Martin,
I think the main problem is that you are trying to assign your results
to the result matrix inside the foreach loop. Parallel functions in R
are generally not good at updating parts of matrices from the different
workers in this way. Instead, using e.g. foreach, each loop of the
foreach-call has to return a vector which can be cbind-ed to a result
matrix. Something like:
L2distance = foreach(j=1:n1, .combine = cbind) %dopar% {
res = rep(NA, 10)
for (k in j:n1) res[k] = k*data[j]
res
}
L2distance
I am not sure what the np-library is, but you should consider putting it
in a clusterExport-call after creating the cluster.
Best wishes,
Jon
On 7/31/2015 2:39 PM, Martin Spindler wrote:
Dear all,
when I am running the code attached below, it seems that no results are
returned, only the predefined NAs. What mistake do I make?
Any comments and help is highly appreciated.
Thanks and best,
Martin
Simpar3 <- function(n1) {
L2distance <- matrix(NA, ncol=n1, nrow=n1)
data <- rnorm(n1)
diag(L2distance)=0
cl <- makeCluster(4)
registerDoParallel(cl)
foreach(j=1:n1) %dopar% {
library(np)
datj <- data[j]
for(k in j:n1) {
L2distance[j,k] <- k*datj
}
}
stopCluster(cl)
return(L2distance)
}
Res <- Simpar3(100)
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--
Jon Olav Skøien
Joint Research Centre - European Commission
Institute for Environment and Sustainability (IES)
Climate Risk Management Unit
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