Author: Robert Hyatt
Date: 08:29:11 03/24/03
Go up one level in this thread
On March 24, 2003 at 03:19:41, Will Singleton wrote:
>On March 24, 2003 at 02:52:40, Will Singleton wrote:
>
>>On March 24, 2003 at 02:25:33, Bernhard Bauer wrote:
>>
>>>On March 24, 2003 at 02:07:31, Will Singleton wrote:
>>>
>>>>Position from Baron – Amateur bm Qxc2
>>>>[D]2rr3k/pb3ppp/4p3/4P3/1n1B3R/1P4P1/P1q4P/1Q1RKB2 w - - 0 30
>>>>
>>>>For some reason, Ruffian and Crafty have a very tough time with this one. I
>>>>wonder whether this could be due to some similarity between them. A problem in
>>>>repetition detection, perhaps? On my machine, amd 1.6ghz:
>>>>
>>>> Fail-low solution
>>>>Yace 0:15 0:20
>>>>CM 0:15 0:30
>>>>Shredder 0:35 0:45
>>>>Amateur 0:20 0:50
>>>>Ruffian 2:34 3:54
>>>>Crafty 5:42 > 9 minutes
>>>>
>>>>---------------------------------
>>>>[Event "Computer chess game"]
>>>>[Site "MICRON"]
>>>>[Date "2003.03.23"]
>>>>[Round "1"]
>>>>[White "The Baron 0.99.5a"]
>>>>[Black "Amateur 2.44"]
>>>>[Result "0-1"]
>>>>[TimeControl "40/600"]
>>>>
>>>>1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. g3 Be7 5. Bg2 O-O 6. Qc2 c6 7. O-O Nbd7 8.
>>>>Nbd2 b6 9. e4 Bb7 10. e5 Ne8 11. b3 Rc8 12. Bb2 c5 13. Rac1 cxd4 14. Nxd4
>>>>Kh8 15. Rfe1 Nc7 16. cxd5 Nxd5 17. Qb1 Nc5 18. Red1 Qd7 19. Ne4 Rfd8 20.
>>>>Ne2 Qb5 21. Nd4 Qa6 22. Nxc5 Bxc5 23. Bf1 Qa5 24. Rc4 b5 25. Nxb5 Qxb5 26.
>>>>Rh4 Bxf2+ 27. Kxf2 Qc5+ 28. Bd4 Qc2+ 29. Ke1 Nb4 30. Bxa7 Qc3+ 31. Kf2 Qf3+
>>>>32. Kg1 Qh1+ 33. Kf2 Qf3+ 34. Kg1 h5 35. Rd6 g5 36. Rh3 Rxd6 37. exd6 Rc2
>>>>38. Qxc2 Nxc2 39. d7 Qd5 40. Bb6 Qxd7 41. Rxh5+ Kg7 42. Rxg5+ Kf6 43. Rb5
>>>>Qd1 44. a3 Bc6 45. Rb4 Nxb4 46. g4 Nd3 47. Bd4+ Ke7 48. Bc5+ Nxc5 49. h4
>>>>{Baron resigns} 0-1
>>>
>>>Crafty 19.3 needs 28 sec on an AMD 1,8 GHz. So I can't see a very tough time.
>>>Regards
>>>Bernhard
>>
>>Very interesting. I was using Crafty 19.1. I just ran the position on 19.2 and
>>19.3, confirming your results with 19.3. 19.2, however, behaves likes 19.1,
>>taking several minutes. I'm off to check the source changes.
>>
>
>More interesting. 19.3 has rewritten the repetition code. As I pointed out in
>the original post, a problem with repetition detection might cause difficulty
>with this position. What do you know.
>
>Will
The repetition code had a bug, but _only_ in SMP versions. That was why it was
rewritten.
More likely, the changes to the extension code account for seeing this at a much
earlier
iteration... Particularly starting the depth at 1.5 rather than 1.0 so that the
first fractional
extensions cause real extensions.
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