Path: utzoo!utgpu!water!watmath!clyde!bellcore!rutgers!mailrus!utah-gr!utah-cs!cs.utexas.edu!longway!std-unix From: std-unix@longway.TIC.COM (Moderator, John S. Quarterman) Newsgroups: comp.std.unix Subject: Re: Floating Point Verification Message-ID: <214@longway.TIC.COM> Date: 22 Jul 88 17:53:13 GMT References: <208@longway.TIC.COM> Reply-To: Dominic Dunlop Organization: Sphinx Ltd., Maidenhead, England Lines: 71 Approved: jsq@longway.tic.com (Moderator, John S. Quarterman) From: Dominic Dunlop Cc: bryson In article <208@longway.TIC.COM> Derry Bryson writes: >I am searching for a standard to check floating point processors and >emulators against. Basically what I would like to find is a program >that performs several operations and evaluates the accuracy of the answers >based upon some kind of accepted standard. >... >Volume-Number: Volume 14, Number 28 ;login:, Volume 11, Number 2, March/April, 1986, pp 31-56 A Report on the Accuracy of Some Floating Point Math Functions on Selected Computers Technical Report GIT-ICS 85/06 Eugene H Spafford John C Flaspohler School of Information and Computer Science Georgia Institute of Technology Atlanta, Georgia 30332-0280 (404) 894-3152 Software Engineering Research center Georgia Institute of Technology Atlanta, Georgia 30332-0280 (404) 894-3180 Abstract The UNIX operating system and the C programming language have gained a large folloing in recent years, especially in research and academic settings. C and UNIX-like environments are available on a wide variety of machines from personal computer 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 test on more than a dozen different computer systems under various versions of UNIX and UNIX-like environments. Funding for the original printing of this report was obtained from the School of Information and Computer Science, and from the Software Engineering Research Center. Copies of this report may be requested by sending US mail to the authors at the address given on the title page or from {akgua,decvax,hplabs,ihnp4,seismo}!gatech!tech-reports Well, the path's a history lesson, [ Spafford is now at Purdue, and can be reached as spaf@cs.purdue.edu; as Dominic alludes, ihnp4 and seismo are effectively dead, but gatech is still quite active, and can be reached from most of the known world. -mod ] but the paper's well worth getting hold of. It pulls no punches in showing some magnificently awful results. No re-usable test suite is mentioned -- although I dare say Georgia Institute of Technology may still have one. The tests used were carefully coded from ``random accuracy tests for various standard mathematical functions'' given in _Software Manual for Elementary Functions_, William J Cody Jr. & William Waite, Computational Mathematics, Prentice-Hall, 1980. It came as a surprise to me that the 3B2 had the most accurate math package at the time. It was also as slow as hell, but that's been fixed now. Wonder how accurate the new math package is... -- Dominic Dunlop domo@sphinx.co.uk domo@riddle.uucp Volume-Number: Volume 14, Number 33