On Fri, Sep 18, 2015 at 8:39 AM, John Kane <jrkrid...@inbox.com> wrote:
> It appears that at least three major spreadsheets, Excel, Apache > OpenOffice Cal and gnumeric have a problem with the correct order of > operations when dealing with exponents. The gnumeric result is very strange. > > This problem has probably been reported before but just in case it has > not, it would appear to be one more serious problem with spreadsheets. It > might be useful in warning people away from using a spreadsheet for serious > analysis. > > Excel > > -2^2 = 4 > > 2^2^3 = 64 > > Apache OpenOffice > > -2^2 = 4 > > 2^2^3 = 64 > My opinion: One correct, one error! R agrees with me on this: > 2^2 [1] 4 > 2^2^3 [1] 256 > 2^(2^3) [1] 256 > -2^2 [1] -4 > (-2)^2 [1] 4 > > > gnumeric # note one correct, one error! > My opinion: two correct! > > -2^2 = 4 > > 2^2^3 = 256 > > John Kane > Kingston ON Canada > > Seems to be a bit off-topic. Unless your point to is to use R for important work instead of some spreadsheet. A point with which I completely agree! MS-Excel, and Apache OpenOffice, appear to implement the above as (2^2)^3==64. Whereas gnumeric implements appears to implement this as: 2^(2^3)==256. Which is "correct"? Depends on whom you ask. ref: https://en.wikipedia.org/wiki/Order_of_operations <quote> If exponentiation is indicated by stacked symbols, the usual rule is to work from the top down, thus: [image: a^{b^c} = a^{(b^c)}], which typically is not equal to [image: (a^b)^c]. However, some computer systems may resolve the ambiguous expression differently. For example, Microsoft Office Excel <https://en.wikipedia.org/wiki/Microsoft_Office_Excel> evaluates *a*^*b*^*c* as (*a*^*b*)^*c*, which is opposite of normally accepted convention of top-down order of execution for exponentiation. If a=4, p=3, and q=2, [image: a^{p^q}] is evaluated to 4096 in Microsoft Excel 2013, the same as [image: (a^p)^q]. The expression [image: a^{(p^q)}], on the other hand, results in 262144 using the same program. </quote> Gnumeric abides by the above definition. FWIW. BTW - MS-Excel also has 1900 as a friggin' leap year (due to Lotus 1-2-3 apparently), so I don't consider MS-Excel (or anything else from MS for that matter) to be a definitive source of correctness. Personal opinion. FSF associate member. Penguinista. -- Schrodinger's backup: The condition of any backup is unknown until a restore is attempted. Yoda of Borg, we are. Futile, resistance is, yes. Assimilated, you will be. He's about as useful as a wax frying pan. 10 to the 12th power microphones = 1 Megaphone Maranatha! <>< John McKown [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.