On Thu, Mar 01, 2012 at 04:55:55PM -0500, Sarah Goslee wrote: > Of course there's rounding error: your computer can't > store those decimal numbers precisely. See R FAQ 7.31 for > details. > > See also: > sum(10*c(-0.2, 0.8, 0.8, -3.2, 1.8)) / 10
Hi. This is 0. This works without rounding for one digit precision, since we always have i == 10*(i/10). Already for two digits, we may have i != 100*(i/100). So, for example sum(100*c(0.28, -0.21, 0.66, -0.73))/100 [1] 3.552714e-17 Rounding the multiples to be integers yields the expected result sum(round(100*c(0.28, -0.21, 0.66, -0.73)))/100 [1] 0 Petr Savicky. ______________________________________________ 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.
