# [R] Matrices in R - Simple question?

David Winsemius dwinsemius at comcast.net
Wed Mar 11 03:01:56 CET 2009

```I suspect you probably need to provide an example that illustrates why
this seems difficult:

> x <- 1:10
> f1 <- function(x) exp(x)
> g1 <- function (x) log(x)
> h1 <- function (x) x^(1/2)
# any of these functions would return a 10 element vector if given x
as an argument

> f1(x)*g1(x)*h1(x)
[1] 0.000000e+00 7.243182e+00 3.821981e+01 1.513782e+02 5.341111e+02
1.770607e+03 5.645900e+03 1.753265e+04 5.341289e+04
[10] 1.603838e+05

> sum( f1(x)*g1(x)*h1(x) )
[1] 239476.8

Examples might help ....
--
David Winsemius

On Mar 10, 2009, at 7:38 PM, Lars Bishop wrote:

> Hi,
>
> I'm a new R user and would appreciate your help regarding the
> following: Can
> I create a matrix whose elements are n functions of a vector x? In my
> problem I have 3 vectors (a,b,c) with elements a=[f1(x)
> f2(x)....fn(x)];
> b=[g1(x) g2(x)....gn(x)]; c=[h1(x) h2(x)....hn(x)].

> I need to create a final
> function that looks like: f(x)=f1(x)*g1(x)*h1(x)+.....
> +fn(x)*gn(x)*hn(x).
> (f(x) is my objective function of an optimization problem).Is this
> possible
> to create f(x) in the way I described?
>
>
>
> Lars.
>
> 	[[alternative HTML version deleted]]
>
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