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Subject: Re: an interesting bug in my move generator

Author: Heiner Marxen

Date: 10:25:44 01/01/02

Go up one level in this thread


On January 01, 2002 at 13:03:47, Gian-Carlo Pascutto wrote:

>On December 31, 2001 at 21:06:49, Heiner Marxen wrote:
>
>>On December 31, 2001 at 17:07:31, Uri Blass wrote:
>>
>>>My program had problems with WAC 250 so I decided to ask it to calculate the
>>>perft function and found that it cannot calculate perft 4 correctly
>>>
>>>The bug is that my program believed that double check from 2 rook directions is
>>>impossible
>>>
>>>Here is the position of WAC 250
>>>[D]1b5k/7P/p1p2np1/2P2p2/PP3P2/4RQ1R/q2r3P/6K1 w - - 0 1
>>>
>>>When I asked my program to calculate perft it failed in perft 4.
>>>
>>>My program did not count correctly the number of moves after
>>>1.a5 Ng8 hxg8Q+
>>>
>
>Sjeng: perft 4
>Raw nodes for depth 4: 1353197
>Time : 0.93
>
>Sjeng: perft 5
>Raw nodes for depth 5: 40590029
>Time : 11.97
>
>Are these numbers correct?
>
>--
>GCP

Chest agrees with your numbers:

FEN: 1b5k/7P/p1p2np1/2P2p2/PP3P2/4RQ1R/q2r3P/6K1 w - -
Counting width of legal tree, 5 plies deep...
Time (user) = 9.84 sec
dep          #nodes     quot        sum nodes
  0               1 [  0.000]               1
  1              31 [ 31.000]              32
  2            1213 [ 39.129]            1245
  3           35927 [ 29.618]           37172
  4         1353197 [ 37.665]         1390369
  5        40590029 [ 29.996]        41980398

(Done on a K7/600)

Cheers,
Heiner



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