[R] Computing sums of the columns of an array

Huntsinger, Reid reid_huntsinger at merck.com
Fri Aug 5 18:23:14 CEST 2005


colSums() is a lot faster. 

Reid Huntsinger

-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Martin C. Martin
Sent: Friday, August 05, 2005 12:17 PM
To: r-help at stat.math.ethz.ch
Subject: [R] Computing sums of the columns of an array


Hi,

I have a 5x731 array A, and I want to compute the sums of the columns.  
Currently I do:

apply(A, 2, sum)

But it turns out, this is slow: 70% of my CPU time is spent here, even 
though there are many complicated steps in my computation.

Is there a faster way?

Thanks,
Martin

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