Author: Jeremiah Penery
Date: 23:54:32 12/13/03
Go up one level in this thread
On December 13, 2003 at 13:07:00, Robert Hyatt wrote: >On December 12, 2003 at 19:32:45, Slater Wold wrote: > >>On December 12, 2003 at 15:13:40, Will Singleton wrote: >> >>>On December 12, 2003 at 13:49:35, Robert Hyatt wrote: >>> >>>>On December 12, 2003 at 13:40:07, Will Singleton wrote: >>>> >>>>>Here's a position from a recent game, this one gives Amateur fits. >>>>>How long to see black is busted? >>>>> >>>>>[d]4rr2/1b3p1k/pp5p/2b1pQ2/q7/P2R2B1/1PP3PP/2KR4 b - - >>>> >>>> >>>>For Crafty, the bottom begins to fall out at 6 seconds or so, where >>>>it begins to see it is not ahead. By 60 seconds it has failed low >>>>to white a pawn up and climbing: >>>> >>>> 12-> 4.84 -0.69 1. ... Kg8 2. Bxe5 Bf2 3. Rd4 Rxe5 >>>> 4. Qxe5 Re8 5. Rd8 Bc6 6. Rxe8+ Bxe8 >>>> 7. Rd6 Qb5 8. Qf4 Qg5 <HT> >>>> 13 6.66 -- 1. ... Kg8 >>>> 13 15.28 0.31 1. ... Kg8 2. Bxe5 Bf2 3. Bf6 Re2 4. >>>> Rd8 Bc5 5. R8d4 Rxc2+ 6. Qxc2 Qxc2+ >>>> 7. Kxc2 Bxd4 8. Bxd4 Be4+ 9. Kb3 Rd8 >>>> 13-> 17.91 0.31 1. ... Kg8 2. Bxe5 Bf2 3. Bf6 Re2 4. >>>> Rd8 Bc5 5. R8d4 Rxc2+ 6. Qxc2 Qxc2+ >>>> 7. Kxc2 Bxd4 8. Bxd4 Be4+ 9. Kb3 Rd8 >>>> 14 35.70 0.00 1. ... Kg8 2. Bxe5 Bf2 3. Bf6 Re2 4. >>>> Rd8 Bh4 5. Rxf8+ Kxf8 6. Rd8+ Re8 7. >>>> Rxe8+ Qxe8 8. Bxh4 Qe3+ 9. Kb1 Qg1+ >>>> 10. Ka2 Qxg2 11. Qf4 Qxc2 12. Qxh6+ >>>> 14-> 40.01 0.00 1. ... Kg8 2. Bxe5 Bf2 3. Bf6 Re2 4. >>>> Rd8 Bh4 5. Rxf8+ Kxf8 6. Rd8+ Re8 7. >>>> Rxe8+ Qxe8 8. Bxh4 Qe3+ 9. Kb1 Qg1+ >>>> 10. Ka2 Qxg2 11. Qf4 Qxc2 12. Qxh6+ >>>> 15 51.44 -- 1. ... Kg8 >>>> 15 1:30 0.98 1. ... Kg8 2. Bxe5 Bf2 3. Rd4 Rxe5 >>>> 4. Qxe5 Re8 5. Rg4+ Qxg4 6. Qxe8+ Kg7 >>>> 7. Qe5+ f6 8. Qc7+ Kg6 9. Rd7 Qg5+ >>>> 10. Kb1 Bxg2 11. Rg7+ Kf5 12. Rxg5+ >>>> hxg5 >>> >>>That's only half the story. Let it think another half hour. >>> >>>Will >> >>White(1): setboard 4rr2/1b3p1k/pp5p/2b1pQ2/q7/P2R2B1/1PP3PP/2KR4 b - - >>Black(1): st 9999999 >>search time set to 9999999.00. >>Black(1): go >> clearing hash tables >> time surplus 0.00 time limit 166666:39 (166666:39) >> depth time score variation (1) >>starting thread 1 >> 7 0.14 -1.34 1. ... Kg8 2. Bxe5 Bf2 3. Kb1 Rxe5 >> 4. Qxe5 Bxg2 >> 7-> 0.14 -1.34 1. ... Kg8 2. Bxe5 Bf2 3. Kb1 Rxe5 >> 4. Qxe5 Bxg2 >> 8 0.23 -- 1. ... Kg8 >> 8 0.34 -0.89 1. ... Kg8 2. Bxe5 Bf2 3. Rh3 Qe4 4. >> Qxf2 Rxe5 5. Rxh6 Qxg2 6. Qxb6 >> 8-> 0.36 -0.89 1. ... Kg8 2. Bxe5 Bf2 3. Rh3 Qe4 4. >> Qxf2 Rxe5 5. Rxh6 Qxg2 6. Qxb6 >> 9 0.95 -1.12 1. ... Kg8 2. Bxe5 Bf2 3. Qf6 Rxe5 >> 4. Qxe5 Re8 5. Rd8 Rxd8 6. Rxd8+ >> 9-> 0.98 -1.12 1. ... Kg8 2. Bxe5 Bf2 3. Qf6 Rxe5 >> 4. Qxe5 Re8 5. Rd8 Rxd8 6. Rxd8+ >> 10 1.83 -0.97 1. ... Kg8 2. Bxe5 Bf2 3. Qf6 Rxe5 >> 4. Qxe5 Re8 5. Qc7 Bxg2 6. Rd7 >> 10-> 1.90 -0.97 1. ... Kg8 2. Bxe5 Bf2 3. Qf6 Rxe5 >> 4. Qxe5 Re8 5. Qc7 Bxg2 6. Rd7 >> 11 7.12 -0.84 1. ... Kg8 2. Bxe5 Bf2 3. Qf6 Rxe5 >> 4. Qxe5 Qg4 5. g3 Qg5+ 6. Qxg5+ hxg5 >> 7. Rf1 Bc5 8. Rd7 >> 11-> 7.72 -0.84 1. ... Kg8 2. Bxe5 Bf2 3. Qf6 Rxe5 >> 4. Qxe5 Qg4 5. g3 Qg5+ 6. Qxg5+ hxg5 >> 7. Rf1 Bc5 8. Rd7 >> 12 13.15 -- 1. ... Kg8 >> 12 18.67 -0.43 1. ... Kg8 2. Bxe5 Bf2 3. Rd4 Rxe5 >> 4. Qxe5 Re8 5. Rd8 Bc6 6. Rxe8+ Bxe8 >> 7. Rd8 Kf8 8. Kd2 >> 12-> 20.06 -0.43 1. ... Kg8 2. Bxe5 Bf2 3. Rd4 Rxe5 >> 4. Qxe5 Re8 5. Rd8 Bc6 6. Rxe8+ Bxe8 >> 7. Rd8 Kf8 8. Kd2 >> 13 28.70 -- 1. ... Kg8 >> 13 1:02 0.31 1. ... Kg8 2. Bxe5 Bf2 3. Bf6 Re2 4. >> Rd8 Bc5 5. R8d4 Rxc2+ 6. Qxc2 Qxc2+ >> 7. Kxc2 Bxd4 8. Bxd4 Be4+ 9. Kb3 Rd8 >> 13-> 1:08 0.31 1. ... Kg8 2. Bxe5 Bf2 3. Bf6 Re2 4. >> Rd8 Bc5 5. R8d4 Rxc2+ 6. Qxc2 Qxc2+ >> 7. Kxc2 Bxd4 8. Bxd4 Be4+ 9. Kb3 Rd8 >> 14 2:21 0.00 1. ... Kg8 2. Bxe5 Bf2 3. Bf6 Re2 4. >> Rd8 Bh4 5. Rxf8+ Kxf8 6. Rd8+ Re8 7. >> Rxe8+ Qxe8 8. Bxh4 Qe3+ 9. Kb1 Qg1+ >> 10. Ka2 Qxg2 11. Qf4 Qxc2 12. Qxh6+ >> 14-> 2:34 0.00 1. ... Kg8 2. Bxe5 Bf2 3. Bf6 Re2 4. >> Rd8 Bh4 5. Rxf8+ Kxf8 6. Rd8+ Re8 7. >> Rxe8+ Qxe8 8. Bxh4 Qe3+ 9. Kb1 Qg1+ >> 10. Ka2 Qxg2 11. Qf4 Qxc2 12. Qxh6+ >> 15 3:35 -- 1. ... Kg8 >> 15 6:51 0.98 1. ... Kg8 2. Bxe5 Bf2 3. Rd4 Rxe5 >> 4. Qxe5 Re8 5. Rg4+ Qxg4 6. Qxe8+ Kg7 >> 7. Qe5+ f6 8. Qc7+ Kg6 9. Rd7 Qg5+ >> 10. Kb1 Bxg2 11. Rg7+ Kf5 12. Rxg5+ >> hxg5 >> 15-> 31:42 0.98 1. ... Kg8 2. Bxe5 Bf2 3. Rd4 Rxe5 >> 4. Qxe5 Re8 5. Rg4+ Qxg4 6. Qxe8+ Kg7 >> 7. Qe5+ f6 8. Qc7+ Kg6 9. Rd7 Qg5+ >> 10. Kb1 Bxg2 11. Rg7+ Kf5 12. Rxg5+ >> hxg5 (s=2) >> 16 32:56 -- 1. ... Kg8 >>? 16 193:15 1/3* 1. ... Kg8 >>Black(0): ? >> time=193:18 cpu=197% mat=-3 n=20834682079 fh=99% nps=1796k >> ext-> chk=-1921721336 cap=10974209 pp=1617516 1rep=423412478 mate= >>1390210 >> predicted=0 nodes=20834682079 evals=670369456 >> endgame tablebase-> probes=0 hits=0 >> SMP-> split=3793 stop=417 data=12/4096 cpu=382:29 elap=193:18 > > >I have seen worse. What happens is that the aspiration window initially cuts >off all mate scores. But once it fails low, it can't just find any old mate >and cut off analyzing that line. Now it has to follow _all_ mates and that >kills performance. This also happens in endgames where you can potentially >promote a pawn, but it always gets lost, so you can search to great depth. >And eventually you find that you can promote it there, but now all those lines >you got cutoffs on before (where the pawn promoted, but it wasn't forced) now >explode and while the depth 25 search took 10 seconds, the depth 26 search might >not take 10 days... > >It's a known problem with no known solution. > >Even not using aspiration search won't solve it. You can not lower the window to -INF, but rather on the initial fail low move it down -1, then next do -3, and so on. Or just do it for fail-high and that should affect fail-low also (since a fail-low on one side is a fail-high for the other).
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