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Subject: Re: Mate in 16 mystery

Author: Uri Blass

Date: 07:36:49 09/04/03

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On September 04, 2003 at 10:33:23, Dana Turnmire wrote:

>On September 04, 2003 at 10:30:51, Uri Blass wrote:
>
>>On September 04, 2003 at 10:20:40, Dana Turnmire wrote:
>>
>>>In the following position Chess Genius 7 cannot find mate after many hours of
>>>analysing yet Chessmaster 9000 finds mate in 16 INSTANTLY.  What gives?
>>>[d] 4r1r1/bB4p1/8/2p1kPKn/n7/3R4/3P4/2B5 w - -
>>
>>Movei is in the middle
>>
>>The developement version can see the mate in 16 but not instantly
>>
>> 12 9969 3462 6849879 d3d5 e5e4 d5d7 e4e5 c1a3 c5c4 a3d6 e5d4 d6f8 d4e5 d7d5 e5e
>>4 d5d8 e4e5 d8e8 e5d4 e8d8 d4e5 d8d5 e5e4 d5d7 e4e5 f8d6 e5d4 d6b4 d4e5 d2d4 c4d
>>3 d7e7 e5d4 e7e4
>> 12 9969 3953 7808564 d3d5 e5e4 d5d7 e4e5 c1a3 c5c4 a3d6 e5d4 d6f8 d4e5 d7d5 e5e
>>4 d5d8 e4e5 d8e8 e5d4 e8d8 d4e5 d8d5 e5e4 d5d7 e4e5 f8d6 e5d4 d6b4 d4e5 d2d4 c4d
>>3 d7e7 e5d4 e7e4
>>
>>A previous version that is slightly better because it is faster in nodes per
>>second says:
>>
>> 12 9969 2637 7316683 d3d5 e5e4 d5d7 e4e5 c1a3 c5c4 a3d6 e5d4 d6f8 d4e5 d7d5 e5e
>>4 d5d8 e4e5 d8e8 e5d4 e8d8 d4e5 d8d5 e5e4 d5d7 e4e5 f8d6 e5d4 d6b4 d4e5 d2d4 c4d
>>3 d7e7 e5d4 e7e4
>> 12 9969 2922 8114929 d3d5 e5e4 d5d7 e4e5 c1a3 c5c4 a3d6 e5d4 d6f8 d4e5 d7d5 e5e
>>4 d5d8 e4e5 d8e8 e5d4 e8d8 d4e5 d8d5 e5e4 d5d7 e4e5 f8d6 e5d4 d6b4 d4e5 d2d4 c4d
>>3 d7e7 e5d4 e7e4
>>
>>Uri
>
>There is obviously some kind of defect in the evaluation function of Genius 7.
>How else can this be explained?

I think that it is search and not evaluation.
By limiting extensions it is easy practically never to solve it.

I forgot to mention the hardware that I used for movei and it was A1000.
The time that it needs is near 30 seconds on that hardware.

Uri



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