[R] finding the values to minimize sum of functions

2012-07-19 Thread Linh Tran
Hi fellow R users, I am desperately hoping there is an easy way to do this in R. Say I have three functions: f(x) = x^2 f(y) = 2y^2 f(z) = 3z^2 constrained such that x+y+z=c (let c=1 for simplicity). I want to find the values of x,y,z that will minimize f(x) + f(y) + f(z). I know I can use

Re: [R] finding the values to minimize sum of functions

2012-07-19 Thread Joshua Wiley
Hi Linh, Here is an approach: f - function(v) { v - v/sum(v) (v[1]^2) + (2 * v[2]^2) + (3*v[3]^2) } (res - optim(c(.6, .3, .1), f)) res$par/sum(res$par) This is a downright lazy way to implement the constraint. The main idea is to combine all three functions into one function that takes

Re: [R] finding the values to minimize sum of functions

2012-07-19 Thread Petr Savicky
On Thu, Jul 19, 2012 at 10:24:17AM -0700, Linh Tran wrote: Hi fellow R users, I am desperately hoping there is an easy way to do this in R. Say I have three functions: f(x) = x^2 f(y) = 2y^2 f(z) = 3z^2 constrained such that x+y+z=c (let c=1 for simplicity). I want to find the