[R] R perfomance question !!!

diver495 ansolid at gmail.com
Thu Jun 19 08:09:23 CEST 2008

The main task is computing of consistently received data. I have a function
named "GiveNextDataPortion()" that returns the list object. The number of
function's calls is about 5 millions and thus, I encountered a problem of

I use this script:


5 millions iterations of "while" loop takes about 20 seconds on my computer,
it is very quickly, but adding some simple extra operators increases the
time of test a lot. 
For example:

   j= j*i

It will already take more than 10 minutes. 

Have you any ideas about the optimization of this test?

Roland Rau-3 wrote:
> Hi,
> diver495 wrote:
>> Using Visual Basic I can complete the same script (simple loop of 5000000
>> itterations) in 0.1 sec.
>> Is it realy R not suitable for huge computing.
> If you are happy with Visual Basic, then there is no need for you to use
> R.
> In case your message was not a flamebait, it is well known that loops 
> like these are often bottlenecks for R.
> There are many resources how to easily avoid them. See, for example, "S 
> Programming by Venables and Ripley or John Chambers' book: Programming 
> with data.
> Even searching the mail archive for subject like "avoid loops" might be 
> helpful.
> You might also consider checking functions like apply, tapply, ...
> Best,
> Roland
> P.S.
> It seems there is also a good book available for scientific computing 
> with Visual Basic:
> http://www.ibiblio.org/Dave/Dr-Fun/df200002/df20000210.jpg
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