Path: g2news2.google.com!news4.google.com!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail From: nos...@see.signature (Richard Maine) Newsgroups: comp.lang.fortran Subject: Re: how to declare doubles in f95 Date: Wed, 28 Jan 2009 21:27:31 -0800 Lines: 32 Message-ID: <1iu9ut8.eu0q92m2gmncN%nospam@see.signature> References: <0b898c8f-5866-4942-bf2b-171655d6658a@r15g2000prh.googlegroups.com> <1iu9kv0.1bz1pn5whvfi8N%nospam@see.signature> <1nw9yyz9qhd9p.1hjp1zbzhjv22$.dlg@40tude.net> X-Trace: individual.net kEM0owf+eYZo9xobrYyA4QVBH/Q6IHadhd4b7rFfYsnf1+LvTK X-Orig-Path: nospam Cancel-Lock: sha1:Eo577SmpdzrP1MWOq5rLRO+7CRs= User-Agent: MacSOUP/2.8.2 (Mac OS X version 10.5.5 (x86)) Larry Gates wrote: > Aren't implementations required to have both a single and double precision? Yes. Indeed, that seemed rather implicit in all the preceeding posts, which mentioned how to declare double precision without any caveats about whether or not it existed. However I fail to see the relevance of this to anything prior in the thread. I suppose I could make some guesses as to what you think the relevance is, but none of the guesses I can come up with seem particularly good. Most of the guesses I might try are answered by what I already said, so rather than repeat it, I'll mostly just refer back to it. I'll try a bit more long-winded version of the reply to one of the guesses. Note in particular, that although implementations are required to have both single and double precision, there are almost no requirements on what precisions those must be. The only such requirement is that double precision must have more precision than single. It doesn't have to be twice as much (double has to use twice as much storage in storage association contexts, but that doesn't constitute a requirement related to precision - indeed counterexamples exist). Neither single nor double have to have any particular precision that you might have in mind. Nor do they have to have any particular relationship to the precisions natively supported by the hardware in question; practical considerations often come into play in that regard, but the Fortran standard doesn't. -- Richard Maine | Good judgment comes from experience; email: last name at domain . net | experience comes from bad judgment. domain: summertriangle | -- Mark Twain