R help - Sep 2013 - 'snow' package -- parallel process

Hi R-community:
I heard 'snow' package is a good tool to parallelize processes and speed
them up. I tried to use it but was not successful. Could someboy point where I
was wrong? Thanks.
I want to read a HUGE file to R and hope 'snow' helps me to speed it up.
Here are codes:
library(snow)

iFile = 'BIG.FILE.txt'

numCluster = 4;
readFile = function(file)
{
    orig_d = read.delim(file);
    orig_d;
}
cl = makeCluster(numCluster, type = "SOCK");
x = clusterApply(cl, readFile, iFile);

I got the error

Error in x[[i]] : object of type 'closure' is not subsettable

I also tried to read multiple files once

filenames = rep(iFile, numCluster);
x = clusterApply(cl, readFile, filenames);
stopCluster(cl);

and got the same error

Thanks you for your help.
HXD






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On 04/09/2013 18:57, Hui Du wrote:
>
>
> Hi R-community:
> I heard 'snow' package is a good tool to parallelize processes and
speed them up. I tried to use it but was not successful. Could someboy point
where I was wrong? Thanks.
> I want to read a HUGE file to R and hope 'snow' helps me to speed
it up. Here are codes:
Why are you not using package 'parallel'?

But read the help for clusterApply: you have the arguments wrong.

And please do read the 'R Data Import/Export' manual and get read.delim 
working optimally first.
> library(snow)
>
> iFile = 'BIG.FILE.txt'
>
> numCluster = 4;
> readFile = function(file)
> {
>      orig_d = read.delim(file);
>      orig_d;
> }
> cl = makeCluster(numCluster, type = "SOCK");
> x = clusterApply(cl, readFile, iFile);
>
> I got the error
>
> Error in x[[i]] : object of type 'closure' is not subsettable
>
> I also tried to read multiple files once
>
> filenames = rep(iFile, numCluster);
> x = clusterApply(cl, readFile, filenames);
> stopCluster(cl);
>
> and got the same error
>
> Thanks you for your help.
> HXD
>
>
>
>
>
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
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> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

-- 
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)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595