[R] multiple R sessions from one working directory using GNU screen

[Olga Lyashevska]

Dear Steven,

Thanks for your post. It explains a lot.
The reason I wanted to use multiple sessions simultaneously is that
because when I run something it usually takes quite a while (calculating
distance matrices), meaning that I have to wait before R can handle the
next task. Also RAM is reaching its limits quite often resulting in
shutdown, so I wanted to split one task into pieces which indeed similar
to cluster computing. I will check documentation on this topic. 

Kind regards,
Olga
  

On Tue, 2010-08-03 at 13:04 -0700, Steven McKinney wrote: 
> Dear Olga

> An R session is conducted entirely in the RAM memory of your computer,
> and each invocation of R will have its own memory space, not shared
> with any other application, including another R session.
> 
> You will have to architect a scheme to allow one R session to find out
> about events and objects in another R session.  This might involve writing
> files to disk from session R1, having session R2 check the directory
> for new files every now and then, and so on.  (save.image() saves
> objects from one R session to a file on disk, but there can be other items
> in the saved file such as environments that are not straightforward
> to manipulate or investigate from another R session.)
> 
> Your situation is similar to cluster computing, where a task is broken up
> into independent pieces and each piece is handled by a separate R process.
> Reading about cluster computing with R might help you figure out
> strategies to share bits of data and information across multiple R sessions.
> 
> HTH
> 
> 
> Steven McKinney
> ________________________________________
> From: r-help-bounces at r-project.org [r-help-bounces at r-project.org] On Behalf Of Olga Lyashevska [olga at herenstraat.nl]
> Sent: August 3, 2010 8:04 AM
> To: r-help at r-project.org
> Cc: Olga Lyashevska
> Subject: [R] multiple R sessions from one working directory using GNU screen
> 
> Dear all,
> 
> I am using GNU screen to run multiple R sessions from one working
> directory in order to split task, however I noticed that dataset is not
> synchronized e.g. if I have two sessions R1 and R2, and I remove an
> object from R1, R2 doesn't change as expected or change at random.
> I have tried to save.image(), q() and then restart both sessions, but it
> does not help.
> 
> 
> Any suggestions?
> 
> Many thanks
> Olga
> 
> R version 2.11.1 (2010-05-31)
> 2010 x86_64 GNU/Linux
> Ubuntu 10.04.1 LTS
> Intel(R) Xeon(R) CPU X3220 @ 2.40GHz
> MemTotal: 4050180 kB
> 
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