Thank you so much, Michael and Duncan. It worked. Annie
On Thu, Aug 11, 2011 at 2:23 PM, Duncan Murdoch <murdoch.dun...@gmail.com>wrote: > On 11/08/2011 3:11 PM, annie Zhang wrote: > >> Hi All, >> >> I have a 2-dim density defined on 0<x<1, 0<y<1, x<y. I know the exact >> formula of the density. How can I visualize it? What plot functions can I >> use? >> > > > persp() or contour() are in the graphics package. There are similar ones > in lattice (and I think in ggplot2), but I forget their names. There's also > persp3d() in the rgl package for a rotatable version of persp(). > > Supposing f(x,y) gives the density at (x,y) (or NA if x > y), you plot it > as follows: > > x <- seq(0, 1, len=30) > y <- seq(0, 1, len=30) > z <- outer(x, y, f) > persp(x,y,z) > contour(x,y,z) > persp3d(x,y,z) > > This relies on f() being vectorized; if it's not, use > > z <- outer(x,y, Vectorize(f)) > > instead. > > Duncan Murdoch > [[alternative HTML version deleted]] ______________________________________________ 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.