Try with predict: plot(x, y) lines(0:10, predict(yfit, list(x = 0:10)))
2009/10/9 Primoz PETERLIN <primozz.peter...@gmail.com>: > Dear all, > > Here I come with another stupid question. Suppose I want to use nls() > to fit a series of data (here modelled by generated points), then plot > the points and the fitting curve. I figured out some way of doing it: > > x <- runif(1:20, 0, 10) > y <- 0.1*x^2 - rep(3, length(x)) + rnorm(length(x), sd = 0.5) > > yfit <- nls(y ~ a*x^2 + b*x + c, > start = list(a = 1, b = 1, c = 1), > trace = TRUE) > > plot(x, y) > curve(coef(yfit)[1]*x^2 + coef(yfit)[2]*x + coef(yfit)[3], 0, 10, > add = TRUE) > > However, this code is rather fortranesque, and most likely there > exists a much more elegant way in R/S, something like abline() which > exists for straight lines. Since both the formula and the coefficients > are available as a result of nls() (here as formula(yfit) and > coef(yfit)), I thought there ought to be a way something along the > following lines: > > f <- substitute(formula(yfit), as.list(coef(yfit))) > curve(f, ...) > > However, this snippet of code doesn't work. Am I thinking into the > correct direction at all? > > Thanks in advance. > > All the best, > Primož > > -- > Primož Peterlin, Inštitut za biofiziko, Med. fakulteta, Univerza v Ljubljani > Lipičeva 2, SI-1000 Ljubljana, Slovenija. primoz.peter...@mf.uni-lj.si > Tel +386-1-5437612, fax +386-1-4315127, http://biofiz.mf.uni-lj.si/~peterlin/ > F8021D69 OpenPGP fingerprint: CB 6F F1 EE D9 67 E0 2F 0B 59 AF 0D 79 56 19 0F > > ______________________________________________ > 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. > -- Henrique Dallazuanna Curitiba-Paraná-Brasil 25° 25' 40" S 49° 16' 22" O ______________________________________________ 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.
