RIKEN Center for Computational Science


The 181st R-CCS Cafe -partⅡ

The 181st R-CCS Cafe -part Ⅱ
Date and Time: Tue. Sep. 17, 2019, 16:10 - 16:50
Place: Lecture Hall (6th floor) at R-CCS

Title: Using Field-Programmable Gate Arrays to Explore Different Numerical Representation: A Use-Case on POSITs
Speaker: Artur Podobas (Processor Research Team)

Presentation Language: English
Presentation Material: English


The inevitable end of Moore’s law motivates researchers to re-think many of the historical architectural decisions. Among these decisions we find the representation of floating-point numbers, which has remained unchanged for nearly three decades. Chasing better performance, lower power consumption or improved accuracy, researches today are actively searching for smaller and/or better representations. Today, a multitude of different representations are found in the specialized (e.g. Deep-Learning) applications as well as for general-purpose applications (e.g. POSITs).
However, despite their claimed strengths, alternative representations remain difficult to evaluate empirically. There are software approaches and emulation libraries available, but their sluggishness only allows the smallest of inputs to be evaluated and understood.
POSIT is a new numerical representation, introduced by professor John Gustafson in 2017 as a candidate to replace the traditional IEEE-754 representation. In this talk I will present my experience in designing, building and accelerating the POSIT numerical representation on Field-Programmable Gate Arrays (FPGAs). I will start by briefly introducing the POSIT representation, show its hardware implementation details, reasoning around their trade-offs (with respect to IEEE-754) and conclude the presentation with small use-cases and their measured/obtained performance.