Yes, I see the problem now! Thank you for bearing with me and for the helpful explanations and info.
Best regards, David. 2009/6/20 Stavros Macrakis <macra...@alum.mit.edu>: > On Sat, Jun 20, 2009 at 4:10 PM, Dr. D. P. Kreil <dpkr...@gmail.com> wrote: >> >> Ah, that's probably where I went wrong. I thought R would take the >> "0.1", the "0.3", the "3", convert them to extended precision binary >> representations, do its calculations, an the reduction to normal >> double precision binary floats would only happen when the result was >> stored or printed. > > This proposal is problematic in many ways. For example, it would *still* > not guarantee that 0.3 - 3*0.1 == 0, since extended-precision floats have > the same characteristics as normal-precision floats. Would you round to > normal precision when passing arguments? Then sqrt could not produce > extended-precision results. etc. etc. > > I suppose R could support an extended-precision floating-point type, but > that would require that the *user* choose which operations were in > extended-precision and which in normal precision. (And of course it would be > a lot of work to add in a complete and consistent way.) > > -s > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
