This is not surprizing at all! The exact result is log(8,2) = 3, but the numerical procedure which calculates the logarithm may produce a result which is a few ULPs different from the exact one, i.e. you can get that log(8,2) = 2.99999999999999 and then floor(2.99999999999999) = 2.
--- Fausto Galli <[EMAIL PROTECTED]> wrote: > > Hello everybody > > My collegue and I noticed a strange behaviour of R > on different > platforms. It's a simple computation, but results > are rather different. > > On Windows XP: > > > floor(log(8,2)) > [1] 3 > > which is what one should expect. > Here's instead the result with Mac OS X (same > version, 2.5.0 > (2007-04-23)) > > > floor(log(8,2)) > [1] 2 > > Is it a "bug" in R or in the operating system? > Anyway, it's quite a surprising one. > > > > > > _____________________________________ > Fausto Galli > Institute of Finance > University of Lugano > Via G. Buffi 13 > CH-6904 Lugano, Switzerland. > +41 (0)58 666 4497 > http://www.people.lu.unisi.ch/gallif > > ______________________________________________ > 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. > ______________________________________________ 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.