[R] variations in how long commands take

[Guido Masarotto]

On Tue, Jul 17, 2001 at 01:58:12PM -0400, David Kane  <David Kane wrote:
> > m <- matrix(1, 400, 40000)
> > proc.time(x0 <- apply(m, 2, sum))
> [1] 21.88  3.16 40.13  0.00  0.00
> 
> So far, so good. This is more than twice as fast as the same thing in S+
> 6.0. But when I re-issue this command, I get:
> 
> > proc.time(x0 <- apply(m, 2, sum))
> [1] 37.09  4.65 63.13  0.00  0.00
> > proc.time(x0 <- apply(m, 2, sum))
> [1] 52.34  5.44 85.29  0.00  0.00
> 
> So, my first question is: Why do the times keep going up? I first assumed that

>From help(proc.time)

 `proc.time' determines how much time (in seconds) the currently
  running R process already consumed.

Perhaps, you want to look to the help page of 'system.time'.


guido
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