On Feb 1, 2008 2:46 PM, Martin Maechler <[EMAIL PROTECTED]> wrote: > >> Take this code: > >> > >> > f <- function(x) exp(-x)*x-0.05 > >> > g <- function(x) 0 > >> > curve(f,0,5) > >> > curve(g,add=T) > >> Error in xy.coords(x, y) : 'x' and 'y' lengths differ > >> > > >> > >> However, with > >> > >> g <- function(x) x-x > >> > >> no error is generated. > >> > >> > > BB> The first paragraph of "details" in the help page > BB> says: > > BB> . 'x(t)' or 'expr' (with 'x' inside) must return a numeric of the same > BB> length as the argument 't' or 'x'. > > yes, thanks Ben. > > BB> So no, technically this is not a bug. > > why only "technically"? > > Paul wouldn't also be able to integrate(g, .), just > the error message would be slightly more helpful : > > Error in integrate(g, 0, 1) : > evaluation of function gave a result of wrong length > > > > BB> The R idiom for adding a horizontal line to the plot is > BB> abline(h=...) > > BB> cheers > BB> Ben Bolker
Thanks to all for the clarification. Paul ______________________________________________ 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.