[R] parSapply can't find function

[Uwe Ligges]

On 23.04.2013 15:00, Kaiyin Zhong (Victor Chung) wrote:
> Thanks for the reply.
>
> How can i make the functions known to all nodes?

See ?clusterEvalQ

you may also want to try the parallel packages.

Best,
Uwe Ligges



>
> Best regards,
>
> Kaiyin ZHONG
> ------------------------------------------------------------------------
> FMB, Erasmus MC
> k.zhong at erasmusmc.nl <mailto:k.zhong at erasmusmc.nl>
> kindlychung at gmail.com <mailto:kindlychung at gmail.com>
>
>
> On Tue, Apr 23, 2013 at 2:43 PM, Uwe Ligges
> <ligges at statistik.tu-dortmund.de
> <mailto:ligges at statistik.tu-dortmund.de>> wrote:
>
>
>
>     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
>         <http://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 <mailto:k.zhong at erasmusmc.nl>
>         kindlychung at gmail.com <mailto:kindlychung at gmail.com>
>
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