Author: A. Steen
Date: 21:07:38 11/20/05
Go up one level in this thread
On November 20, 2005 at 23:23:14, enrico carrisco wrote:
>On November 20, 2005 at 23:03:44, A. Steen wrote:
>
>>On November 20, 2005 at 22:42:02, enrico carrisco wrote:
::: snipped ten examples of engines analysing a KRK position; all found the
best move (Ke3) immediately in a tiny fraction of a second and gave it a high
evaluation :::
>>>Please -- will the die-hard "EGTB files are a waste" believers please stand-up.
>>>
>>>Regards,
>>>
>>>Enrico.
>>
>>
>>I think EGTBs are useful, but I think your examples illustrate the opposite of
>>what you are trying to prove. :)
>>
>
>Or perhaps you miss my point and need a clearer path of explanation.
We'll see what I missed. :)
>>Good chess engines are not optimised mate-finders, but optimised win-finders,
>>and there is a big difference!
>
>So, after viewing the example below, your definition of win-finder would be
>taking the scenic route? Your statement is nonsense as finding mate is >winning.
My statement is not "nonsense". :)
You are confusing at least four potentially distinct things:
*a) winning by the fastest method available, and knowing it is fastest and a
100% sure win (i.e. a seen mate)
*b) winning by the fastest method available but not knowing it is fastest or a
100% sure win
*c) winning by a more "scenic route" and knowing it is a 100% sure win (a seen
mate)
*d) winning by a more "scenic route" and not knowing it is a 100% sure win.
A tablebase result would be of type (a).
All your chosen engine analysis examples were of type (b), with the move found
(and potentially made, if the TC was demanding enough) as fast as a tablebase
lookup would be. Whether directly (root position) or while carrying out an
evaluation/search.
So in the single position example given by you, the EGTBs have no advantage.
Had you chosen examples of types (c) or (d), you may likely have had a point.
But you did not.
Whether the program knows or not it is a fastest win is usually irrelevant as
long as it makes the perfect move fast enough. As Rhett Butler put it: "Frankly
my dear, I don't give a damn." In a manner of speaking.
> By the way -- your profile is missing.
Excellent, and most highly relevant to the discussion.
>>So whether the programs found mate instantly, let alone the quickest mate, or
>>not is irrelevant.
>>
>>In all your examples, the programs found the fastest winning move (Ke3 - and I
>>don't need to check that, do I - surely everything else must be at least 1 move
>>slower?) in much less than one second. Probably in just a few thousandths of a
>>second. And all gave it a high evaluation. Only one (J9) ever wavered from
>>that choice Ke3.
>>
>>So, even if EGTBs were being used in the search itself, the presence of EGTBs
>>would not have helped at all in this example. Chess Challenger 7 could not
>>handle KRK, but we have moved on since then.
>>
>>Simply put, you need a more complex example. :)
>
>I wasn't trying to hang Fruit with my example, so I didn't hammer my point clear
>enough, perhaps. Yes it found the next suceeding move but not knowing a clear
>path to mate in very simplistic ending can end with a lot of wasted time -- even a flag.
Some endings - many endings - only look simplistic.
>Look at moves 86. on in the following exmaple. Fruit 2.2.1 was black.
OK. But a bit earlier, at 58., there is what I think may be a blunder by white.
>
>1. Nf3 {0:05:03} Nf6 {0:05:03} 2. c4 {0:05:06} c5 {0:05:06} 3. g3 {0:05:08}
>d5 {0:05:09} 4. cxd5 {0:05:11} Nxd5 {0:05:11} 5. Bg2 {0:05:14} Nc6 {0:05:14}
>6. Nc3 {0:05:17} Nc7 {0:05:17} 7. Qa4 {0:05:20} Bd7 {0:05:20} 8. Qe4
>{0:05:23} g6 {0:05:23} 9. Ne5 {0:05:26} Bg7 {0:05:26} 10. Nxd7 {0:05:29}
>Qxd7 {0:05:29} 11. O-O {0:05:32} O-O {0:05:32} 12. a3 {0:05:35} Rac8
>{0:05:34} 13. b4 {0:05:37} cxb4 {0:05:23} 14. axb4 {0:05:25} Nb5 {0:05:25}
>15. Bb2 {0:05:07} a6 {0:05:28} 16. Rfd1 {0:04:41} Nd6 {0:05:31} 17. Qd5
>{0:04:25} Rfd8 {0:05:34} 18. Qa2 {0:04:14} e6 {0:05:28} 19. Rdc1 {0:04:16}
>Nf5 {0:05:19} 20. Bxc6 {0:04:16} Rxc6 {0:05:00} 21. d3 {0:04:00} Nd4
>{0:04:34} 22. Kg2 {0:03:54} e5 {0:04:19} 23. Rab1 {0:03:30} h5 {0:04:22} 24.
>Ne4 {0:03:25} Nxe2 {0:04:21} 25. Rxc6 {0:03:18} Qxc6 {0:04:17} 26. Qc4
>{0:03:14} Qd5 {0:04:16} 27. Qxd5 {0:03:08} Rxd5 {0:04:19} 28. Kf3 {0:03:04}
>Nd4+ {0:04:12} 29. Bxd4 {0:03:06} Rxd4 {0:04:01} 30. Ke3 {0:03:09} b6
>{0:03:46} 31. Nd2 {0:03:01} Bh6+ {0:03:45} 32. Ke2 {0:03:00} Bxd2 {0:03:43}
>33. Kxd2 {0:02:55} Kg7 {0:03:43} 34. Kc3 {0:02:46} Rd6 {0:03:42} 35. Re1
>{0:02:42} Kf6 {0:03:30} 36. Re4 {0:02:45} Kf5 {0:03:22} 37. f4 {0:02:39}
>Rc6+ {0:03:23} 38. Kd2 {0:02:30} exf4 {0:03:18} 39. Rxf4+ {0:02:32} Ke6
>{0:03:14} 40. Re4+ {0:02:32} Kd7 {0:03:07} 41. Re1 {0:02:28} a5 {0:02:59}
>42. Ra1 {0:02:28} axb4 {0:02:52} 43. Rb1 {0:02:31} Rf6 {0:02:46} 44. Ke3
>{0:02:30} Re6+ {0:02:39} 45. Kf4 {0:02:33} Re2 {0:02:32} 46. Rxb4 {0:02:28}
>Rf2+ {0:02:26} 47. Ke4 {0:02:19} Rxh2 {0:02:29} 48. Rxb6 {0:02:13} Rh3
>{0:02:32} 49. Kf4 {0:02:07} h4 {0:02:31} 50. gxh4 {0:02:05} Rxd3 {0:02:26}
>51. Kg5 {0:02:06} Rf3 {0:02:14} 52. Rb7+ {0:02:02} Ke6 {0:02:17} 53. Rb6+
>{0:01:54} Ke7 {0:02:19} 54. Rb7+ {0:01:51} Kf8 {0:02:10} 55. Rb5 {0:01:54}
>Rh3 {0:02:05} 56. Kf6 {0:01:56} Kg8 {0:02:03} 57. Rb8+ {0:01:57} Kh7
>{0:02:05} 58. Kxf7 {0:01:54} Rxh4 {0:02:03} 59. Kf6 {0:01:57} Rh5 {0:02:05}
>60. Rb1 {0:01:52} Rf5+ {0:02:08} 61. Ke6 {0:01:47} Kh6 {0:02:10} 62. Rb2
>{0:01:42} Rf4 {0:02:13} 63. Rh2+ {0:01:38} Kg5 {0:02:15} 64. Ke5 {0:01:28}
>Rh4 {0:02:18} 65. Rf2 {0:01:23} Kh5 {0:02:21} 66. Rf8 {0:01:22} g5 {0:02:23}
>67. Rh8+ {0:01:17} Kg4 {0:02:26} 68. Rb8 {0:01:15} Rh1 {0:02:29} 69. Kf6
>{0:01:13} Rh6+ {0:02:31} 70. Ke5 {0:01:11} Rc6 {0:02:34} 71. Ke4 {0:01:04}
>Re6+ {0:02:36} 72. Kd4 {0:01:03} Re1 {0:02:39} 73. Rh8 {0:00:58} Kg3
>{0:02:41} 74. Kd3 {0:00:55} g4 {0:02:44} 75. Rh6 {0:00:50} Kg2 {0:02:46} 76.
>Rf6 {0:00:44} g3 {0:02:48} 77. Rf7 {0:00:41} Re5 {0:02:51} 78. Rh7 {0:00:41}
>Kf3 {0:02:54} 79. Rf7+ {0:00:41} Kg4 {0:02:56} 80. Rf1 {0:00:42} g2
>{0:02:58} 81. Rb1 {0:00:19} Kf3 {0:03:01} 82. Kd4 {0:00:17} Rg5 {0:03:03}
>83. Rg1 {0:00:04} Kf2 {0:03:06} 84. Rd1 {0:00:05} g1=Q {0:03:08} 85. Rxg1
>{0:00:08} Rxg1 {0:03:02} 86. Kd5 {0:00:07} Re1 {0:02:48} 87. Kd4 {0:00:05}
>Rd1+ {0:02:26} 88. Ke4 {0:00:04} Rd8 {0:02:19} 89. Ke5 {0:00:06} Kf3
>{0:02:00} 90. Ke6 {0:00:09} Ke4 {0:01:44} 91. Kf6 {0:00:07} Kd5 {0:01:22}
>92. Ke7 {0:00:05} Rc8 {0:01:11} 93. Kf6 {0:00:07} Rc3 {0:01:03} 94. Kf5
>{0:00:07} Rh3 {0:00:57} 95. Kf4 {0:00:07} Rh4+ {0:00:56} 96. Kf5 {0:00:09}
>Rh5+ {0:00:52} 97. Kf4 {0:00:07} Re5 {0:00:41} 98. Kf3 {0:00:05} Rf5+
>{0:00:36} 99. Ke3 {0:00:04} Rf7 {0:00:32} 100. Kd2 {0:00:04} Kc5 {0:00:24}
>101. Ke3 {0:00:05} Rf1 {0:00:19} 102. Ke4 {0:00:04} Kd6 {0:00:11} 103. Kd3
>{0:00:04} Rf3+ {0:00:05} 104. Ke4 {0:00:04} Rf8 {0:00:04} 105. Kd4 {0:00:04}
>Rf4+ {0:00:07} 106. Kd3 {0:00:05} Kc5 {0:00:04} 107. Ke3 {0:00:06} Ra4
>{0:00:04} 108. Kd3 {0:00:06} Rd4+ {0:00:07} 109. Ke3 {0:00:06} Rb4 {0:00:04}
>110. Kd3 {0:00:06} Rh4 {0:00:04} 111. Ke3 {0:00:06} Kc4 {0:00:05} 112. Kf3
>{0:00:08} Kd3 {0:00:04} 113. Kg3 {0:00:06} Rb4 {0:00:07} 114. Kf3 {0:00:05}
>Kd2 {0:00:10} 115. Kf2 {0:00:05} Rb3 {0:00:12} 116. Kf1 {0:00:07} Ke3
>{0:00:12} 117. Kg2 {0:00:10} Ke2 {0:00:13} 118. Kg1 {0:00:13} Kf3 {0:00:14}
>119. Kh2 {0:00:15} Rb1 {0:00:14} 120. Kh3 {0:00:18} Rh1# {0:00:16}
>{White checkmated}
>0-1
Well, EGTBs hook on to the win once white allows the pawn exchange at 58.,
giving m/44. So at 86, with optimal play for both, we should be at about m/16.
In fact we are at m/13 as white has played worse. 86 + 13 = 99. So there was
an extension by 120-99 = 21 moves, caused by stupid play by black starting with
92 and then getting worse.
Yes, this is a better example from you. :)
It illustrates that repeated "scenic routes" can literally result in running
around in pointless rectangles (like the BR does).
Your single position example did not.
Aside: EG play by both Fruity and Fritzy9 is sometimes suspect. It comes with
the territory of making the progs smarter, maybe.
I am on the side of EGTBs.
Best,
A.S.
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