Hi Robin, This works! Also your introduction to using S4 methods is very good!
Thanks! Feng On Wed, Feb 11, 2009 at 12:20 PM, Robin Hankin <rk...@cam.ac.uk> wrote: > Feng > > checkout the Brobdingnag package: > > > > library(Brobdingnag) > > exp(1000)/(exp(1007)+5) > [1] NaN > > > as.numeric(exp(as.brob(1000))/(exp(as.brob(1007))+5)) > [1] 0.000911882 > > > > Feng Li wrote: > >> Dear R, >> >> I have two questions: >> >> 1, Why both R and Matlab give 0*Inf==NaN? To my knowledge, it should be >> zero >> mathematically. Am I right? >> >> 2, I need to calculate e.g. exp(a)/(exp(b)+c), where both a and b are very >> large numbers (>>1000, e.g a=1000, b=1007, and c=5). R gives me NaN when I >> use the following command: >> >> >> >>> exp(1000)/(exp(1007)+5) >>> >>> >> [1] NaN >> >> I am pretty sure this should be close to zero. My question is whether >> there >> is a general way to solve this kind of question or should I do some >> settings >> before computing? >> >> >> Thanks in advance! >> >> >> Feng >> >> >> >> >> > > > -- > Robin K. S. Hankin > Uncertainty Analyst > University of Cambridge > 19 Silver Street > Cambridge CB3 9EP > 01223-764877 > > -- Feng Li Department of Statistics Stockholm University 106 91 Stockholm, Sweden [[alternative HTML version deleted]] ______________________________________________ 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.