
From:  WJ Atsma 
Subject:  Re: Another newbie question 
Date:  Fri, 1 Aug 2003 10:44:31 +0200 
OlaNumber 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 roundoff 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 roundoff 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, 20030731 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 >  lessthanprofessional 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 
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