Author: Dieter Buerssner
Date: 11:49:21 06/11/02
Go up one level in this thread
On June 11, 2002 at 11:52:47, Robert Hyatt wrote:
>On June 10, 2002 at 18:45:03, Dieter Buerssner wrote:
>
>>I'd like to add, that not for all engines, it is some sort of luck, when they
>>remember past analysis, and when not. I am convinced, that for my engine, it is
>>better in general, to analyze from back to front. I am also convinced, that it
>>will not forget previous analysis.
>
>It _must_ unless you have a hash table of infinite size...
In theory, yes. In practice, no. There are many more entries to remember crucial
info, than the number anybody could try out in practice. Uri showed several
time, that he could use the backwards analysis of Yace efficiently.
I could prove a mate in (at least) 182 by this feature by analyzing the
following PGN from back to front (including the variations in the PGN). A task,
that would be totally impossible by analyzing from front to back by a normal
playing program. Anybody should be able to reproduce this. It took me about 45
minutes (I didn't have the variants, and had to input many moves with the mouse.
With the PGN and all its variants, I should be able to reproduce this much
faster). At the end of the analysis I got (with German piece letters):
[D] n1K5/b1p3pp/1pP3p1/1P6/6p1/1p4Pn/1P2N1br/3NRn1k w - -
Position stored with depth 6
8.01 0:00 +M182 1.Kd8 g5 2.Ke7 Lb8 3.Kf8 g6 4.Kg7 La7 5.Kf6 Lb8 6.Ke5 La7
7.Kd4 Lb8 8.Kc3 La7 9.Kb4 Lb8 10.Ka4 La7 11.Ka3 Lb8 12.Kb4 La7 13.Kc3 Lb8 14.Kd4
(67.216) 114.5
8.12 0:02 +M182 1.Kd8 g5 2.Ke7 Lb8 3.Kf8 g6 4.Kg7 La7 5.Kf6 Lb8 6.Ke5 La7
7.Kd4 Lb8 8.Kc3 La7 9.Kb4 Lb8 10.Ka4 La7 11.Ka3 Lb8 12.Kb4 La7 13.Kc3 Lb8 14.Kd4
(349.585) 145.0
The GUI I used cannot show the whole line, while it was in principle available,
The search tree I analyzed from back to front:
[Event "Fabel-haft"]
[Site "?"]
[Date "2002.04.26"]
[Round "?"]
[White "Yace"]
[Black "Yace"]
[Result "*"]
[SetUp "1"]
[FEN "n1K5/b1p3pp/1pP3p1/1P6/6p1/1p4Pn/1P2N1br/3NRn1k w - -"]
1. Kd8 {23s} Bb8 {17s} (1... h6 {37s} 2. Kc8 {4s} h5 {9s}
(2... g5 {Matt in 158}) 3. Kd8 {4s} Bb8 {3s} (3... g5
{13s}) (3... h4 {19s} 4. Ke7 {5s} g5 {Matt in 134}) 4. Ke7
{2s} g5 {7s} (4... Ba7 {14s} 5. Kf8 {2s} Bb8 {4s} 6. Kxg7
{1s} Ba7 {4s} 7. Kf6 {Matt in 126}) 5. Kf8 {10s} g6 {Matt
in 149}) 2. Ke7 {24s} g5 {14s} (2... Ba7 {1:02m} 3. Kf8
{7s} h6 {4s} (3... Bb8 {26s} 4. Kxg7 {5s} Ba7 {5s} 5. Kf6
{15s} Bb8 {0s} 6. Ke5 {1s} Ba7 {1s} 7. Kd4 {1s} Bb8 {0s}
8. Kc3 {2s} Ba7 {0s} 9. Kb4 {3s} Bb8 {0s} 10. Ka3 {1s} Ba7
{0s} 11. Ka4 {2s} Bb8 {0s} 12. Kb4 {1s} Ba7 {0s} 13. Kc3
{3s} Bb8 {1s} 14. Kd4 {2s} Ba7 {1s} 15. Ke5 {1s} Bb8 {1s}
16. Kf6 {9s} Ba7 {1s} 17. Ke7 {1s} Bb8 {1s} 18. Kd8 {1s}
Ba7 {4s} 19. Kc8 {2s} g5 {Matt in 149}) 4. Kxg7 {3s} h5
{5s} (4... Bb8 {23s} 5. Kf6 {39s} Ba7 {5s} 6. Ke7 {2s} Bb8
{1s} 7. Kd8 {2s} Ba7 {0s} 8. Kc8 {4s} Bb8 {19s} (8... g5
{Matt in 128}) 9. Kxb8 {2s} h5 {6s} 10. Kc8 {Matt in 15})
5. Kf6 {28s} Bb8 {6s} 6. Ke5 {2s} Ba7 {0s} 7. Kd4 {2s} Bb8
{0s} 8. Kc3 {2s} Ba7 {0s} 9. Kb4 {2s} Bb8 {0s} 10. Ka3 {2s}
Ba7 {0s} 11. Ka4 {2s} Bb8 {0s} 12. Kb4 {1s} Ba7 {1s}
13. Kc3 {1s} Bb8 {0s} 14. Kd4 {2s} Ba7 {0s} 15. Ke5 {1s}
Bb8 {1s} 16. Kf6 {2s} Ba7 {0s} 17. Ke7 {1s} Bb8 {0s}
18. Kd8 {1s} Ba7 {0s} 19. Kc8 {2s} h4 {3s} 20. Kd8 {9s} Bb8
{1s} 21. Ke7 {8s} Ba7 {2s} 22. Kf6 {2s} Bb8 {0s} 23. Ke5
{1s} Ba7 {0s} 24. Kd4 {1s} Bb8 {1s} 25. Kc3 {4s} Ba7 {0s}
26. Kb4 {3s} Bb8 {0s} 27. Ka3 {1s} Ba7 {0s} 28. Ka4 {2s}
Bb8 {0s} 29. Kb4 {1s} Ba7 {0s} 30. Kc3 {1s} Bb8 {0s}
31. Kd4 {1s} Ba7 {0s} 32. Ke5 {1s} Bb8 {0s} 33. Kf6 {1s}
Ba7 {0s} 34. Ke7 {2s} Bb8 {0s} 35. Kd8 {1s} Ba7 {0s}
36. Kc8 {1s} hxg3 {Matt in 94}) 3. Kf8 {23s} g6 {4s}
(3... h6 {18s} 4. Kxg7 {4s} h5 {3s} (4... Ba7 {15s} 5. Kf6
{1:01m} Bb8 {0s} 6. Ke5 {3s} Ba7 {1s} 7. Kd4 {1s} Bb8 {0s}
8. Kc3 {3s} Ba7 {0s} 9. Kb4 {7s} Bb8 {0s} 10. Ka3 {1s} Ba7
{11s} 11. Ka4 {1s} Bb8 {0s} 12. Kb4 {2s} Ba7 {0s} 13. Kc3
{1s} Bb8 {0s} 14. Kd4 {2s} Ba7 {0s} 15. Ke5 {1s} Bb8 {0s}
16. Kf6 {3s} Ba7 {1s} 17. Ke7 {1s} Bb8 {0s} 18. Kd8 {1s}
Ba7 {0s} 19. Kc8 {3s} h5 {5s} 20. Kd8 {6s} Bb8 {1s} 21. Ke7
{1s} Ba7 {0s} 22. Kf6 {2s} Bb8 {0s} 23. Ke5 {1s} Ba7 {1s}
24. Kd4 {1s} Bb8 {0s} 25. Kc3 {2s} Ba7 {0s} 26. Kb4 {1s}
Bb8 {1s} 27. Ka3 {1s} Ba7 {0s} 28. Ka4 {1s} Bb8 {0s}
29. Kb4 {1s} Ba7 {0s} 30. Kc3 {1s} Bb8 {1s} 31. Kd4 {1s}
Ba7 {2s} 32. Ke5 {2s} Bb8 {0s} 33. Kf6 {1s} Ba7 {0s}
34. Ke7 {1s} Bb8 {0s} 35. Kd8 {1s} Ba7 {0s} 36. Kc8 {Matt
in 95}) 5. Kf8 {28s} (5. Kh7 {14s}) 5... Ba7 {8s} 6. Ke7
{13s} h4 {6s} (6... Bb8 {16s} 7. Kd8 {7s} Ba7 {1s} 8. Kc8
{6s} h4 {13s} 9. Kd8 {Matt in 94}) 7. Kf6 {14s} Bb8 {3s}
8. Ke5 {2s} Ba7 {1s} 9. Kd4 {3s} Bb8 {0s} 10. Kc3 {1s} Ba7
{0s} 11. Kb4 {2s} Bb8 {0s} 12. Ka3 {2s} Ba7 {0s} 13. Ka4
{1s} Bb8 {0s} 14. Kb4 {1s} Ba7 {0s} 15. Kc3 {3s} Bb8 {0s}
16. Kd4 {1s} Ba7 {0s} 17. Ke5 {1s} Bb8 {1s} 18. Kf6 {1s}
Ba7 {4s} 19. Ke7 {1s} Bb8 {0s} 20. Kd8 {2s} Ba7 {0s}
21. Kc8 {2s} Bb8 {5s} (21... hxg3 {27s} 22. Nxg3+ {etc.,
Matt in 77}) 22. Kxb8 {2s} hxg3 {3s} 23. Nxg3+ {3s} Kg1
{0s}) (3... Ba7 {28s} 4. Kxg7 {3s} Bb8 {2s} 5. Kf6 {25s}
Ba7 {0s} 6. Ke7 {1s} Bb8 {0s} 7. Kd8 {1s} Ba7 {0s} 8. Kc8
{4s} h6 {6s} (8... Bb8 {16s} 9. Kxb8 {2s}) 9. Kd8 {7s} Bb8
{2s} 10. Ke7 {Matt in 127}) 4. Kg7 {19s} Ba7 {8s} 5. Kf6
{48s} Bb8 {6s} 6. Ke5 {25s} Ba7 {4s} 7. Kd4 {7s} Bb8 {1s}
8. Kc3 {4s} Ba7 {23s} 9. Kb4 {3s} Bb8 {6s} 10. Ka4 {3s} Ba7
{27s} 11. Ka3 {1s} Bb8 {6s} 12. Kb4 {3s} Ba7 {19s} 13. Kc3
{1s} Bb8 {6s} 14. Kd4 {3s} Ba7 {3s} 15. Ke5 {4s} Bb8 {29s}
16. Kf6 {1s} Ba7 {3s} 17. Ke7 {5s} Bb8 {0s} 18. Kd8 {4s}
Ba7 {4s} 19. Kc8 {20s} h6 {6s} 20. Kd8 {35s} Bb8 {0s}
21. Ke7 {3s} Ba7 {3s} 22. Kf8 {3s} Bb8 {0s} 23. Kg7 {6s}
Ba7 {32s} 24. Kh7 {3s} Bb8 {2s} 25. Kh8 {1s} Ba7 {45s}
26. Kg7 {3s} Bb8 {2s} 27. Kf8 {3s} Ba7 {1s} 28. Ke7 {13s}
Bb8 {0s} 29. Kd8 {3s} Ba7 {0s} 30. Kc8 {5s} h5 {28s}
(30... Bb8 {12s} 31. Kxb8 {2s} h5 {6s} 32. Kc8 {2s} h4 {2s}
33. Kd8 {7s} hxg3 {4s} 34. Nxg3+ {3s}) 31. Kd8 {41s} Bb8
{2s} 32. Ke7 {2s} Ba7 {0s} 33. Kf8 {2s} Bb8 {0s} 34. Kg7
{1s} Ba7 {0s} 35. Kh8 {6s} Bb8 {0s} 36. Kh7 {2s} Ba7 {1s}
37. Kg7 {2s} Bb8 {0s} 38. Kf8 {1s} Ba7 {0s} 39. Ke7 {1s}
Bb8 {1s} 40. Kd8 {1s} Ba7 {0s} 41. Kc8 {2s} h4 {21s}
(41... Bb8 {30s} 42. Kxb8 {5s} h4 {9s}) 42. Kd8 {31s} Bb8
{0s} 43. Ke7 {3s} Ba7 {1s} 44. Kf8 {9s} Bb8 {0s} 45. Kg7
{1s} Ba7 {0s} 46. Kh8 {1s} Bb8 {0s} 47. Kh7 {1s} Ba7 {2s}
48. Kg7 {3s} Bb8 {0s} 49. Kf8 {1s} Ba7 {0s} 50. Ke7 {1s}
Bb8 {0s} 51. Kd8 {1s} Ba7 {0s} 52. Kc8 {2s} hxg3 {31s}
53. Nxg3+ {17s} Kg1 {3s} 54. Ne2+ {36s} Kh1 {1s} 55. Kd8
{40s} Bb8 {0s} 56. Ke7 {8s} Ba7 {1s} 57. Kf6 {1s} Bb8 {3s}
58. Ke5 {2s} Ba7 {0s} 59. Kd4 {2s} Bb8 {0s} 60. Kc3 {1s}
Ba7 {1s} 61. Kb4 {2s} Bb8 {1s} 62. Ka3 {6s} Ba7 {3s}
63. Ka4 {6s} Bb8 {0s} 64. Kb4 {1s} Ba7 {0s} 65. Kc3 {3s}
Bb8 {0s} 66. Kd4 {1s} Ba7 {1s} 67. Ke5 {1s} Bb8 {0s}
68. Kf6 {4s} Ba7 {4s} 69. Ke7 {1s} Bb8 {0s} 70. Kd8 {1s}
Ba7 {1s} 71. Kc8 {3s} g3 {34s} 72. Nxg3+ {1s} Kg1 {1s}
73. Ne2+ {2s} Kh1 {2s} 74. Kd8 {34s} Bb8 {1s} 75. Ke7 {2s}
Ba7 {0s} 76. Kf6 {2s} Bb8 {0s} 77. Ke5 {1s} Ba7 {0s}
78. Kd4 {2s} Bb8 {1s} 79. Kc3 {1s} Ba7 {0s} 80. Kb4 {3s}
Bb8 {2s} 81. Ka3 {3s} Ba7 {1s} 82. Ka4 {1s} Bb8 {0s}
83. Kb4 {1s} Ba7 {0s} 84. Kc3 {2s} Bb8 {0s} 85. Kd4 {2s}
Ba7 {2s} 86. Ke5 {2s} Bb8 {0s} 87. Kf6 {1s} Ba7 {0s}
88. Ke7 {1s} Bb8 {0s} 89. Kd8 {1s} Ba7 {0s} 90. Kc8 {3s} g4
{3s} 91. Kd8 {40s} Bb8 {0s} 92. Ke7 {1s} Ba7 {0s} 93. Kf6
{2s} Bb8 {1s} 94. Ke5 {1s} Ba7 {1s} 95. Kd4 {3s} Bb8 {2s}
96. Kc3 {1s} Ba7 {1s} 97. Kb4 {1s} Bb8 {0s} 98. Ka3 {1s}
Ba7 {1s} 99. Ka4 {1s} Bb8 {0s} 100. Kb4 {1s} Ba7 {0s}
101. Kc3 {1s} Bb8 {1s} 102. Kd4 {1s} Ba7 {0s} 103. Ke5 {1s}
Bb8 {1s} 104. Kf6 {1s} Ba7 {2s} 105. Ke7 {1s} Bb8 {0s}
106. Kd8 {1s} Ba7 {0s} (106... g3 {1:48m}) 107. Kc8 {2s} g5
{36s} (107... g3 {216:34m} 108. Nxg3+ {1:26m} Kg1 {3s}
109. Ne2+ {1s} Kh1 {4s} 110. Kd8 {9s} Bb8 {2s} 111. Ke7
{1s} Ba7 {0s} 112. Kf6 {2s} Bb8 {0s} 113. Ke5 {1s} Ba7 {0s}
114. Kd4 {1s} Bb8 {1s} 115. Kc3 {3s} Ba7 {0s} 116. Kb4 {1s}
Bb8 {1s} 117. Ka3 {1s} Ba7 {0s} 118. Ka4 {1s} Bb8 {0s}
119. Kb4 {2s} Ba7 {1s} 120. Kc3 {4s} Bb8 {4s} 121. Kd4 {1s}
Ba7 {0s} 122. Ke5 {1s} Bb8 {0s} 123. Kf6 {1s} Ba7 {0s}
124. Ke7 {1s} Bb8 {0s} 125. Kd8 {1s} Ba7 {0s} 126. Kc8 {1s}
g5 {4s}) (107... Bb8 {16s} 108. Kxb8 {6s} g5 {3s} 109. Kc8
{21s} g3 {4s} 110. Nxg3+ {2s} Kg1 {4s} 111. Ne2+ {1s} Kh1
{2s} 112. Kd8 {10s} g4 {3s}) 108. Kd8 {4s} Bb8 {0s}
109. Ke7 {1s} Ba7 {0s} 110. Kf6 {2s} Bb8 {0s} 111. Ke5 {1s}
Ba7 {0s} 112. Kd4 {2s} Bb8 {0s} 113. Kc3 {1s} Ba7 {0s}
114. Kb4 {2s} Bb8 {0s} 115. Ka3 {1s} Ba7 {0s} 116. Ka4 {1s}
Bb8 {0s} 117. Kb4 {1s} Ba7 {0s} 118. Kc3 {2s} Bb8 {1s}
119. Kd4 {3s} Ba7 {1s} 120. Ke5 {1s} Bb8 {1s} 121. Kf6 {1s}
Ba7 {1s} 122. Ke7 {1s} Bb8 {0s} 123. Kd8 {1s} Ba7 {1s}
124. Kc8 {2s} g3 {3s} (124... Bb8 {46s} 125. Kxb8 {4s} g3
{12s}) 125. Nxg3+ {17s} Kg1 {8s} 126. Ne2+ {3s} Kh1 {0s}
127. Kd8 {22s} Bb8 {3s} 128. Ke7 {1s} Ba7 {0s} 129. Kf6
{2s} Bb8 {0s} 130. Ke5 {1s} Ba7 {0s} 131. Kd4 {1s} Bb8 {1s}
132. Kc3 {4s} Ba7 {8s} 133. Kb4 {1s} Bb8 {0s} 134. Ka3 {1s}
Ba7 {1s} 135. Ka4 {1s} Bb8 {0s} 136. Kb4 {1s} Ba7 {0s}
137. Kc3 {1s} Bb8 {0s} 138. Kd4 {1s} Ba7 {0s} 139. Ke5 {1s}
Bb8 {0s} 140. Kf6 {2s} Ba7 {0s} 141. Ke7 {1s} Bb8 {0s}
142. Kd8 {1s} Ba7 {0s} 143. Kc8 {3s} g4 {3s} 144. Kd8 {26s}
Bb8 {0s} 145. Ke7 {1s} Ba7 {0s} 146. Kf6 {1s} Bb8 {0s}
147. Ke5 {1s} Ba7 {0s} 148. Kd4 {1s} Bb8 {0s} 149. Kc3 {1s}
Ba7 {0s} 150. Kb4 {1s} Bb8 {0s} 151. Ka3 {2s} Ba7 {0s}
152. Ka4 {1s} Bb8 {0s} 153. Kb4 {1s} Ba7 {0s} 154. Kc3 {7s}
Bb8 {0s} 155. Kd4 {1s} Ba7 {0s} 156. Ke5 {1s} Bb8 {0s}
157. Kf6 {2s} Ba7 {0s} 158. Ke7 {3s} Bb8 {0s} 159. Kd8 {2s}
Ba7 {0s} 160. Kc8 {1s} g3 {17s} 161. Nxg3+ {2s} Kg1 {2s}
162. Ne2+ {2s} Kh1 {0s} 163. Kd8 {31s} Bb8 {0s} 164. Ke7
{1s} Ba7 {0s} 165. Kf6 {1s} Bb8 {0s} 166. Ke5 {1s} Ba7 {1s}
167. Kd4 {2s} Bb8 {1s} 168. Kc3 {1s} Ba7 {0s} 169. Kb4 {2s}
Bb8 {1s} 170. Ka3 {1s} Ba7 {0s} 171. Ka4 {1s} Bb8 {0s}
172. Kb4 {1s} Ba7 {0s} 173. Kc3 {1s} Bb8 {1s} 174. Kd4 {2s}
Ba7 {0s} 175. Ke5 {1s} Bb8 {1s} 176. Kf6 {2s} Ba7 {0s}
177. Ke7 {1s} Bb8 {0s} 178. Kd8 {1s} Ba7 {0s} 179. Kc8 {5s}
Bb8 {2s} 180. Kxb8 {2s} Bf3 {5s} 181. Rxf1+ {6s} Ng1 {6s}
182. Rxg1# {3s} *
I did not find the solution myself (neither could my engine). The solution
(shown as the main line in the above PGN) was given by a poster to the German
CSS forum. Because the search engine of the forum doesn't seem to work right
now, I can unfortunately not cite his name.
Regards,
Dieter
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