Thread overview
Update on Unums
Mar 13
Nick B
Mar 14
jmh530
Mar 14
Nick B
Mar 14
Nick B
March 13
Hi Everyone

Here is an update on Unums.

John L Gustafson at the Multicore World 2017 Conference, in Wellington,  New Zealand, in February 2017, gave another presentation to his Unum idea.   He has again reworked the basis of his idea again.  He has now called this latest version: Type 3 Unums (2017), and introduced new labels of Posits and Valids for contrasting Calculation Esthetics.

If I get the approval to post Johns latest presentation, I will do so.

cheers
Nick
March 13
On 13/03/2017 9:32 PM, Nick B wrote:
> Hi Everyone
>
> Here is an update on Unums.
>
> John L Gustafson at the Multicore World 2017 Conference, in Wellington,
> New Zealand, in February 2017, gave another presentation to his Unum
> idea.   He has again reworked the basis of his idea again.  He has now
> called this latest version: Type 3 Unums (2017), and introduced new
> labels of Posits and Valids for contrasting Calculation Esthetics.
>
> If I get the approval to post Johns latest presentation, I will do so.
>
> cheers
> Nick

Nice!
March 13
On Mon, Mar 13, 2017 at 08:32:04AM +0000, Nick B via Digitalmars-d-announce wrote:
> Hi Everyone
> 
> Here is an update on Unums.
> 
> John L Gustafson at the Multicore World 2017 Conference, in Wellington,  New Zealand, in February 2017, gave another presentation to his Unum idea.   He has again reworked the basis of his idea again. He has now called this latest version: Type 3 Unums (2017), and introduced new labels of Posits and Valids for contrasting Calculation Esthetics.
> 
> If I get the approval to post Johns latest presentation, I will do so.
[...]

Link?


T

-- 
MSDOS = MicroSoft's Denial Of Service
March 13
On Monday, 13 March 2017 at 15:08:56 UTC, H. S. Teoh wrote:
> On Mon, Mar 13, 2017 at 08:32:04AM +0000, Nick B via Digitalmars-d-announce wrote:
>> If I get the approval to post Johns latest presentation, I will do so.
> [...]
>
> Link?

urmm...


March 14
On Monday, 13 March 2017 at 08:32:04 UTC, Nick B wrote:
> Hi Everyone
>
> Here is an update on Unums.
>
> John L Gustafson at the Multicore World 2017 Conference, in Wellington,  New Zealand, in February 2017, gave another presentation to his Unum idea.   He has again reworked the basis of his idea again.  He has now called this latest version: Type 3 Unums (2017), and introduced new labels of Posits and Valids for contrasting Calculation Esthetics.
>
> If I get the approval to post Johns latest presentation, I will do so.
>
> cheers
> Nick

It seems public: http://insidehpc.com/2017/02/john-gustafson-presents-beyond-floating-point-next-generation-computer-arithmetic/
March 14
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
March 14
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 :).

Cheers
Nick
March 14
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.
March 14
On Tuesday, 14 March 2017 at 19:32:57 UTC, H. S. Teoh wrote:
> 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.

In the Stanford presentation pdf, (note that these change from presentation to presentation) on page 12, is the only mention of Valids. I thought these were a rename of Sets of Real Numbers(SORNS) from his Type 2 Unums, but after reviewing the slides again, I'm not sure.  I believe that this needs to be vertified with Dr Gustafson, as you correctly point out there are no examples of Valids.

But when I review his slides from his New Zealand talk, there is an additional slide, where he states that (1) "Posit pairs beat intervals at their own games, too: Valid mode." and (2) "Posit mode: Round unum after every operation.  Valid mode: rigorous answer bounds; NaN answers are sets. "

If anyone wants a copy of these New Zealand slides, please advise me of your email address.