Re: Motion 31: V04.2 Revision of proposed Level 1 text
> Date: Thu, 1 Mar 2012 17:01:07 +0100
> From: Vincent Lefevre <vincent@xxxxxxxxxx>
> To: stds-1788 <stds-1788@xxxxxxxxxxxxxxxxx>
> Subject: Re: Motion 31: V04.2 Revision of proposed Level 1 text
>
> On 2012-02-29 16:37:10 +0100, Ulrich Kulisch wrote:
> > Vincent:
> >
> > Dan Zuras wrote on Febr. 13, 2012:
> >
> > >I think that P1788 should not do the job of 754...
> > . . .
> >
> >
> > In principle, I agree with whoever said 1788 should
> > not do 754 things again. And, indeed, you will find
> > the dot products& related reductions as optional in
> > clause 9.4 of 754-2008.
> >
> > Alas, we could not agree on making them mandatory&
> > we could not agree on an accuracy policy.
> >
> > So if 1788 made them both mandatory& exact (as Ulrich
> > wishes) it would not be repeating anything from 754.
>
> Well, until Draft 04.3, P1788 Level 1 conflicted with IEEE 754
> (even if the specs are different, there should not be two dot
> products defined by two different standards -- it would be bad
> if each standard defined its own floating-point dot product).
I was refering to the definition of the dot product,
not any particular style of implementation such as
complete arithmetic.
And I think if we were to make it both mandatory &
exact we would not find ourselves in conflict with
754 (which has it as both optional & of unspecified
quality). We would merely be exercising that
particular 754 option for 1788 conforming systems.
>
> > The exact dot product could just be called 'edot'. It will
> > implicitely be introduced with complete arithmetic.
>
> However complete arithmetic is something new. I see that the Level 1
> Draft 04.4 made things clear (referring to complete arithmetic, which
> was not the case before). So, currently this is fine.
>
> Regards,
>
> --
> Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.net/>
Oh, I think we can define an accurate dot product at
level 1 without reference to complete arithmetic.
More to the point I think we should.
Complete arithmetic or any other methods of
implementation just don't belong there.
IMHO, as always...
Dan