On Thu, 28 Oct 2004, Guan Xing wrote: > I am using lars package written by Dr. Trevor Hastie, the version is > lars_0.9-5 downloaded from cran. When I ran the diabetes example data > attached in package, I found that the beta outputs from different > machines are different. The difference is only about 10^-11 to 10^-12, > some friends suggested that it possibly is a machine precision problem. > But I check the machine numerical characteristics with command " > str(.Machine)", all four machines I am using give me same information. I > am wondering whether someone has noticed this problem before. Could I > make some restriction and get the same results on all machines
Yes. Run exactly the same version of R (that is, the exact same files) on all the machines, if they have exactly the same OS and similar chips. Otherwise you and your friends need to take a course in numerical methods. Even different versions of the same compiler will produce different code ordering operations differently and some give different results. For example, R built with --enable-R-shlib gives different answers to that built without, and R using different BLAS libraries can give quite different answers. -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
