Re: Arguments for supporting Motion P1788/0023.01:NoMidRad
I strongly agree with Nate. I've seen enough evidence in the field of numerical linear algebra using interval arithmetic - both standard and mid-rad representations - that have convinced me that, in this field at least, mid-rad is the best choice. Leaving it as a sort of "outcast interval arithmetic" would not be wise for the scientific community, specially considering that numerical linear algebra is at the core of large-scale scientific applications.
Rudnei
2010/9/14 Nate Hayes
<nh@xxxxxxxxxxxxxxxxx>
Dan Zuras wrote:
Date: Tue, 14 Sep 2010 22:41:10 +0200
From: Arnold Neumaier <Arnold.Neumaier@xxxxxxxxxxxx>
To: rbk@xxxxxxxxxxxxx, 1788 <stds-1788@xxxxxxxxxxxxxxxxx>
Subject: Arguments for supporting Motion P1788/0023.01:NoMidRad
Ralph Baker Kearfott wrote:
>
> The motion has been put forward by Arnold Neumaier (through Dan Zuras),
I didn't forward the motion. I only suggested a wording for this motion,
which was put forward by Dan Zuras.
> and has
> been seconded by Nate Hayes. The discussion period therefore begins,
> and will
> continue until after the end of Tuesday, October 5.
>
> Juergen: Please post this information on the web page.
>
> William: Please record this in the minutes.
>
> The motion is as follows:
> ----------------------------------------------------
>
> The standard shall not support a midrad interval format or
> nonstandard intervals, beyond providing conversion support,
> approximately to the extent specified in the Vienna Proposal.
>
> ----------------------------------------------------
>
. . .
It appears both here & in a private email that Arnold
really means to bind us rather than the user here.
It is his interpretation that "The standard shall not
support midrad..." means "The 1788 standards committee
shall not support midrad...".
...
I cannot think of any further textual change to the
motion that embodies this. Let that be the intended
interpretation for the motion as it stands.
I accept that as a 'friendly interpretation'.
Comments, anyone?
After listenting to the exchanges the past two days, this is also my conclusion of Arnold's position, i.e., he does not oppose that users and implementers should use mid-rad or Kaucher arithmetic, just that these aspects of interval arithmetic should not be supported or endorsed by P1788.
If enough people in P1788 feel so strongly about this as does Arnold and wish to prohibit mid-rad or Kaucher arithmetic, this is fine with me and I would continue to help build such a standard.
However, what is NOT fine with me is that P1788 should then continue under the pretense that it is creating a standard for "interval arithmetic." Clearly mid-rad and Kaucher arithmetic are "interval arithmetic," and no amount of brow-beating will change this fact.
So in that case, the name of the standard and of this working group should change if this motion passes.
Of course, I do not agree with Arnold's views and positions on mid-rad and Kaucher arithmetic. In particular, his assertion:
"1.4. No strong case has been made that ... nonstandard arithmetic
is actually more efficient on a significant class of problems than what
can be done without it."
Perhaps he does not care about industries such as CAD, CAM, computer graphics, etc. where fast processing of polynomial b-splines and NURBS is essential foundation of almost all computations. But these do represent global, multi-billion dollar industries and with the proper hardware support the Kaucher arithmetic will always be faster than a processor supporting only textbook intervals as he advocates. This subject has already been examined and discussed at length in this forum and also in the position papers Arnold mentions; so I will refer to those rather than taking time to repeat an elaboration of this topic again.
Sincerely,
Nate Hayes