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Subject: Re: Topalov-Svidler Corus 2004 Rd 7 (Yace PB)

Author: Gabor Szots

Date: 05:44:41 01/19/04

Go up one level in this thread


On January 19, 2004 at 02:24:03, Kurt Utzinger wrote:

>On January 18, 2004 at 17:58:26, Dieter Buerssner wrote:
>
>>On January 18, 2004 at 15:59:46, Ricardo Gibert wrote:
>>
>>>On January 18, 2004 at 15:40:47, Kurt Utzinger wrote:
>>>>14+  01:54 -2.63   Ke8 Qc4 Kd7 Rd1+ Ke8 Rd5
>>>
>>>The -2.63 score of the last PV starting with Ke8 got me curious. How come so
>>>negative? But then I noticed that the last move Rd5 is nonsense. What happened
>>>to Yace here?
>>
>>Note the "14+". This means, that the engine reported a score as "lowerbound". It
>>was outside the search window. Many (most) engines will not show a PV in this
>>case at all. Yace tries to show something - often it is stupid (by design). I
>>thought, it is better than nothing. To have the typical output of other engines,
>>just ignore any PV after depth+/depth-. I did not look at this specific PV. It
>>should mean, however "I guarantee you, that with depth 14, I will get a score
>>not worse than -2.63. How much better the score will turn out, I don't know yet.
>>The PV fragment I show here, should be enough to convince you, that my score
>>really is better than -2.63. This does not mean, that for examply Rd5 is the
>>best move. But it should mean, I tried all moves (instead of Rd5), and no one
>>helped to bring the score back to -2.64 for the opponent.
>>
>>Regards,
>>Dieter
>
>     Hi Dieter
>     Many thanks for your interesting explanation that will help
>     us to better understand what's your engine is doing.
>     Kurt

I agree. This is the first time I am expleined what these signs after depth
mean, although I am not still uncertain about the negative sign (does it mean
upperbound, i.e. this is a move by which the score will not improve above what
is displayed?).

Gábor



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