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.
Robert Farley Metro www.Metro.net -----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" > 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. ______________________________________________ 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.
