Thread Links Date Links
Thread Prev Thread Next Thread Index Date Prev Date Next Date Index

Re: Fw: Useless sNaNs... or useful?



> Date: Fri, 15 Oct 2010 16:00:46 -0400
> Subject: Re: Fw: Useless sNaNs... or useful?
> From: Lee Winter <lee.j.i.winter@xxxxxxxxx>
> To: Dan Zuras Intervals <intervals08@xxxxxxxxxxxxxx>
> Cc: Ian McIntosh <ianm@xxxxxxxxxx>, stds-1788@xxxxxxxxxxxxxxxxx
> 
> On Fri, Oct 15, 2010 at 3:14 PM, Dan Zuras Intervals
> <intervals08@xxxxxxxxxxxxxx> wrote:
> >> Subject: Fw: Useless sNaNs...  or useful?
> >> . . .
> >>
> >> One important use is to initialize all floating point variables to
> >> signaling NaNs.  If they are inadvertently not properly initialized la=
> >>
> >> . . .
> >>
> >> - Ian McIntosh   IBM Canada Lab  Compiler Back End Supp=
> >>
> >
> > I know of no companies doing this today.
> 
> It is not up to companies.  It is up to software implementors.
> 
> . . .
> 
> >
> > Please name them.
> 
> Lee Winter

	It doesn't matter.

	Just name them.

	If my tone sounds challenging, that is only
	partially true.

	What you & Ian probably don't know is that
	I, along with Prof Kahan & Bob, advocated
	for consistent behaviors for signalling NaNs
	that would permit exactly this application.

	As it happened there were sound technical
	reasons for features that made it infeasible.
	All of which were thought to be more important
	than this application.  All of which I can
	describe for you in detail but hesitate to do
	so in this forum.

	So if there are people out there doing this,
	I want to know who they are.  Others will
	want to know as well.

	Who are they?

			   Dan