[R] attribute and main value

[Duncan Murdoch]

On 29/12/2014 10:32 AM, Gerrit Draisma wrote:
> Just a curiosity question:
> 
> In the documentation for the nlm procedure
> a find this example of defining a function
> with a gradient attribute:
> -----------
>       f <- function(x, a)
>       {
>           res <- sum((x-a)^2)
>           attr(res, "gradient") <- 2*(x-a)
>           res
>       }
> -----------
> I get the gradient with
>       attr(f(3,2),"gradient")
> but how do I get the function value it self?

value <- f(3,2)
gradient <- attr(value, "gradient")

Duncan Murdoch