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RE: xml datatype facets

From: Kirkham, Pete (UK) <pete.kirkham@baesystems.com>
Date: Thu, 13 Jan 2005 12:35:20 +0000
To: www-rdf-interest@w3.org
Cc: Jeremy Carroll <jjc@hplb.hpl.hp.com>, Geoff Chappell <geoff@sover.net>
Message-id: <820DBA1A8ECA1D45A557AFD03CF4DEE06E5046@glkms0015>


With reference to http://www.w3.org/2001/sw/BestPractices/XSCH/xsch-sw-20041216/ 3.2.2

Conventionally in engineering the value '4.0' without any further error information denotes the interval [3.95, 4.05), whereas "4.0"^^ieee:float denotes [4 * (1 - 2^-25), 4 * (1 + 2^-25)) or so, so the float usually implies the decimal but not the other way round. The interval for a double is always a sub-interval of a float, so "4.0"^^ieee:float may be inferred from "4.0"^^ieee:double, but not the other way round. This is a reverse of xsd:decimal, which is taken as exact, so is suitable for accountancy.

There is a trend in technical computing towards use of interval arithmetic for calculations to allow the effects of these approximations to be correctly propagated to the results.

Does anyone know of a datatype for engineering values (either real intervals, or quantities with both a real interval and a units of measure facet)?


Pete






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Received on Thursday, 13 January 2005 12:35:34 GMT

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