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Subject: Re: Question for Prof. Hyatt

Author: Uri Blass

Date: 23:06:39 02/24/06

Go up one level in this thread


On February 25, 2006 at 01:04:26, Stuart Cracraft wrote:

>[D]8/7p/5k2/5p2/p1p2P2/Pr1pPK2/1P1R3P/8 b - -
>
>On February 22, 2006 at 15:38:43, Robert Hyatt wrote:
>>
>>
>>It is less about depth and more about time.  It is getting this in 10 seconds
>>using a single PIV 2.8 processor.  Part of the delay is caused by having to
>>escape the white checks with the black king, part probably caused by forward
>>pruning...
>
>A monster bug in my pawn hash table implementation screwed me up royally
>on this position. It's now solving. WAC #2 finally. This is with the
>connected passed pawns term reward set to zero also.
>
>position file? [wac.epd] wac.epd
># of test positions to test? 1
>maxtime = 18000
>Interrupt current ply and return move at timeout
>Testsuite: Tests/wac.epd 1 positions
>*** Problem   Solution(s): Rxb2 (bm)
>-- ** -- ** -- ** -- **
>** -- ** -- ** -- ** BP
>-- ** -- ** -- BK -- **
>** -- ** -- ** BP ** --
>BP ** BP ** -- WP -- **
>WP BR ** BP WP WK ** --
>-- WP -- WR -- ** -- WP
>** -- ** -- ** -- ** --
>mv 1 stage 0, black to move, computer plays black
>hash=359a65d864d93847
>pawnhash=3e87fdd09deedce8
>0 0 0 0 0 0
>Alpha=2148 Beta=2949 Maxdepth=9999999 MaxTime=18000 xboard=0
>Itr/Max Mv   Score   Time Nodes PV
> 1/ 1> b3b2 2949  0.00        2 b3b2
> 1/ 2  b3b2 6786  0.00       20 b3b2 d2b2
> 2/ 3< b3b2 6385  0.00       42 b3b2 d2b2
> 2/ 3  b3a3 2904  0.00      114 b3a3 b2a3
> 3/ 4> b3a3 3304  0.00      139 b3a3 b2a3 c4c3
> 3/ 5  b3b2 3304  0.00      215 b3b2
> 4/ 5> b3b2 3704  0.00      284 b3b2 d2b2 c4c3

You have a big bug if you evaluate the line Rxb2 Rxb2 as the best line at depth
1

At that depth it is clear that it is losing a rook for a pawn and there are
better moves.

There is also no justification to choose it at depth 3 or to choose Rxa3 at
depth 2.

It seems that for some reason your program analyze only captures a the first
plies.

Here is analysis by latest Movei
Movei see it at depth 12 after some seconds and it needs to see promotion of
black pawn to find Rxb2

setboard 8/7p/5k2/5p2/p1p2P2/Pr1pPK2/1P1R3P/8 b - -
analyze
 1 107 0 25  f6e6
 2 103 0 43  f6e6 d2g2
 2 103 0 84  f6e6 d2g2
 3 108 0 150  f6e6 d2g2 e6d6
 3 108 0 224  f6e6 d2g2 e6d6
 4 98 0 493  f6e6 h2h4 h7h5 d2g2
4 99 0 653 b3b8
 4 98 0 753  f6e6 h2h4 h7h5 d2g2
4 99 0 874 b3b7
 4 102 0 919  b3b7 d2g2 f6e6
4 103 0 1143 f6e7
 4 103 0 1217  f6e7 e3e4 f5e4 f3e4
 4 103 0 1217  f6e7 e3e4 f5e4 f3e4
 5 93 0 1669  f6e7 e3e4 f5e4 f3e4 e7e6 e4e3
5 94 0 1910 f6e6
 5 109 0 2377  f6e6 h2h4 h7h5 d2g2 e6d6
 5 109 0 2780  f6e6 h2h4 h7h5 d2g2 e6d6
 6 93 1 4619  f6e6 e3e4 f5e4 f3e4 b3b8 e4d4 b8c8
6 94 1 7630 h7h5
 6 93 1 8919  f6e6 e3e4 f5e4 f3e4 b3b8 e4d4 b8c8
 6 93 1 11460  f6e6 e3e4 f5e4 f3e4 b3b8 e4d4 b8c8
 7 86 3 14744  f6e6 e3e4 c4c3 b2c3 b3c3 e4e5 c3a3
7 87 3 17064 b3b7
 7 103 3 20593  b3b7 e3e4 f5e4 f3e4 b7e7 e4d4 e7e2 d4c3 e2e4
7 104 4 22333 b3b8
 7 103 4 24212  b3b7 e3e4 f5e4 f3e4 b7e7 e4d4 e7e2 d4c3 e2e4
 7 103 4 27352  b3b7 e3e4 f5e4 f3e4 b7e7 e4d4 e7e2 d4c3 e2e4
 8 101 7 40192  b3b7 h2h4 f6e6 e3e4 f5e4 f3e4 b7g7 e4f3
8 102 9 53455 b3b8
 8 108 10 61375  b3b8 e3e4 f5e4 f3e4 b8e8 e4d4 e8e2 d2d1 e2c2 h2h3
 8 108 12 69148  b3b8 e3e4 f5e4 f3e4 b8e8 e4d4 e8e2 d2d1 e2c2 h2h3
 9 104 20 122015  b3b8 h2h3 b8b7 e3e4 f5e4 f3e4 b7e7 e4d4 e7e2 d4c3 e2e4
 9 104 35 217306  b3b8 h2h3 b8b7 e3e4 f5e4 f3e4 b7e7 e4d4 e7e2 d4c3 e2e4
 10 107 51 324068  b3b8 d2g2 b8b7 h2h4 h7h5 g2f2 b7g7 f2d2 f6e6
 10 107 67 432948  b3b8 d2g2 b8b7 h2h4 h7h5 g2f2 b7g7 f2d2 f6e6
 11 113 162 1008871  b3b8 h2h4 b8g8 e3e4 f5e4 f3e4 g8g4 d2f2 g4h4 e4d4 d3d2 f2d2
 h4f4 d4c5
 11 113 189 1183017  b3b8 h2h4 b8g8 e3e4 f5e4 f3e4 g8g4 d2f2 g4h4 e4d4 d3d2 f2d2
 h4f4 d4c5
 12 106 264 1659869  b3b8 h2h4 h7h5 d2g2 b8b3 g2f2 b3b7 f2d2 f6e6 d2g2 e6d5
12 107 314 1976669 b3b7
 12 111 359 2286743  b3b7 h2h4 h7h5 d2g2 b7b8 g2f2 b8g8 e3e4 f5e4 f3e4 g8e8 e4f3
 f6f5 f2g2
12 112 429 2811982 b3b2
12 141 453 3042096 b3b2
 12 240 540 3690983  b3b2 d2b2 c4c3 b2b6 f6g7 b6b7 g7h6 b7b6 h6h5 b6b5 c3c2 b5f5
 h5h4 f5f6 h7h5 f6c6 d3d2 c6c2 d2d1q c2e2
 12 240 553 3778228  b3b2 d2b2 c4c3 b2b6 f6g7 b6b7 g7h6 b7b6 h6h5 b6b5 c3c2 b5f5
 h5h4 f5f6 h7h5 f6c6 d3d2 c6c2 d2d1q c2e2
13 270 646 4566480 b3b2
 13 288 770 5600318  b3b2 d2b2 c4c3 b2b6 f6g7 b6b7 g7g6 b7b6 g6h5 b6b5 c3c2 b5f5
 h5g6 f5g5 g6f7 g5c5 d3d2 c5c7 f7e6 c7c2 d2d1q c2e2
 13 288 792 5769839  b3b2 d2b2 c4c3 b2b6 f6g7 b6b7 g7g6 b7b6 g6h5 b6b5 c3c2 b5f5
 h5g6 f5g5 g6f7 g5c5 d3d2 c5c7 f7e6 c7c2 d2d1q c2e2




Uri



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