Towards a Better Computer Arithmetic:

A unum (Universal Number) Workshop

Monday/Tuesday, October 24-25, 2016


A big issue facing cutting-edge computing is power consumption. A separate plethora of issues also arises when inexact arithmetic is introduced into algorithms. A new arithmetic formulation, involving unums (universal numbers) and SORNs (Sets of Real Numbers), has been proposed as an alternative to traditional floating point. A unum not only contains information about its own accuracy, but also then has the potential to reduce the number of bits required to achieve a required accuracy, thereby addressing each of the above issues. The unum approach is in its infancy; it is both a new format and a new computing environment, and methods of problem solving require reconsideration when using unums. The workshop here then is aimed at educating interested parties on the concept, discussing the pros and cons, elucidating applications, and considering the way foward for practical implementation.

This small workshop is mostly a preliminary community building effort.  We are very interested in meeting anyone in any community that might find the use of unums interesting.  For example, people as diverse as mathematicians that are interested in numerical stability and computer scientists who are concerned with power reduction might find this topic useful.  We are happy to consider other speakers in this workshop, and encourage you to talk to us if you consider yourself a potential speaker.  We are looking for other audience niches to invite too, so please let us know of anyone that might wish to be involved.   Email:  brummell at soe dot ucsc dot edu.

To register for the workshop, and further information on  the CROSS initiative supporting this work, go to:


workshop agenda

10:30am-11:30pm John Gustafson (University of Singapore):  "Unum systems for better computational arithmetic"

11:30pm-12:00pm General discussion of unums

12:00pm-1:30pm Lunch

1:30pm-2:15pm Andrew Shewmaker (LANL): "Measurements For A Tailored Number System"

2:15pm-3:00pm Isaac Yonemoto (  "Unum implementation in Julia"


3:00pm-3:30pm Break

3:30pm-4:15pm Scott Lloyd (LLNL): "LULESH execution with Unums in C/C++"

4:15pm-5:00pm Andrew Klofas (UCSC):  "Progress report of the CROSS Unum project"