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Subject: Re: evaluation of rybka is not very close to fruit.

Author: Ryan B.

Date: 02:48:28 02/18/06

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On February 18, 2006 at 05:23:42, George Tsavdaris wrote:

>On February 18, 2006 at 03:35:23, Uri Blass wrote:
>
>>On February 17, 2006 at 20:03:41, William Penn wrote:
>>
>>>I won't try to give examples here, but my impression is like Vincent's. I
>>>regularly compare long analysis from Fruit and Rybka in infinite mode (usually
>>>several hours run time) and their evaluations are remarkably similar, in
>>>general. I haven't noticed any major exceptions. But that's just my impression,
>>>I haven't researched or quantified it.
>>>WP
>>
>>
>>My impression is different based on analysis of correspondence games.
>
>Yes, i also have the same impression with you.
>
>But what is really important is what you said in another post:
>Rybka is missing endgame knowledge that Fruit already has. So i don't think
>there is anyone believe _and if we assume that Rybka is a Fruit-clone_ that
>Vasik actually removed the endgame knowledge Fruit has. As you have shown in
>some endgames, Fruit understands the positions while Rybka not due to missing
>knowledge.
>That can't be explained in another way than the obvious.....
>


Just a quick note, Gambit Fruit had less endgame knowledge than Fruit 2.1.


>
> Also William says about REMERKABLE similarities. All these are simple words
>with no meaning, until he posts the positions that he has seen these remarkable
>similarities as i haven't find any until now....
> Vincent did the same. Why he doesn't post the "0.1 position" in order to let us
>see the truth instead of only hearing it.....?
>
>
>>
>>I clearly see cases of disagreement and it is not that one is always right.
>>
>>difference of more than 0.5 pawns is significant difference and there were cases
>>when I saw it in practical analysis.
>>
>>The position that I gave is not from my correspondence games but from analysis
>>of one of my tournament games when rybka understand immediatly that black is
>>better and fruit see score that is close to draw (even at depth 3 that is
>>probably depth 5 of other programs because i do not believe vasik's information
>>about depth).
>>
>>I think that if you try unbalanced positions when one side has passed pawns and
>>the other side has material compensation then you can see often significant
>>difference between fruit and rybka and unbalanced positions happen.
>>
>>In one case there was no significant difference in evaluation but there was a
>>significant difference in the suggested move and I believe that rybka's move was
>>simply better.
>>
>>It is important to choose the better move when the evaluation of many moves is
>>almost the same.
>>
>>Uri



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