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Subject: Re: deduping EPD files

Author: Dann Corbit

Date: 10:58:24 02/04/99

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On February 04, 1999 at 06:32:59, Steffen Jakob wrote:
>Hi Manfred!
>
>On February 04, 1999 at 06:15:24, Manfred Rosenboom wrote:
>
>>On February 04, 1999 at 01:31:13, Robin Smith wrote:
>>
>>>There are many ways to de-dupe PGN or other game files.  Are there any similar
>>>utilities for de-dupping EPD files of duplicate positions?
>>
>>I have a lot of UNIX tools on my machine, like sort and uniq,
>>so it is very easy to remove the duplicate EPD lines.
>
>I am not completely familiar with the EPD format (any pointers?) but I think
>that it is possible to have to different string which specify the same position.
The EPD specification is a subset of the PGN Standard.
I have seen positions that are duplicates, yet appear different.  An example is
a position which has the e.p. set for some pawn, but that e.p. condition cannot
possibly affect play.  A similar row may not have it set or have a different
square set which cannot affect play.  This type of recording is specified in the
document, but I think it is a defect:
"16.1.3.4: En passant target square

The fourth field is the en passant target square.  If there is no en passant
target square then the single character symbol "-" appears.  If there is an en
passant target square then is represented by a lowercase file character
immediately followed by a rank digit.  Obviously, the rank digit will be "3"
following a white pawn double advance (Black is the active color) or else be
the digit "6" after a black pawn double advance (White being the active color).

An en passant target square is given if and only if the last move was a pawn
advance of two squares.  Therefore, an en passant target square field may have
a square name even if there is no pawn of the opposing side that may
immediately execute the en passant capture."

Can anyone tell my why we would want to mark e.p. squares that cannot possibly
have any bearing on the game?

>P.S.: BTW: you don't need "uniq" but only "sort -u". :-)
Depends upon your implementation.



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