On Thu, Jun 24, 2010 at 12:41 AM, Joris Meys <jorism...@gmail.com> wrote: > Which other Linear Algebra system, and which function did you use in R? > Cheers > Joris
Never mind, off course you used "eigen()"... Eigenvectors are only determined up to a constant. If I'm not mistaken (but check the help files on it), R normalizes the eigenvectors (and so does your other Linear Algebra system). This makes the eigenvectors defined up to the sign. Cheers Joris > > On Thu, Jun 24, 2010 at 12:32 AM, <rkevinbur...@charter.net> wrote: >> Forgive me if I missunderstand a basic Eigensystem but when I present the >> following matrix to most any other LinearAlgebra system: >> >> 1 3 1 >> 1 2 2 >> 1 1 3 >> >> I get an answer like: >> >> //$values >> //[1] 5.000000e+00 1.000000e+00 -5.536207e-16 >> >> //$vectors >> // [,1] [,2] [,3] >> //[1,] 0.5773503 -0.8451543 -0.9428090 >> //[2,] 0.5773503 -0.1690309 0.2357023 >> //[3,] 0.5773503 0.5070926 0.2357023 >> >> But R gives me: >> >> //$values >> //[1] 5.000000e+00 1.000000e+00 -5.536207e-16 >> >> //$vectors >> // [,1] [,2] [,3] >> //[1,] -0.5773503 -0.8451543 -0.9428090 >> //[2,] -0.5773503 -0.1690309 0.2357023 >> //[3,] -0.5773503 0.5070926 0.2357023 >> >> The only difference seems to be the sign on the first eigen vector. What am >> I missing? >> >> Kevin >> >> ______________________________________________ >> 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. >> > > > > -- > Joris Meys > Statistical consultant > > Ghent University > Faculty of Bioscience Engineering > Department of Applied mathematics, biometrics and process control > > tel : +32 9 264 59 87 > joris.m...@ugent.be > ------------------------------- > Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php > -- Joris Meys Statistical consultant Ghent University Faculty of Bioscience Engineering Department of Applied mathematics, biometrics and process control tel : +32 9 264 59 87 joris.m...@ugent.be ------------------------------- Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php ______________________________________________ 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.
