Dear Rolf, I tryed to follow your advices but the results I am getting seems still strange to me. See below an example of a matrix:
datamat <- matrix(c(2.2, 0.4, 0.4, 2.8), 2, 2) plot(ellipse(datamat),type='l') eigenval <- eigen(datamat)$values eigenvect <- eigen(datamat)$vectors eigenscl <- eigenvect * sqrt(eigenval) * (qchisq(0.95,2))# One solution to get rescale v1 <- (eigenvect[,1])*(sqrt(eigenval[1]))*(qchisq(0.95,2))#or directly rescale the vectors needed v2 <- (eigenvect[,2])*(sqrt(eigenval[2]))*(qchisq(0.95,2)) #Or v1 <- eigenscl[1,] v2 <- eigenscl[2,] segments(-v1[1],-v1[2],v1[1],v1[2]) segments(-v2[1],-v2[2],v2[1],v2[2]) The vectors don't seem to be scaled properly and I don't see what I am doing wrong. Any ideas? Thanks! Antoine -- View this message in context: http://r.789695.n4.nabble.com/Adding-axis-to-an-ellipse-ellipse-package-tp3847954p3862491.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
