From help-octave-request at bevo dot che dot wisc dot edu Fri Aug 1 08:09:35 2003 Subject: Re: Another newbie question From: WJ Atsma To: "Fausto Arinos de A. Barbuto" Cc: Octave Help List Date: Fri, 1 Aug 2003 10:44:31 +0200 Ola Number of decimal places and precision are not necessarily related, at least not on a computer. The relationship you learn in math and physics (round off to the number of significant digits + 1) is of no concern to the computer. Matlab and excel have the same limitation. The programmer's choice to show zeros rather than the imprecise results from round-off errors after an operation may be nice for the intuitive user, but don't really provide information. For example, 1.000000 +/- 0.2 is just as accurate as 1.00233748 +/- 0.2. The round-off provides useful information sometimes even. Not to say that something useful couldn't be done. It should be possible to pass numbers with a precision qualifier and propagate it through your equations, but nobody has done this and I don't know of any other numerical packages/spreadsheets that do. Happy computing, Willem On 2003.08.01 02:02 Fausto Arinos de A. Barbuto wrote: > > On Thu, 2003-07-31 at 10:58, John W. Eaton wrote: > > > | Take Excel as an example. One can increase > > | the floating point representation of any real number by as many > > | decimal places as he/she wants. However, only zeroes are shown > > | from the 14th decimal place on. It also marvels me that a much- > > | less-than-professional program such as Windows Calculator can > > | represent real numbers with 31 exact decimal places -- and Octave > > | can't. > > > > If you are trolling, find another venue. If you have a real ------------------------------------------------------------- Octave is freely available under the terms of the GNU GPL. Octave's home on the web: http://www.octave.org How to fund new projects: http://www.octave.org/funding.html Subscription information: http://www.octave.org/archive.html -------------------------------------------------------------