On Wed, Sep 24, 2008 at 4:14 PM, Farley, Robert <[EMAIL PROTECTED]> wrote: > You could always try > F(x,y) = f(x) + 0*y > > That is "zero out" the degenerate dimensions. Of course you'll be > plotting what is essentially a two dimensional object as if it were > three dimensional. The degeneracy in y means a 2-D curve will be > "extruded" along the Y dimension. > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > On Behalf Of Paul Smith > Sent: Wednesday, September 24, 2008 06:20 > To: [EMAIL PROTECTED] > Subject: Re: [R] How to draw the graph of f(x,y) = x * y ? > > On Wed, Sep 24, 2008 at 4:05 AM, Ben Bolker <[EMAIL PROTECTED]> wrote: >>> The function curve() draws the graph of functions from R to R. Is >>> there some homologous function to curve() to draw functions from R^2 >>> to R? >> >> There is a curve3d function in the emdbook package on CRAN. > > Thanks, Ben and Robin. I think curve3d should be included in the base > of R. It would help many users, I believe. > > I do not know whether curve3d could be extended to draw constant > functions and functions like f(x,y) = x. With the current version, I > get the following: > >> curve3d(1) > Error in curve3d(1) : > 'expr' must be a function or an expression containing 'x' and 'y' >> curve3d(x) > Error in eval(expr, envir, enclos) : could not find function "x" >>
Thanks, Robert. your suggestion works to plot f(x,y) = x + 0*y, but it does not work in the case of f(x,y) = 1 + 0*x +0*y. 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.
