[om] OM Floats (XML Representation)

Bill Naylor Bill.Naylor at mcs.vuw.ac.nz
Fri Nov 28 02:03:04 CET 2003


First I would like to say that I support David's suggestion for double
precision special values.

Second I would like to raise a bug/query regarding the NaN symbol in the
cd nums1. Both the CMP and FMP state that NaN \neq NaN. It also say in the
definition "See IEEE standard for floating point representations."

At http://www.w3.org/TR/xmlschema-2/#double, we are told

"The double datatype corresponds to IEEE double-precision 64-bit floating
point type [IEEE 754-1985]."

we are also told

"Not-a-number equals itself and ..."

It seems to me there is some inconsistency here. Should we change the FMP
& CMP to follow the W3C Schema people, or should we stay as is? I've
always thought the inequality a bit suspect, though I'm not entirely
convinsed on the equality. Couldn't you then go

1) NaN = NaN
2) => NaN+1 = NaN+1
3) => NaN+1 = NaN
4) => 1 = NaN - NaN
5) => 1 = 0

Maybe we should just say that equality is not defined on NaN?



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