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Subject: Re: TB's & Castling (Opps, I did post the wrong FEN)

Author: Slater Wold

Date: 21:42:56 03/06/02

Go up one level in this thread


On March 06, 2002 at 23:40:28, Robert Hyatt wrote:

>On March 06, 2002 at 22:49:38, Slater Wold wrote:
>
>>On March 06, 2002 at 22:27:17, Uri Blass wrote:
>>
>>>On March 06, 2002 at 19:18:16, Slater Wold wrote:
>>>
>>>>Hyatt said in an earlier post that TB's don't take into account the ability to
>>>>castle because it would be a waste.
>>>>
>>>>However, when I feed this position into any engine, it solves it in 0.00 as a TB
>>>>win.
>>>>
>>>>[D]5Q1Q/5Q1Q/5Q1Q/5Q1Q/8/6P1/6k1/4KR1R w K -
>>>
>>>Your FEN is wrong and we need to imagine that all the white queens that you
>>>copied from dann corbit's post are missing.
>>
>>
>>You're right.  But obviously this is not the position I am talking about,
>>because I don't have the 13 man TB's.  :)
>>
>>
>>>>It shows 20 possible moves, all from TB's I am guessing.
>>>>
>>>>I cannot cut and paste the eval, because there isn't one, but I have:
>>><snipped>
>>>>1.+ - (#4) Rf4
>>>
>>>This is not correct and the program that you use has bugs.
>>>It should not call tablebases in a position that is not in the
>>>tablebases(castling is legal)
>>>
>>> >_Several_ of these moves take castling into accout.
>>>>
>>>>After Rf4 Kxg3 my TB's show 28 moves.  The first move is 1. + - (#2) O-O, the
>>>>last is 28. + - (#15) Rh8.
>>>>
>>>>I am 100% sure TB's do indeed take castling into consideration.
>>>
>>>
>>>No
>>>You do not understand how tablebases work.
>>>There are no moves in tablebases.
>>>
>>>The engine generates all the legal moves and looks in the tablebases after these
>>>moves to see distance to mate.
>>
>>
>>Um, well, according to Hyatt, it would tell the TB "o-o" and it wouldn't return
>>anything.  I am very well aware how TB's work.
>
>Not quite.  First I _never_ said anything like that.  With EGTB's you don't
>give them a move, and get back a score, you give them a _position_ and you get
>back a score.  And the score says "mate in N from the given position,
>assuming castling is impossible."
>
>
>
>>
>>
>>>If castling is legal then the engine looks at the tablebases to see the distance
>>>to mate after castling in order to see the mate in 2 score.
>>
>>
>>According to Hyatt, no it doesn't.
>
>
>You are greatly twisting things around.  Re-read what Uri wrote...
>
>"if castling is legal then the engine only checks the TB _after_ castling
>has been done."  Because after castling has been done, it can't be done again
>and the resulting EGTB score will be correct.  Prior to castling, the score
>will be wrong because castling is possible but the EGTB scores don't include
>castling.
>
>
>
>
>>
>>
>>>Uri
>>
>>The correct position is:
>>
>>[D]8/8/8/8/8/6P1/6k1/4KR1R w K -
>>
>>Sorry.

I am not trying to "twist" anything around.  You said TB's don't take into
account castling.  Ok, fine.  I believe you.  I open a chess engine, and it's
returning o-o as a TB move.  NO EVAL NEEDED.  I am asking a simple question.
Why?!  How is an engine returning a mate, without TB's, without an eval?

If it's a stupid question, I apologize.  I just don't understand, obviously.



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