Zitat von Barry Rowlingson <[EMAIL PROTECTED]>: > Peter Flom wrote: > > I tried your sample code, and a few other variations, and > got 0 for all > > of them, running R 1.8.1 on a Windows machine > > Not only do I get 0 on R 1.8.1 on Unix (linux, RH8), I get > _exactly_ > 0. I thought this was going to be a simple arithmetic > precision problem, > but this test script shows the answers to be exactly zero: > > zertest <- function(q){ > if( q != 0 ){ > theCall <- deparse(substitute(q)) > cat(paste("failed",theCall,' : got ',q,'\n',sep=' ')) > } > } > > # these fail, as expected: > zertest(sd(c(1,2,3))) > zertest(sd(c(rep(0.01,12),0.00000001))) > > # these pass as zero: > zertest(sd(rep(0.01, 13))) #1.805557e-18
This doesnt pass as zero: > zertest(sd(rep(0.01, 13))) failed sd(rep(0.01, 13)) : got 1.80555743920831e-18 I use Unix-Version Sun OS 5.9. I didnt compile it myself. Could compiler/config problems have caused this? > zertest(sd(rep(0.001, 13))) #4.513894e-19 This doesnt pass, either. > zertest(sd(rep(0.00001, 13))) #0 > zertest(sd(rep(0.00000001,13))) #0 > > Might be a compiler/config funny. Andreas: what 'UNIX' is > this? Did > you compile R yourself? Did you run 'make check'? > > Baz > > > ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html