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Subject: Re: Ooops

Author: Sune Fischer

Date: 15:18:43 06/18/03

Go up one level in this thread


On June 18, 2003 at 17:20:00, Uri Blass wrote:

>On June 18, 2003 at 16:32:33, Sune Fischer wrote:
>
>>On June 17, 2003 at 14:08:26, Uri Blass wrote:
>>
>>
>>>>The problem is this:  If the position _starts_ off with 5 pieces, it will
>>>>play _perfectly_.   If it starts off with more, it might not.  IE it might
>>>
>>>Here is the relevant part of another post(without a part that can be deleted
>>>because of personal attack and with the words "from the original link" to
>>>prevent another conversation.
>>>
>>> I don't know why this conversation is still going on.
>>>The position in the diagram has 8 pieces, right? Then there's the comment
>>>from the original link:
>>>
>>>"It's funny that even if we sweep away three white pawns, both engines evaluate
>>>White's position as winning."
>>>
>>>-Tom
>>>
>>>My comments:
>>>
>>>I agree that there is no need to continue the conversation because it is clear
>>>based on the original link that the engines were wrong in tablebases position
>>>and it is also clear that they did not use the full 5 piece tablebases otherwise
>>>the problems of not finding draw score even in draw tablebases positions could
>>>be solved.
>>>
>>>I know that at least Junior does not use swindle mode and swindle mode is
>>>impossible because swindle mode means that at least one of the engines can
>>>evaluate the position correctly
>>>
>>>Uri
>>
>>Bob is right that when analyzing a 8 man position with 5 man TBs there is no
>>guarantee it will be solved, even if the PV shows only a 5 man position at the
>>end, all depends how deep the TBs are probed in the search.
>
>The point was not about the pv.
>Here is the quote again:
>"It's funny that even if we sweep away three white pawns, both engines evaluate
>White's position as winning"
>
>It seems clear to me that the author talks about the position after white lose 3
>pawns and not about the pv.

It does sound that way.
I guess there is no excuse then.

>>
>>Problem is often that the line is not forced, for instance there is no reason
>>the king should eat the pawns and allow a mate score from the TBs.
>>
>>So if we give Shirov the benefit of the doubt, that he did install the full set
>>of TBs, then I think that is what happened. It shouldn't be too hard for others
>>to confirm though.
>
>1)Shipov and not shirov if I remember correctly(I am too lazy to look at the
>link)

yup, correct.

>2)It is clear that in another position in the link the root position was KBP vs
>KP and the programs did not evaluate it correctly so it is clear that not all
>the 5 piece tablebases were installed.

right it's position 6, "most likely due to the defects of the 5-piece tablebase"
:)

-S.
>Uri



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