Re: Encodeing of compressed intervals
On Thu, 26 Jun 2014 21:05:53 -0700 (PDT), Dima wrote:
> It is necessary to define Level 3 representation of compressed
> intervals before definition of their bit-encoding and octet-encoding.
> Now I defined it as disjoint sum (C union)
> Level 3 representation = FP x FP + DEC
Dima, I don't understand why you want to complicate things by invoking
unions or similar constructs. Yes, there are many way to encode all
sorts of things in a bitstring that starts with the representation of a
NaN -- but is there any doubt that (in a 754-conforming implementation)
a compressed interval simply consists of two floating-point datums, for
non-empty bare intervals as well as for threshold-crossing decorations?
Remember that octet-encoding only applies to *single* datums, because
it is at that level that Endianness issues are defined -- NOT across
a bitstring that may span several datums. So we *have to* encode the
compressed decoration in one of the two floating-point datums, and my
proposal avoids all those portability issues of NaNs. Read 754-2008
carefully, and you'll note that there are many SHOULDs and few SHALLs
concerning the propagation of NaNs -- there are reasons for that.
Michel.
---Sent: 2014-06-27 14:52:58 UTC