R help - Feb 2009 - System.time

Hi folks!
Does anyone know why I might see something like this after running
system.time?

system.time(svd(Mean_svd_data))
   user  system elapsed
      0       0       0

The data set is tiny and the function returns results instantly, but
shouldn't it still give me a time?

Thanks,

John

	[[alternative HTML version deleted]]

It depends on the granularity that the operating system is recording
that time; on some systems the minimum might be 0.01 seconds.  If it
is that short, why worry about it.  There is nothing unusual about the
result.

On Wed, Feb 11, 2009 at 7:49 PM, John Kerpel <john.kerpel at gmail.com>
wrote:
> Hi folks!
> Does anyone know why I might see something like this after running
> system.time?
>
> system.time(svd(Mean_svd_data))
>   user  system elapsed
>      0       0       0
>
> The data set is tiny and the function returns results instantly, but
> shouldn't it still give me a time?
>
> Thanks,
>
> John
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?

On Wed, 2009-02-11 at 18:49 -0600, John Kerpel wrote:
> Hi folks!
> Does anyone know why I might see something like this after running
> system.time?
> 
> system.time(svd(Mean_svd_data))
>    user  system elapsed
>       0       0       0
> 
> The data set is tiny and the function returns results instantly, but
> shouldn't it still give me a time?
Jim has already suggested why this might be the case. 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.

HTH

G
> 
> Thanks,
> 
> John
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
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