>
> Oh! because I would like to plot an implicit function R(x,y) = 0,
>
> addplot3 seems to plot the threedimensional visualization.
>
>
I don't think either tikz or gnuplot support such functional plot.
Yes, addplot3 is a 3D visualization, given x,y.
Hmmm, I am not a friend to implicit function. But my thinking (maybe totally wrong) is displayed below.
since y is supposed to be a function of x, i.e., y=f(x), is it possible to use derivative technique to find analytic function of x, then plot f(x) using addplot. If singularity is/are encountered, just avoid plotting it/them.
If not applicable, here is a website for related problem. Hoping it will help.
http://pbelmans.wordpress.com/2010/11/11/howto-draw-algebraic-curves-using-pgftikz/
Good luck