[R] command similar to colSums for rowSums?

[David Winsemius]

On Nov 30, 2009, at 11:10 AM, Will Carr wrote:

>
> Working with an NxMxO sized matrix, currently I can do this in my  
> code:

What are M, N, and O? All the same magnitude?
>
> if (max(colSums(array)) >= number)
>
> But to get an equivalent result using rowSums, I have to do:
>
> for (i in 1:10)
> {
> if (max(rowSums(array[,,i])) >= number)

What are you doing based on that if( ) determination?

> }
>
> I'm running both in a much larger loop that loops millions of times,  
> so
> speed and such is quite a big factor for me. Currently, the colSums  
> line
> uses about 1/10th as much time as the rowSums' for loop, and the for  
> loop
> actually took as much time as the rest of my code combined took to  
> execute.

Are you sure you are interpreting your profile results correctly?

> Is there a faster way than using a for loop and rowSums?

It may depend on what you are trying to do, which at the moment is  
most unclear.

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David Winsemius, MD
Heritage Laboratories
West Hartford, CT