[R] exponentiate elements of a whole matrix

[Barry Rowlingson]

On Wed, Oct 13, 2010 at 11:51 AM, Maas James Dr (MED) <J.Maas at uea.ac.uk> wrote:
> I've tried hard to find a way to exponentiate each element of a whole matrix such that if I start with A
>
> A = [ 2   3
>      2   4]
>
> I can get back B
>
> B = [ 7.38   20.08
>      7.38   54.60]
>
> I've tried
>
> B <- exp(A) but no luck.

 Your matrix notation looks unlike R. We prefer cut n paste examples
here. In which case:

 > A=matrix(1:4,2,2)
 > A
     [,1] [,2]
[1,]    1    3
[2,]    2    4
 > exp(A)
         [,1]     [,2]
[1,] 2.718282 20.08554
[2,] 7.389056 54.59815
 > B=exp(A)
 > B
         [,1]     [,2]
[1,] 2.718282 20.08554
[2,] 7.389056 54.59815

so, works for me (as I expected it would).

 Either you've redefined the exp function or you've accidentally
started matlab instead.

Barry