[R] total CPU time in Matlab - what is the equivalent in R?

[Jan Mueller]

Maybe the unix time command comes in handy (provided you work with linux)?
http://en.wikipedia.org/wiki/Time_(Unix)
Best
Jan


-----Ursprüngliche Nachricht-----
Von: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] Im Auftrag von William Dunlap
Gesendet: Montag, 27. August 2012 16:38
An: Jeff Newmiller; Gopi Goteti; r-help at r-project.org
Betreff: Re: [R] total CPU time in Matlab - what is the equivalent in R?

I didn't notice a discussion of what system or user time meant in those two articles.  (The first correctly says that system.time() is a more convenient way to time things, as it calls proc.time() before and after your expression and subtracts.  It also does garbage collection before the timing, so you get more consistent results.)

CPU time is essentially user time plus system time.   User time is time spent
in R itself.  System time is time spent by the kernel of the operating system doing things that R asked it to do (e.g., finding a file, reading a file, perhaps getting the time).  What is considered system time depends on your operating system.  There is some time spent switching between user and kernel mode and I don't know who gets charged for that time.  Elapsed time is usually what counts in the end.

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com


> -----Original Message-----
> From: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] On Behalf Of Jeff Newmiller
> Sent: Sunday, August 26, 2012 11:13 PM
> To: Gopi Goteti; r-help at r-project.org
> Subject: Re: [R] total CPU time in Matlab - what is the equivalent in R?
> 
> Google is your friend
> 
> http://www.ats.ucla.edu/stat/r/faq/timing_code.htm
> 
> http://r.research.att.com/benchmarks/
> ---------------------------------------------------------------------------
> Jeff Newmiller                        The     .....       .....  Go Live...
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> ----------------------------------------------------------------------
> ----- Sent from my phone. Please excuse my brevity.
> 
> Gopi Goteti <gopi.goteti at gmail.com> wrote:
> 
> >I am trying to compare the speed of my R code with that reported by 
> >the authors of a reference paper who used Matlab. The authors of the 
> >paper state "Total CPU time for the algorithm was 10 s for the ...on 
> >a modest mobile 2.2 GHz Pentium processor running MATLAB v.6".
> >
> >I am using proc.time (similar to the example shown in ?proc.time) to 
> >determine the speed of my R code. Could someone please tell me 
> >whether "user" time or "system" time is the equivalent of total CPU 
> >time reported by Matlab.
> >
> >Thanks
> >GG
> >
> >	[[alternative HTML version deleted]]
> >
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