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Re: What is your philosophy? Tracking or Static?

There has been a lot of discussion about tracking vs. static methodologies. IMHO, it is a bit of a red-herring to couch things in these terms. Both are applications of a single FTDIA. The only difference is how pessimism due to unrecognized interval dependence is handled in the computation.
As a low-level hardware standard, I think P1788 needs to be realistic and mindful of what it can hope to achieve. In my view, to try and standardize interval computations in such a way that the non-pessimistic (what I believe people are referring to as "static") result is always returned is simply too big a problem. If P1788 tries to do this, it will fail.
My understanding is that P1788 is essentially a low-level standard aimed at efficient hardware implementations. If this is true, P1788 should probably think very carefully about what is realistically computable at the hardware level. From my perspective, this clearly leads to the tracking methodology. 

Nate
----- Original Message ----- From: "Dan Zuras Intervals" <intervals08@xxxxxxxxxxxxxx> 
To: "Ralph Baker Kearfott" <rbk@xxxxxxxxxxxx>
Cc: <stds-1788@xxxxxxxxxxxxxxxxx>; "Dan Zuras Intervals" <intervals08@xxxxxxxxxxxxxx> 
Sent: Wednesday, May 25, 2011 6:17 AM
Subject: What is your philosophy? Tracking or Static?



Date: Tue, 24 May 2011 19:05:38 -0500
From: Ralph Baker Kearfott <rbk@xxxxxxxxxxxx>
To: Nate Hayes <nh@xxxxxxxxxxxxxxxxx>
CC: John Pryce <j.d.pryce@xxxxxxxxxxxx>,
 stds-1788 <stds-1788@xxxxxxxxxxxxxxxxx>
Subject: Re: Ar we succeeding?

All,

Does someone else also have an opinion concerning this (please)?

Baker



Baker, et al,

I find I do have an opinion on this.  And as long as Nate's
motion is in its discussion period, now is as good a time
as any to discuss it.

Let me put it in the form of a question I put to Nate:

Is your philosophy about decorations a tracking approach or
a static approach?

There seem to be two schools of thought about the meaning
of decorations.

There is the TRACKING school in which decorations are the
maximal (most pessimistic) result of the tree of evaluations
that led up to the result to which they are attached.  That
is, every exceptional or noteworthy incident in that tree is
recorded for all to see whether it is relevant to the final
result or not.

Then there is the STATIC school in which decorations are
information concerning the current result only.  Earlier
decorations may pass through to this result if they still
apply & may be discarded if they do not.  In this case the
decoration must be able to be interpreted in the context
of the final result whatever happened before.

(In either school, the decoration must be ordered WRT to
subsets of arguments.  I believe this is both necessary &
sufficient for an FTDIA to be proved.)

I asked this question of Nate because his motion seemed to
be primarily of the tracking school but with some static
features thrown in.

I think we need to be consistent on this point.  As much
for our own understanding as to explain the meaning of
decorations to the rest of the world.

I will admit that I started out in the Tracking school.
But some remarks I've heard in this forum & privately have
suggested to me that the Static school might serve us better
as a standard.

So I ask of all of you: Which philosophy should we espouse?
Tracking or Static?

I believe that once we decide this many of our more
difficult questions will fall out as obvious.

Yours,

Dan