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Re: discussion period begins, until Jan. 26: "natural interval extension": friendly amendment to M001.02

Dear Richard;

thank you for your mail. It shows me that some further clarification seems to be necessary:

What you say in the first paragraph of your mail has nothing to do with the task developing a standard for interval arithmetic. But since you explicitly ask for it, let me say it: I very much appreciate what James Demmel, Siegfried Rump, Shin ichi Oishi, Baker Kearfott, and many others have done for computer and interval arithmetic (with a tool not primarily developed for it). It is excellent work! But stating this is not our task.

A standard for interval arithmetic has to state clearly what is needed for efficient, accurate, and successful interval arithmetic and emphatically demand this from manufacturers.

Any analysis how close existing processors come to our requirements is not subject of our task. I am strictly against that representatives of processor manufacturers, they may be from Sun, Intel, IBM, or others, tell us what a standard for interval arithmetic is permitted to require. Their intention finally only can be selling us perhaps with little changes what they have already. We should not permanently be forced to approximate our needs on processors primarily developed for other purposes. Processors need to be better adapted to the needs of interval arithmetic!

Well defined and implemented interval arithmetic has a very high potential for the future of scientific computing. Developing a standard for it gives us a unique chance and the power to get it into commercial processors. Let's not miss this chance!
 
With best regards
Ulrich Kulisch

(By the way: Well defined and implemented interval arithmetic means quite a bit more than just an EDP).





Am 14.01.2016 um 17:20 schrieb Richard Fateman:
On 1/14/2016 7:48 AM, Ulrich Kulisch wrote:
Dear colleagues, 

I apologize for repeating myself.


Perhaps you could comment on
 James Demmel's recent posting in which he
refers to a nice result for the related objective of summation of
n numbers, accurately. This method can use one
or more processors such as are currently available, uses a
small number of registers, and is modestly slower than
 the obvious method for (unreliable) summation.


While your proposals are interesting, to achieve the claimed
speed would require special hardware (hardware which
is not commercially available).   So we must consider if
the EDP is worthwhile to incorporate in the 1788 standard
if it were inevitably implemented in software.  Which means
it should be compared to other software schemes such
as Demmel's  (and MPIR -- which of course does far more
than EDP).





-- 
Karlsruher Institut für Technologie (KIT)
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Prof. Ulrich Kulisch

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