Re: Motion 31: V04.2 Revision of proposed Level 1 text: Dot Product
On 2012-02-07 11:35:14 -0500, Michel Hack wrote:
> John Pryce wrote:
> > Ulrich: on reflection I agree with Vincent. However useful the dot product
> > is, it is essentially more complicated than +, -, *, /. I think calling
> > it "basic" will cause more disagreement than agreement, so I have removed
> > it from those lists.
>
> Two things.
>
> (1) I seem to recall that the PAR mentions "dependable computing"
> as well as "Interval Arithmetic", and
It doesn't seem so:
5.2 Scope: This standard specifies basic interval arithmetic (IA)
operations selecting and following one of the commonly used
mathematical interval models. This standard supports the
IEEE-754/2008 floating point types of practical use in interval
computations. Exception conditions will be defined and standard
handling of these conditions will be specified. Consistency with the
model is tempered with practical considerations based on input from
representatives of vendors and owners of existing systems. The
standard provides a layer between the hardware and the programming
language levels. It does not mandate that any operations be
implemented in hardware. It does not define any realization of the
basic operations as functions in a programming language.
> (2) didn't Motion 9 -- which passed -- require inclusion of Exact Dot Product?
Motion 9 is different to what is proposed in V04.2. It is about a
complete format, which is not currently specified in the current
P1788 draft. Also, even if such a complete format is specified,
this doesn't mean that it will be required. Also, it isn't as
simple as described with a large exponent range, such as around
[-2^31,+2^31].
Now, a complet arithmetic is just some form of multiple-precision
fixed-point arithmetic.
BTW, http://grouper.ieee.org/groups/1788/private/Motions/Motion0009.html
is incorrect HTML: everything appears in the title because there is
no closing </title> tag (apparently due to HTML5 parsing rules).
--
Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <http://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)