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Re: [Stds-754] IEEE 754 Revision, comments from IFIP WG 2.5
Wouldn't it be much more useful to have the interval arithmetic
community
standardize their primitive operations: add_interval(u,v), etc.
Without pinning these representations, operations, and exceptions
for intervals, I don't see that we would be providing much useful
guidance.
Cheers,
Jeff
2. Rounding alternatives (6. Modes and rounding)
Of interest to the numerical community is the use of interval
arithmetic. In order to obtain as narrow intervals as possible, it is
necessary to have directed rounding in hardware.
The standard permits switching of rounding mode at the systems level,
either in constant-mode or in dynamic mode. Doing interval arithmetic
will then require switching the rounding mode almost after every
arithmetic operation, which will take a lot of time. For further
information see the letters from Ulrich Kulish of May and August,
2005, and June 2006.
We would therefore prefer to have operations like
AddBinaryRoundingDirectionTowardPositive(a,b) and
AddBinaryRoundingDirectionTowardNegative(a,b), as well as similar
for the other elementary operations, also available.