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Subject: Re: Avoid move position (baron bug)

Author: Uri Blass

Date: 01:47:47 01/10/03

Go up one level in this thread


On January 10, 2003 at 04:36:28, Richard Pijl wrote:

>On January 09, 2003 at 16:51:32, Will Singleton wrote:
>
>>>If I force Qxa2 in the Baron, it takes (on a PII-500) about 8 minutes to show a
>>>good score for white. Before that the score was drawish:
>>>
>>> ply       time     nodes  score  pv
>>>
>>> 13(21).    146  14006096      0  b1a1 a2b3 e1b1 b3c2 b1c1 c2b3 c1b1 <rep>
>>> 14(23)+    239  22183609     35  b1a1 a2b3 e1b1 b3c2 b1c1 c2d2 e2d2 f6g4
>>> 14(24)&    484  42965262    120  b1a1 a2b3 e1b1 b3c2 b1c1 c2c1 d2c1 f6g4
>>> 14(24).    638  55906104    120  b1a1 a2b3 e1b1 b3c2 b1c1 c2c1 d2c1 f6g4
>>
>>Richard,
>>
>>You must have a problem here.  8 min is way too long.  Perhaps a problem with
>>repetition and hash.
>>
>>[D]r3r1k1/pbpp1pp1/1p3n1p/8/2PPp3/2P1P1P1/q2BQP1P/1R2RBK1 w - -
>>
>>Amateur shows +1.7 in 8 secs:
>>
>>8 -201 163 584342 c5 d6 cxd6 cxd6 Bg2 Ba6 Qd1 Bd3
>>9 -182 425 1508721 c5 Bc6 Ra1 Qe6 cxb6 cxb6 Bg2 d5 Ra6
>>9 0 433 1561526 Ra1 Qc2 Rc1 Qb3 Rb1 Qc2 Rc1
>>10 0 443 1660070 Ra1 Qc2 Rc1 Qb3 Rb1 Qc2 Rc1
>>11 0 479 1853613 Ra1 Qc2 Rc1 Qb3 Rb1 Qc2 Rc1
>>12 81 654 2681634 Ra1 Qc2 Rc1 Qb3 Be1 d5 c5 Kf8
>>13 177 819 3718292 Ra1 Qc2 Rc1 Qb3 Be1 Nd5 Rb1 Nxc3 Rxb3 Nxe2 Bxe2 Bc6 d5 Bb7
>>14 224 1161 5927341 Ra1 Qc2 Rc1 Qb3 Be1 Nd5 Rb1 Nxc3 Rxb3 Nxe2 Bxe2 d5 Ra3 dxc4
>>Rxa7
>>
>
>I'm not sure it's a bug. Repetition detection has been a problem some time ago
>but I think I corrected that. Also the fact that it finds the draw in 2 seconds
>supports that. To be sure I will check it again.
>
>Hash might be another cause. I'll try and check that as well.
>
>What worries me a little is that Amateur seems to need a lot less nodes to go to
>iteration 13 than the Baron. Amateur needs 3.7M nodes, Baron 14M nodes.

I think that the reason is that amateur failed high even before depth 13.
When you fail high it is easy to go deeper.

Uri



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