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
perfomance.
I use this script:
x<-GiveNextDataPortion()
while(is.null(x)==FALSE)
{
x<-GiveNextDataPortion()
}
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:
x<-GiveNextDataPortion()
i=0
j=1
while(is.null(x)==FALSE)
{
x<-GiveNextDataPortion()
i=i+1
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
>
> ______________________________________________
> R-help@r-project.org mailing list
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> PLEASE do read the posting guide
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> and provide commented, minimal, self-contained, reproducible code.
>
>
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