Reproducibility (II)

We will slightly modify the first exercise of this chapter and ask the same question. We ran the following code in your workspace:

library(doParallel)
library(doRNG)
cl <- makeCluster(2)
registerDoParallel(cl)
registerDoRNG(100)

Is the following code reproducible on a cluster of any size and why?

set.seed(100)
res <- foreach (i = 1:3) %dopar% rnorm(3)

Yes. It registers the L'Ecuyer RNG, sets its seed and each node has its own independent stream.
No. There is one stream per node instead of per task.
No. It sets the seed only on the master process.
Yes. It registers the L'Ecuyer RNG, sets its seed and each replication uses its own stream.