%A Eugene Spafford
%A John Flashpohler
%T A Report on the Accuracy of Some Floating Point Math Functions
on Selected Computers
%R Technical Report GIT-ICS-85/06
%I School of Information and Computer Science, Georgia Institute of Technology
%D December 1985
%X The Unix operating system and the C programming language have gained a
large following in recent years, especially in research and academic
settings.  C and Unix-like environments are available on a wide variety
of machines, from personal computers to mainframe computers; however,
few, if any, of these implementations provide accurate floating point
libraries, although users tend to believe they do.  This paper presents
the results of running a set of accuracy tests on more than a dozen
different computer systems under various versions of Unix and Unix-like
environments.
.lp
We believe the results presented in our report should be of major
concern to anyone using floating point library routines in their work
or research, including users of ``packaged'' software like statistics
systems and spreadsheets.  The 14 systems we tested for our report
included Vaxen running 4.2 BSD, a Pyramid 90x, an AT&T 3B20S, an AT&T
7300, a Sun 2, a Ridge, a Cyber and a Masscomp.  To summarize, we found
*no* system with an adequate set of functions.  More than a few of the
systems were 100% inaccurate in some of the tests.