Alan Ruttenberg wrote: > > I'm sorry for the overgeneralization and didn't mean to insult. It's > just that as much as I think about it, I can't understand the idea that > the value space of floats and the value space of decimal are disjoint. > Fundamentally these represent some of the same real numbers and this > isn't reflected in the spec. In addition, many numbers that can be > finitely expressed and be calculated with find no place in *any* of the > value spaces, e.g. 1/3. It is this sense of "mathematical" that I was > referring to. The best explanation that I know of was written by Mark Reinhold, a member of the original schema WG (...and, if memory serves me, was a member of the team that wrote the Java floating-point spec). During the development of the Schema 1.0 (i.e., a few years before we went to Rec) we had MANY discussions about the numeric types, and especially about float and double. As part of that discussion, Mark wrote a note entitled "Floating-point datatypes are not real datatypes" [1] that goes into great detail on this point. It also serves as a good entry point to the archives for the discussions the WG had on these issues. pvb [1] http://lists.w3.org/Archives/Member/w3c-xml-schema-ig/1999Oct/0025.htmlReceived on Tuesday, 8 July 2008 18:25:36 GMT
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