Paper Info
Title
On Fast and Exact Computation of Error Metrics in Approximate LSB Adders
Abstract
In recent years, several approximate adders have been proposed which are targeted for energy-efficient system design specific to error-tolerant applications. An approximate least significant bit (LSB) adder (ALA) is one such class of adder which is composed of two adder segments: one accurate most significant adder segment and one LSB adder segment approximated with inexact adder components. Error metrics such as mean error distance (MED), mean square error distance (MSED), and worst case error (WCE) have been used widely in existing studies to characterize and compare various approximate adders. In this article, we propose three independent algorithms to compute exact values of MED, MSED, and WCE, respectively, for an ALA. The algorithms are based on an iterative computation of intermediate parameters from least significant sub-adder block to the most significant sub-adder block constituting the ALA. The simulation results show that for 16-bit ALAs, the proposed MED and MSED computation algorithms are, respectively, about <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.4\times 10^{3}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.6\times 10^{3}$ </tex-math></inline-formula> times faster than Monte Carlo (MC) simulation with 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">16</sup> samples. Similarly, WCE computation method is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10.4\times 10^{3}$ </tex-math></inline-formula> times faster compared to the MC simulation with 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">16</sup> samples.
Year
DOI
Venue
2020
10.1109/TVLSI.2020.2967149
IEEE Transactions on Very Large Scale Integration (VLSI) Systems
Keywords
DocType
Volume
Approximate adders,approximate computing,error metric computation,mean error distance (MED),worst case error (WCE)
Journal
28
Issue
ISSN
Citations 
4
1063-8210
0
PageRank 
References 
Authors
0.34
0
3
Name
Order
Citations
PageRank
Avishek Sinha Roy101.35
Rajdeep Biswas200.34
Anindya Sundar Dhar39726.09