[R] My surprising experience in trying out REvolution's R

Carl Witthoft carl at witthoft.com
Wed Apr 22 23:48:14 CEST 2009


<quote>
 > First, the regular R 1.9. It takes 2 minutes and 6 seconds, CPU usage
 > 50%
 >
 > Next, REvolution's R. It takes 2 minutes and 10 seconds, CPU usage 100%.
 >
 > In other words, REvolution's R consumes double the CPU with slightly
 > less speed.

The fact that it is the same time with only the 50%/100% makes me think 
this is an artifact of the CPU indicator. Try to assign only one CPU to 
the REvolution task. Wild guess: also 2 minutes plus minus

Dieter
</quote>

Yeah, I don't think CPU indicators mean a lot.  I've watched the CPU 
chart in Activity Monitor (OS X)  go to 200% -- and that's on a machine 
that does not have dual processors or dual-core processors.

OTOH,  I'd have to disagree with the folks who suggest REvolution might 
have a lot of set-up overhead.  Unless the example code from the OP has 
a lot of full start/stop behavior,  it's hard to imagine some code that 
is zippy fast but has a set-up time in the double-digit seconds range. 
And that's what would be needed for the times quoted above if REvolution 
were to be processing twice as fast as R.

Carl




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