[R] cluster/snow question

[Markus Schmidberger]

Hi Tolga,

I am not sure why ls() is showing only "args" and "fun".

But x is at the nodes. Try this:

clusterEvalQ(cl,x<-x+3)
[[1]]
[1] 4

[[2]]
[1] 4

clusterCall(cl,function()x+5)
[[1]]
[1] 9

[[2]]
[1] 9

Best
Markus



tolga.i.uzuner at jpmorgan.com schrieb:
> Dear R Users,
>
> Apologies for a somewhat basic cluster question. I am trying to come to 
> grips with how variables are instantiated within the environment of each 
> node in a cluster. When I run the following code, I expect to see the 
> variable "x" in the environment of each node, but fail to do so. What am I 
> doing wrong ?
>
> library(snow)
> noclusters<-2
> cl <- makeCluster(noclusters, type = "SOCK")
> clusterCall(cl,ls)
> x<-1
> clusterExport(cl,"x")
> clusterCall(cl,ls) #expect to see x in the environment, but get back the 
> same result as in the call above
> stopCluster(cl)
>
>   
>> library(snow)
>> noclusters<-2
>> cl <- makeCluster(noclusters, type = "SOCK")
>> clusterCall(cl,ls)
>>     
> [[1]]
> [1] "args" "fun" 
>
> [[2]]
> [1] "args" "fun" 
>
>   
>> x<-1
>> clusterExport(cl,"x")
>> clusterCall(cl,ls) #expect to see x in the environment
>>     
> [[1]]
> [1] "args" "fun" 
>
> [[2]]
> [1] "args" "fun" 
>
>   
>> stopCluster(cl)
>>
>>     
>
> Thanks in advance,
> Tolga
>
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-- 
Dipl.-Tech. Math. Markus Schmidberger

Ludwig-Maximilians-Universität München
IBE - Institut für medizinische Informationsverarbeitung,
Biometrie und Epidemiologie
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Mail: Markus.Schmidberger [at] ibe.med.uni-muenchen.de
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