Update on Unums

[H. S. Teoh via Digitalmars-d-announce]

On Tue, Mar 14, 2017 at 06:50:07PM +0000, Nick B via Digitalmars-d-announce wrote:
> On Tuesday, 14 March 2017 at 13:38:09 UTC, jmh530 wrote:
> > On Tuesday, 14 March 2017 at 08:21:03 UTC, Andrea Fontana wrote:
> > > 
> > > It seems public: http://insidehpc.com/2017/02/john-gustafson-presents-beyond-floating-point-next-generation-computer-arithmetic/
> > 
> > Also in pdf here
> > http://web.stanford.edu/class/ee380/Abstracts/170201-slides.pdf
> 
> Thank you both for posting these links :).
[...]

Indeed.

But while the .pdf mentions Posits and Valids, the following slides only
discuss Posits.  Where's the discussion on Valids?

In spite of that, though, Posits appear to be a much better candidate at
replacing IEEE 794 floats than the previous unum incarnations. I felt
the previous incarnations, while clever and workable in theory, posed
too many practical challenges to implement on silicon.  The current
description of Posits seem to be much more feasible to put on silicon.

Still, though, I wonder what Gustafson has up his sleeves wrt. Valids.

But I'm wondering how people would react to switching their numerical
code to projective reals as opposed to the present IEEE 794 system where
you can distinguish between +inf and -inf.  Projective reals have
nice(r) closure properties, but I can see some cases where being unable
to distinguish between +inf and -inf may be problematic.


T

-- 
When solving a problem, take care that you do not become part of the problem.