Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site geowhiz.UUCP Path: utzoo!watmath!clyde!burl!ulysses!gamma!epsilon!zeta!sabre!petrus!bellcore!decvax!genrad!panda!talcott!harvard!seismo!uwvax!geowhiz!karsh From: karsh@geowhiz.UUCP (Bruce Karsh) Newsgroups: net.physics Subject: Re: Quickly Computing Quarks (Science News, VOL. 128) Message-ID: <230@geowhiz.UUCP> Date: Thu, 22-Aug-85 01:00:57 EDT Article-I.D.: geowhiz.230 Posted: Thu Aug 22 01:00:57 1985 Date-Received: Sat, 24-Aug-85 19:16:58 EDT References: <509@sri-arpa.ARPA> Reply-To: karsh@geowhiz.UUCP (Bruce Karsh) Organization: UW Madison, Geology Dept. Lines: 32 In article <509@sri-arpa.ARPA> WBD.TYM@OFFICE-2.ARPA writes: >From: William Daul / McDonnell-Douglas / APD-ASD> >A team of physicists >will soon take over a specially built computer designed to solve a single >physics problem. According to an IBM official, this computer is supposed to >take less than a year to solve a provblem that would take a CRAY-1 >supercomputer more than 300 years to do. >The IBM machine, developed at the Thomas J. Watson Research Center in Yorktown >Heights, N.Y., consists of an array of 576 processors, each one capable of 20 >million "floating point" operations per second (equivalent to multiplying two >decimal numbers 20 million times). In contrast, a typical personal computer >performs 1,000 or so such operations per second. When all the processors are >working in parallel, each one handling a small part of a computation, the IBM >computer can handle more than 10 billion floating point operations per second. Does anybody know how you would go about retaining significant digits in a computation like this? If you figure there there will be about 10**9 round off errors per second accumulating for one year, there must be some plans for designing the calculations to be *EXTREMELY* insensitive to round off problems. How is this going to work? Is there literature on this subject? -- Bruce Karsh U. Wisc. Dept. Geology and Geophysics 1215 W Dayton, Madison, WI 53706 (608) 262-1697 {ihnp4,seismo}!uwvax!geowhiz!karsh