Re: Decorated intervals ARE intervals...
John, P-1788,
Can someone clarify what "severe storage and communication penalties"
means? For example, my naive software implementation of decorations
would be to tack on an integer (in whatever format is most efficient
for the machine) to the two doubles. If it is a 2-byte integer, the
storage penalty would be 2/(16+2) < 12 percent. Tacking on an extra
8 bytes (wasteful from the point of view of storage, but conceivably
logical to do in some circumstances), the storage penalty would be
< 34 percent.
In my own work, reliability and predictability of the interval
operations has usually (but not necessarily always)
trumped speed of the raw arithmetic. What is the experience of
others?
Baker
On 07/02/2011 08:49 AM, John Pryce wrote:
Dan& all
On 2 Jul 2011, at 01:04, Dan Zuras Intervals wrote:
I have stated this before& the current discussion only
strengthens my opinion that decorated intervals should
BE intervals. Full stop. Certainly at level 1 but as
far down as we can push it as well.
It would be nice if the standard could take that view, but what about the "17-byte problem"?
I.e., decorating the most popular kind of interval (a pair of doubles)
looks as if it
incurs severe storage and communication penalties.
That's why the decoration system includes the Hayes/Neumaier "bare object arithmetic"
scheme, which otherwise would be pointless.
As someone who has long experience of how computer systems evolve, will you hazard
to predict whether the 17-byte problem will be solved by hardware
advances or software
advances (so we needn't worry about it much); or will continue to be a
problem?
John
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