[R] Efficient nested loops

[David Winsemius]

On Oct 21, 2010, at 4:40 AM, Francisco Javier Santos Alamillos wrote:

> Dear R community,
>
> I am working with huge arrays, so I spend a lot of time computing.  
> This is
> my code:
>
> for (x in 1:dim(variable)[1]){
>    for (y in 1:dim(variable)[2]){
>        for (z in 1:dim(variable)[3]){
>            result <- max(variable[x,y,z,])
>        }
>    }
> }
>
> Is there a more efficient procedure to do this task?

Are you sure this is a proper specification of the "task"?. You have  
overwritten the "result" with max(.) multiple times (the product of  
the dimensions) and only have at the end that effort just the max of  
the last slice of the variable.

>
> Thanks in advance!
-- 

David Winsemius, MD
West Hartford, CT