[R] How to define specially nested functions

[Petr Savicky]

On Thu, Apr 28, 2011 at 11:08:23PM -0400, Chee Chen wrote:
> Dear All,
> I would like to define a function: f(x,y,z) with three arguments x,y,z, such that: given values for x,y,  f(x,y,z) is still a function of z and that I am still allowed to find the root in terms of z when x,y are given.
> For example: f(x,y,z) =  x+y + (x^2-z),  given x=1,y=3, f(1,3,z)= 1+3+1-z is a function of z, and then I can use R to find the root z=5.

If solving the equation for z with given x and y is the
main purpose, then try the following

  f <- function(x,y,z) x+y + (x^2-z)
  uniroot(f, c(0, 10), x=1, y=3)$root
  [1] 5

Hope this helps.

Petr Savicky.