[R] System.time

hadley wickham h.wickham at gmail.com
Thu Feb 12 16:10:20 CET 2009

On Thu, Feb 12, 2009 at 8:42 AM, Stavros Macrakis <macrakis at alum.mit.edu> wrote:
> 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} ))

You could also do

r_ply(1000, svd(Mean_svd_data))

which has the same effect - the results are discarded after each
evaluation (as opposed to raply, rlply and rdply where they are kept
and returned in various formats)



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