[R] Opening more than 1 R console in Windows

[Prof Brian Ripley]

On Sun, 18 May 2008, Anh Tran wrote:

> Hi all,
>
> I recently found out that R does not utilize fully the Duo Core capability
> when you only run one instance of R.

How surprising was that?  Do you have any programs that do?  Very few 
Windows programs make effective use of multiple CPUs, and of those that 
do, they do not do so for the sort of tasks R is running routinely.

> I did some number crunching today and it seems that if I only open 1 R
> console, it uses 50% of my CPU (either 50-50 or 100-0 on 2 cores).
>
> Then, I open the second instance and divide the work into two parts, and run
> them parallelly, they seems to utilize 100% of my CPU.
>
> So, my question would be that: is the computing result the same if I do them
> this way? Will there any mistake compared to running only one instance at a
> time?

Running multiple instances of R simultaneously is very common practice. 
(Right now I have 14 instances running on an 8-core machine.)  The only 
thing you need to watch is that you don't save the workspaces in the same 
place.  So wither run them from different directories or (probably better) 
don't save the workspace.

>
> Thank you all.
>
> -- 
> Regards,
> Anh Tran
>
> 	[[alternative HTML version deleted]]
>
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-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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