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[Bug 11531] precisionDecimal terminology

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Date: Fri, 10 Dec 2010 22:07:09 +0000
To: www-xml-schema-comments@w3.org
Message-Id: <E1PRB7N-0005qT-TL@jessica.w3.org>

--- Comment #1 from Dave Peterson <davep@iit.edu> 2010-12-10 22:07:09 UTC ---
(In reply to comment #0)
> There is a mismatch between the terminology of XSD 1.1 part 2 regarding
> precisionDecimal, and the terminology of IEEE 754 - 2008. In particular, the
> term "precision" is used in a quite different way. In XSD 1.1 it is used to
> mean (essentially) the exponent when the significand is treated as an integer,
> while in IEEE it is used to mean the (maximum) number of digits in the
> significand.

It's expressed in terms of the exponent, but what it means is the number of
digits to the right of the decimal  point in the significand.  (Both of us
conflating the significand as a number and as a string of decimal digits, a
numeral).  The number of digits to the right of the decimal point is often
called precision as well--corresponds to "plus or minus xx", which, if you wish
terminology to differentiate that from precision such as "plus or minus xx
percent", is quite properly called arithmetic precision.  The "precision" that
IEEE is describing is related in a complicated way to both of these two kinds
of precision.

More comments to come.  (Surprise!  ;-)  )

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Received on Friday, 10 December 2010 22:07:11 UTC

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