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Subject: Re: WAC018 position and WCrafty-17-12.exe

Author: Heiner Marxen

Date: 13:02:24 01/09/01

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On January 09, 2001 at 13:59:59, Larry Griffiths wrote:

>[D]R7/P4k2/8/8/8/8/r7/6K1 w - -
>
>Hopefully this position will show up visually.
>
>I have been testing my minmax again and using Crafty's perft command to verify
>the possible moves at each ply.  I entered this WAC018 position using setboard
>in crafty.  Crafty and I match until ply 5.
>
>Crafty gets...
>
>White(1): perft 1
>total moves=9  time=0.00
>White(1): perft 2
>total moves=147  time=0.00
>White(1): perft 3
>total moves=2335  time=0.00
>White(1): perft 4
>total moves=39892  time=0.03
>White(1): perft 5
>total moves=731140  time=0.58
>White(1):
>
>My program gets...
>
>Ply ---CAPTURES-- -----MOVES----- -----TOTAL-----
>  1             0               9               9
>  2            11             136             147
>  3            31           2,304           2,335
>  4         1,934          37,958          39,892
>  5        12,323         718,979         731,302
>
>Bob, have you discovered any move generation bugs in crafty since 17.12?
>I will be looking at my move generation code for bugs, but I wonder if anyone
>else can confirm if 731,140 or 731,302 is correct.
>
>Thanks in advance,
>Larry.

Chest gets:

dep          #nodes     quot        sum nodes
  0               1 [  0.000]               1
  1               9 [  9.000]              10
  2             147 [ 16.333]             157
  3            2335 [ 15.884]            2492
  4           39892 [ 17.084]           42384
  5          731140 [ 18.328]          773524

This confirms crafty.
Sorry, but your program appears to have a bug.
But you should be able to find the critical point simply by trying
the positions with one more move and see in which branch where your program
and crafty disagree.

Heiner



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