7.31 Why doesn't R think these numbers are equal?
On Fri, 27 Jul 2007, Talbot Katz wrote: > Hi. > > I recently tried the following in R 2.5.1 on Windows XP: > >> ev2<-c(0.8,-0.6) >> ev1<-c(0.6,0.8) >> ev1%*%ev2 > [,1] > [1,] -2.664427e-17 >> sum(ev1*ev2) > [1] 0 >> > > (I got the same result with R 2.4.1 on a different Windows XP machine.) > > I expect this issue is very familiar and probably has been discussed in this > forum before. Can someone please point me to some documentation or > discussion about this? Is there some standard way to get the "correct" > answer from %*%? > > Thanks! > > -- TMK -- > 212-460-5430 home > 917-656-5351 cell > > ______________________________________________ > R-help@stat.math.ethz.ch 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. > Charles C. Berry (858) 534-2098 Dept of Family/Preventive Medicine E mailto:[EMAIL PROTECTED] UC San Diego http://famprevmed.ucsd.edu/faculty/cberry/ La Jolla, San Diego 92093-0901 ______________________________________________ R-help@stat.math.ethz.ch 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.