Some Q&A with Kahan on IEEE 754

[Glyph Lefkowitz]

Huaiyu Zhu <hzhu at rocket.knowledgetrack.com> writes:

> But getting libm to work predictably across platforms is a whole
> other can of worms, above and beyond 754 support.

I don't know about the other posters here, but this seems like a more
important issue to me.  I mean, I would like to write cross-platform
code that works predictably with numbers bigger than 12 and smaller
than 7.  Currently the only way to do that (as far as I can tell) is
to surround every arithmetic operation and cmath call that involves a
user-input variable with a try: except: as WELL as testing for 4
different spellings of NaN and Inf -- and those are only the spellings
I've seen so far.  Maybe maybe MacOS X will spell it "Infinity -- a
very large number" and "Not A Number -- bad input, perhaps?" or
somesuch...

I know that the way that math works is a weighty religious issue to
some folk :) but I don't much care, so long as it works *predictably*.
I'll cheerfully work around whatever warts crop up in extreme cases,
so long it's only _one_ set of warts.

-- 
Glyph Lefkowitz
Professional -- Software Engineer,  Origin Systems
Amateur      -- Computer Scientist, Twisted Matrix Enterprises
(My opinions are my own and do not reflect in any way on the policies
or practices of my employer, etcetera etcetera.)