Article View: comp.lang.fortran
Article #6516Re: Precision of floating point multiply
From: Tim Prince
Date: Sat, 27 Sep 2003 03:17
Date: Sat, 27 Sep 2003 03:17
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2493 bytes
Glen Herrmannsfeldt wrote: > As far as I know, Fortran still requires floating point multiply to > generate a result with no more precision than the arguments that went into > it. W.Kahan describes well the advantage of summing a double precision > product of single precision arguments, yet the Fortran standard doesn't > seem to > follow it. (Someone with a more recent standard can comment on this.) > I doubt that all the machines we've been using violate the Fortran standard. Didn't f77 introduce DPROD() specifically to require a double precision product, in case that should be required? > If someone wanted to comment about other hardware or compilers in use in > the 1960's and 1970's, that might also be useful. > > The GE600/Honeywell6000, and probably the Univac 36-bit machines, generated an 80-bit product. -- Tim Prince
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X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: fd4af,7830916812112af0 X-Google-Attributes: gidfd4af,public X-Google-Thread: fd705,7830916812112af0 X-Google-Attributes: gidfd705,public X-Google-Thread: 102b75,7830916812112af0 X-Google-Attributes: gid102b75,public X-Google-Thread: 1094ba,7830916812112af0 X-Google-Attributes: gid1094ba,public X-Google-ArrivalTime: 2003-09-26 20:18:02 PST Path: arc1-ca.pugleaf.net!news1.google.com!newsfeed.stanford.edu!logbridge.uoregon.edu!prodigy.com!newsmst01.news.prodigy.com!prodigy.com!postmaster.news.prodigy.com!newssvr13.news.prodigy.com.POSTED!d58ee217!not-for-mail From: Tim Prince <timothyprince@xxxxsbcglobal.net> Subject: Re: Precision of floating point multiply Newsgroups: comp.lang.fortran,comp.arch,bit.listserv.ibm-main,alt.folklore.computers Followup-To: comp.lang.fortran Reply-To: tprince@remove_this_computer.org References: <dG4db.598668$uu5.97984@sccrnsc04> Lines: 21 User-Agent: KNode/0.6.1 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7Bit Message-ID: <Oi7db.199$MR5.25417891@newssvr13.news.prodigy.com> NNTP-Posting-Host: 67.112.24.240 X-Complaints-To: abuse@prodigy.net X-Trace: newssvr13.news.prodigy.com 1064632622 ST000 67.112.24.240 (Fri, 26 Sep 2003 23:17:02 EDT) NNTP-Posting-Date: Fri, 26 Sep 2003 23:17:02 EDT Organization: SBC http://yahoo.sbc.com X-UserInfo1: FKPO@SVG\JUMB\HXWBO@^RLAVB]FBL@MAHU^_BAMEH]TCDYG^WHKAH_[JTXDX_KI\VB]JBVMS^YT_G[CZVWAOS\DHFWEH]@KGXYHB\_CMDSFABP^J[AHHRKARLE_JDBLJ\XA[JRMEI]MGJSPB\Y]^KG\@S^@VQKI_Q[G@@_ACSARASDEFLBJ]S\GFNTUAVBL Date: Sat, 27 Sep 2003 03:17:02 GMT