Question about output the objects on slave by SNOW

'cat' and 'print' work from the workers, but the
output is redirected to /dev/null (or NUL:) by
default.  If you set the 'outfile' option to an
empty string when creating the cluster object,
then output won't be redirected in the workers,
and will generally be displayed in your session.

For example:

f <- function(iter,x) {

+   y <- sin(x)
+   cat('x=', x,'\n')
+   return(y)
+ }

library(snow)
cl <- makeSOCKcluster(2, outfile="")

starting worker for localhost:10187
starting worker for localhost:10187

clusterExport(cl, ls())

Type: EXEC
Type: EXEC
Type: EXEC
Type: EXEC

parSapply(cl,1:2,f,1)

Type: EXEC
x= 1
Type: EXEC
x= 1
[1] 0.841471 0.841471


The output can be a bit jumbled, and it includes
other output generated by the workers, but I find it
very useful for debugging.

- Steve

Hi all,

I am using SNOW package on my multi-core Windows machine. I am wondering if
there is a way to output the objects on slave, as far as I know 'cat' or
'print' doesn't work. One simple example:

f<-function(iter,x) {

+ y=sin(x)
+ cat('x=', x,'\n')
+ return(y)
+ }

library(snow)
cl<-makeCluster(2)
clusterExport(cl,ls())

parSapply(cl,1:2,f,1)

[1] 0.841471 0.841471

I would like to get the information about 'x', like this,

sapply(1:2,f,1)

x= 1
x= 1
[1] 0.841471 0.841471

Thanks,
Libo

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