Author: James T. Walker
Date: 17:27:45 11/12/99
Go up one level in this thread
On November 12, 1999 at 11:54:32, Christophe Theron wrote: >On November 12, 1999 at 04:01:39, Bertil Eklund wrote: > >>On November 12, 1999 at 02:00:32, Ed Schröder wrote: >> >>>On November 11, 1999 at 20:18:18, Howard Exner wrote: >>> >>>>Here's the game which ended in a draw.[Event "SSDF 40-2"] >>>>[Site "DK-Albertslund"] >>>>[Date "1999.11.10"] >>>>[Round "23"] >>>>[White "Chess Tiger 12.0 dos K6-2 450,64"] >>>>[Black "Shredder 2 P200MMX 24+8"] >>>>[Result "1/2-1/2"] >>>>[WhiteElo "2645"] >>>>[BlackElo "2503"] >>>>[Annotator "Test: HC Lykke"] >>>> >>>>1. e4 c5 2. Nc3 d6 3. f4 Nc6 4. Nf3 Nf6 5. Bb5 e6 6. Bxc6+ >>>>bxc6 7. d3 Be7 8. e5 Nd5 9. Ne4 dxe5 10. Nxe5 Bb7 11. O-O >>>>O-O 12. Qe2 f6 13. Nc4 Ba6 14. Bd2 Nb6 15. Na5 Qd7 16. Be3 >>>>Na4 17. Qf2 c4 18. b3 f5 19. Nd2 cxd3 20. bxa4 Bb4 21. Nab3 >>>>dxc2 22. Rfe1 Rad8 23. a3 Bc3 24. Nc5 Qe7 25. Nxa6 Bxa1 26. >>>>Rxa1 Qxa3 27. Qe1 Qc3 28. Rc1 Rd3 29. Kf2 Qb2 30. Nc4 Qa2 >>>>31. Ne5 Rd1 32. Qc3 Rxc1 33. Bxc1 Qxa4 34. Nc5 Qa2 35. Ncd7 >>>>Re8 36. Qxc6 Rd8 37. Qc7 Ra8 38. Qb7 Rf8 39. Nxf8 Qa5 40. >>>>Qf7+ Kh8 41. Nxe6 Qb6+ 42. Kg3 Qb3+ 43. Kf2 Qb6+ 44. Ke2 >>>>Qa6+ 45. Kf2 Qb6+ 1/2-1/2 >>>> >>>>Would the game end the same from move 41 on if it were manually played? >>> >>>Rebel-Tiger (beta) plays of course 43.Kh4 announcing mate in 3. >>> >>>No 45.Kf2??? also but 45.Ke3 announcing mate in 5. >>> >>>Perhaps something is wrong with the PGN moves? >>> >>>Even in the end-position Rebel-Tiger (beta) still announces a >>>mate. >>> >>>Ed >>Hi! >> >>In one of my testgames Tiger used 30(!!) moves for a simple mate in 4 or 5 >>moves. Tiger won the game but after 10-15 moves with the same announcement mate >>in 4 or 5 I began to wonder if it should be a draw according to the 50-moves >>rule. >> >>Bertil SSDF > > >I have to say my 'mea culpa' here. > >The problem was not the engine in this case but the time manager. > >I have noticed during the French Championship last year that Tiger could spend a >long time before playing an obvious mate. In fact a mate move was considered as >any other move, so Tiger took his time to play it. This means probably one or >two minutes in a long time controls game. > >I thought that this was very bad manners for the opponent, so I decided to make >it more "elegant" and change the time management. > >The new version stopped to search as soon as a mate in X move was found. So in >this case it moved instantly. > >Great. But it is a bloody mistake. What happens? First, Tiger finds a mate in, >say, 5 moves. So it stops and announces "mate in 5". Then, on the next move, the >first mate it finds is a mate in 6. So it stupidly stopped and announced a mate >in 6, and was happy with it. > >This could be an infinite cycle, Tiger announcing mates in several moves, but >never actually checkmating the opponent. > >I have discovered this (old) bug on Nov 2, 1999, and it is now FIXED. The >current beta version does NOT have the bug, and that's why Ed cannot reproduce >it. > >Thanks to Howard Exner for pointing this out. > > > > Christophe I'm sure happy to 'hear' that's fixed. I'm waiting impatiently :-) for Chess Tiger to hit the streets. By the way, I got a glimpse of it on FICS and it is impressive. It seems like people/computers were standing in line to play it. Jim Walker
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