An additional thought Re: Some thoughts on Motion 19 (still under vote)
Paul, P-1788,
Yes, and I indeed had known that (but perhaps forgotten). I'm not
sure about staggered arithmetic, though, and it's becoming
more visible. (There also had been a thread discussing variable
precision.)
Nonetheless, the most common, in my perception, view of 754 is the
plain 64-bit binary arithmetic. Furthermore, the "keep to 754"
motion was withdrawn, with more "no" votes than "yes." Thus, previous
actions of this working group do not fetter us with regard to 754. A possible
final 1788 standard might specify two 754 64-bit binaries to represent
intervals. That would lead to a particularly simple standard, but would
not give even minimal specifications for other arithmetics. Another possibility
would be to have interval types corresponding to each 754 data type. All of this
has been discussed in relation to 1788, if not on this mailing list, by
smaller groups. An even more complex standard would involve all of the
754 data types, and additionally explicitly specify both inf-sup and mid-rad.
I think motion 19 was meant to be a compromise to maintain some level of
simplicity while providing minimal specifications to other arithmetics
that may be common. The committee needs to decide whether or not
we need to do that and whether or not motion 19 accomplishes that.
Baker
On 9/16/2010 03:47, Ralph Baker Kearfott wrote:
Thank you, Paul.
Baker
On 9/16/2010 03:25, Paul Zimmermann wrote:
Baker,
In particular, if I recall correctly, one of the items the
small (not posted to this mailing list) group discussed prior
to formulating the motion was minimal standards for arithmetics
that were not based on IEEE 754, such as multiple precision
arithmetic [...]
do you believe that multiple precision arithmetic is not covered by IEEE 754?
In that case, I suggest you read Section 3.7 of IEEE 754-2008.
Paul Zimmermann
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