the same all the time! On >>>>It went up in around 60% as average. It is the same for your program? NPS depend >>>>greatly on number of average moves existing in each ply? >>>> >>>>Thanks, >>>>Leonid. >> >>For Chest on your crowded boards NPS greatly decreases, by a factor around >>2 or 3. Some of the heuristics to gain speed, do not pay off, anymore. >>Hmmm, may be I should improve my heuristics ;-) >>The reduced NPS does not worry me, as long as the job is done quickly. >> >>Heiner > >I believe that removing part of the white pieces may help chest to find the >solution more quickly > >I did not investigate exactly all the pieces that you can remove but without the >white queen at a6 there is also a mate in 7. I tried your new position but could solve it only by selective in 11 moves. Brute force (if branching factor is still the same) it could take some few hours. I don't have any speedy computer beside my main one. Even selective was not so speedy here. It took 24 sec. Leonid. >Here is a position that chess programs accept(I put a rook at g5 instead of a >pawn and removed the white queen at a6) > >[D]1bqQBnRn/3N2Qb/2QN2np/1Q1Q1qrk/4Qqbn/2B1Qrnn/2Q5/K1R5 w - - 0 1 > > >Uri
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