R help - Apr 2013 - parSapply can't find function

Here is the code, assuming 8 cores in the cpu.

library('modeest')
library('snow')

cl = makeCluster(rep('localhost', 8), 'SOCK')
x = vector(length=50)
x = sapply(x, function(i) i=sample(c(1,0), 1))

pastK = function(n, x, k) {
    if (n>k) { return(x[(n-k):(n-1)]) }
    else {return(NA)}
}

predR = function(x, k) {
    pastList = lapply(1:length(x), function(n) pastK(n, x, k))
    pred = sapply(pastList, function(v) mfv(v)[1])
    ratio = sum(pred==x, na.rm=T)/(length(pred) - sum(is.na(pred)))
}

testK = function() {
    k = seq(3, 25, 2)
    r = parSapply(cl, k, function(i) predR(x, i))
#    r = sapply(k, function(i) predR(x, i))
}

r = testK()
stopCluster(cl)

Here is the error:
Error in checkForRemoteErrors(val) :
  8 nodes produced errors; first error: could not find function
"predR"



Best regards,

Kaiyin ZHONG
------------------------------
FMB, Erasmus MC
k.zhong@erasmusmc.nl
kindlychung@gmail.com

	[[alternative HTML version deleted]]

On 18.04.2013 11:11, Kaiyin Zhong (Victor Chung) wrote:
> Here is the code, assuming 8 cores in the cpu.
>
> library('modeest')
> library('snow')
>
> cl = makeCluster(rep('localhost', 8), 'SOCK')
> x = vector(length=50)
> x = sapply(x, function(i) i=sample(c(1,0), 1))
>
> pastK = function(n, x, k) {
>      if (n>k) { return(x[(n-k):(n-1)]) }
>      else {return(NA)}
> }
>
> predR = function(x, k) {
>      pastList = lapply(1:length(x), function(n) pastK(n, x, k))
>      pred = sapply(pastList, function(v) mfv(v)[1])
>      ratio = sum(pred==x, na.rm=T)/(length(pred) - sum(is.na(pred)))
> }
>
> testK = function() {
>      k = seq(3, 25, 2)
>      r = parSapply(cl, k, function(i) predR(x, i))
> #    r = sapply(k, function(i) predR(x, i))
> }
>
> r = testK()
> stopCluster(cl)
>
> Here is the error:
> Error in checkForRemoteErrors(val) :
>    8 nodes produced errors; first error: could not find function
"predR"

predR is not yet known on all nodes, just on the master. You have to 
tell the nodes about the definition first.

Best,
Uwe Ligges



>
>
> Best regards,
>
> Kaiyin ZHONG
> ------------------------------
> FMB, Erasmus MC
> k.zhong at erasmusmc.nl
> kindlychung at gmail.com
>
> 	[[alternative HTML version deleted]]
>
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