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From: s...@gatech.CSNET (Gene Spafford)
Newsgroups: net.research,net.math,net.unix-wizards,net.bugs
Subject: Technical Report of Possible Interest
Message-ID: <2389@gatech.CSNET>
Date: Wed, 8-Jan-86 16:45:54 EST
Article-I.D.: gatech.2389
Posted: Wed Jan  8 16:45:54 1986
Date-Received: Thu, 9-Jan-86 03:28:23 EST
Organization: The Clouds Project, School of ICS, Georgia Tech
Lines: 54

Now available:

"A Report on the Accuracy of Some Floating Point Math Functions
 on Selected Computers," Technical Report GIT-ICS-85/06, 
 by Eugene Spafford and John Flaspohler, Georgia Tech

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

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.

To obtain a copy of this or of any Georgia Tech ICS technical
report, send a surface mail address and the name(s) of the report(s)
you would like.  If possible, please try to include the technical
report number(s) and author name(s).  Send your request via e-mail to:

CSNet:	Tech-Reports @ GATech
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uucp:	...!{akgua,decvax,hplabs,ihnp4,linus,seismo}!gatech!tech-reports

or (preferably) by surface mail to:
	Ms. Karen Hutcheson
	Technical Reports
	School of Information and Computer Science
	Georgia Institute of Technology
	Atlanta, GA 30332-0280

There is no charge for single copies of technical reports still in
their first printings.  Requests received after these editions have
been exhausted, or requests for multiple copies, may be filled after
payment of a small copying fee; details will be mailed back if such a
fee is to be assessed.
Gene "the end is in sight" Spafford
The Clouds Project, School of ICS, Georgia Tech, Atlanta GA 30332-0280
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