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Subject: Re: 6 man tabelbases.

Author: margolies,marc

Date: 13:27:20 11/07/03

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I am familiar with the text that you posted in the response.
My reading of the text regards 5-pc sets. Also it considers design failures of
engines which are not under consideration in this thread.
Therefore I do not how to directly apply the text to our discussion because I
cannot be sure what is still topical here, although I can draw some inferences
that engine design is definitely an issue in the employment of large tablebases,
that requiring a new unavailable base may not make the engine stupid.
Is there more to say about it than this?



On November 07, 2003 at 11:48:08, Javier Ros Padilla wrote:

>On November 06, 2003 at 13:45:45, margolies,marc wrote:
>
>>wow, that's intersesting. I suppose that if there are exchanges before promotion
>>it's ok.
>>I am wondering if your outcome of success was predicated on the kind of position
>>you examined or if the answer is universal.
>>
>>
>>On November 06, 2003 at 04:12:29, Javier Ros Padilla wrote:
>>
>>>On November 05, 2003 at 19:22:33, margolies,marc wrote:
>>>
>>>>if you only plan to download 2 6pc-EGTBs, then avoid chosing a base with a P in
>>>>the name-- because it refers to other bases after pawn promotion thus making it
>>>>unusable without subtables.
>>>
>>>I think you can use them without subtables, after promotion the engine and the
>>>available tablebases must help in normal play.
>>>
>>>For example with the KRPP-KR tablebase 4.7 Gb you can analyze a single position
>>>without consulting the subtables.
>>>
>>>Javier Ros
>>>
>>>
>>>>
>>>>
>>>>On November 05, 2003 at 18:11:52, Torstein Hall wrote:
>>>>
>>>>>I planned to download one or two  6 man tabelbases if I can find any. Is there
>>>>>one or two I should prefer?
>>>>>
>>>>>Torstein
>
>see this text extracted from
>
>http://www.aarontay.per.sg/Winboard/Winboard3.html
>
>author Aaron Tay
>
>[C.7] How many tablebases do I need? Can I download only some of them?
>
>The more tablebase files you install, the stronger the program will be. However,
>a full set of 3,4 and 5 Tablebase files takes about 8 GB of Hard disk space!
>Most people download a full set of 4 Piece databases and select only a few of
>the 5 pieces.
>
>Generally the 5 piece endgames with rooks are reached most frequently and should
>be downloaded . However, there are some pitfalls that you should be aware of.
>
>If you want to use the KRPKR tablebase [and assuming you have all the 3 and 4
>tablebases], make sure that you have the following endgame tablebases as well,
>KQRKR, KRBKR, KRRKR, KRNKR, . This is to ensure that the promotion cases are
>included.
>
>If you lack say the KQRKR tablebase, some programs refuse to queen the pawn in
>the KRPKR even if that would lead to a win, because such a move, would cause the
>program to drop from a position flagged as "win", to a position that is
>uncertain since they lack the relevant endgame table.
>
>A similar problem can result if you download only the KQPKQ tablebase without
>KQQKQ , KQRKQ etc..
>
>Some programs like Crafty and Yace are "smart" enough to avoid this problem, but
>most like Amy , or The Crazy Bishop cannot handle this.
>
>Also take note that not all programs support all the Tablebases. Yace for
>example, currently does not use the 4+1 tablebases [ King and 3 pieces/pawns on
>a side versus a alone King] , because such positions are easily won most of the
>time barring rare cases [Like double rook pawns, wrong coloured bishop and King
>vers King]. Also I think only Crafty currently, supports 6 piece tablebases.
>Szots Gabor also reports that Wildcat , Capture and perhaps Inimichess cannot
>handle incomplete 5 men tablebase
>
>
>           Javier Ros



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