[R] System.time

Stavros Macrakis macrakis at alum.mit.edu
Thu Feb 12 15:42:43 CET 2009

On Thu, Feb 12, 2009 at 4:28 AM, Gavin Simpson <gavin.simpson at ucl.ac.uk> wrote:
> When I'm testing the speed of things like this (that are in and of themselves
> very quick) for situations where it may matter, I wrap the function call in a call
> to replicate():
> system.time(replicate(1000, svd(Mean_svd_data)))
> to run it 1000 times, and that allows me to judge how quickly the
> function executes.

I do the same, but with a small twist:

     system.time(replicate(1000, {svd(Mean_svd_data); 0} ))

This allows the values of svd(...) to be garbage collected.

If you don't do this and the output of the timed code is large, you
may allocate large amounts of memory (which may influence your timing
results) or run out of memory (which will also influence your timing
results :-) ),


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