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Re: YES P1788/M0029.02:Level3-InterfaceOnly, *BUT*

Lee, Michel,
FYI: You guys might find Siegfried's recent paper on this topic interesting. If you haven't done so already, I recommend reading it. His idea is very interesting. 

Nate
P.S. He made the post Dec. 5, 2011. If you go to the P1788 archives you can find the e-mail and download the PDF.
----- Original Message ----- From: "Michel Hack" <hack@xxxxxxxxxxxxxx> 
To: "stds-1788" <stds-1788@xxxxxxxxxxxxxxxxx>
Sent: Thursday, December 29, 2011 5:00 PM
Subject: YES P1788/M0029.02:Level3-InterfaceOnly, *BUT*



Lee Winter wrote:

I believe the exclusion of overflows of the same sign is unnecessary
for the interchange format.


I suppose you mean two infinities of the same sign.  Infinities may
indeed be the result of containing overflow, but they can also simply
mean "unbounded".  Decorations should tell these cases apart.  (In 754
it is the overflow flag that does the job -- unfortunately globally.)


Exemplar:  Given M = F.max for some 754 format F, then given lo=0.8*M
and hi=0.9*M the interval I_one=[lo hi] is a valid value.  But the
interval I_two = 2 * I_one is not a valid interchange value.


No problem:
I_two would simply be [F.max, +Inf] -- overflow has to observe containment. 

Michel.
---Sent: 2011-12-29 23:06:50 UTC