error: object '.doSnowGlobals' not found?

Question

I\'m trying to parallelize a code on 4 nodes(type = \"SOCK\"). Here is my code.

library(itertools)
library(foreach)
library(doParallel)
library(parallel)

wo         


        

Answer 1

To set the library path on each worker you can run:

clusterEvalQ(cl, .libPaths("Your library path"))

Answer 2

A specific case of @Steve Weston's answer is when your workers aren't able to load a given package (eg doParallel) because the package is inside a Packrat project. Install the packages to the system library, or somewhere else that a worker will be able to find them.

Answer 3

You can get this error if any of the workers are unable to load the doParallel package. You can make that happen by installing doParallel into some directory and pointing the master to it via ".libPaths":

> .libPaths('~/R/lib.test')
> library(doParallel)
> cl <- makePSOCKcluster(3, outfile='')
starting worker pid=26240 on localhost:11566 at 13:47:59.470
starting worker pid=26248 on localhost:11566 at 13:47:59.667
starting worker pid=26256 on localhost:11566 at 13:47:59.864
> registerDoParallel(cl)
> foreach(i=1:10) %dopar% i
Warning: namespace ‘doParallel’ is not available and has been replaced
by .GlobalEnv when processing object ‘’
Warning: namespace ‘doParallel’ is not available and has been replaced
by .GlobalEnv when processing object ‘’
Warning: namespace ‘doParallel’ is not available and has been replaced
by .GlobalEnv when processing object ‘’
Error in checkForRemoteErrors(lapply(cl, recvResult)) : 
  3 nodes produced errors; first error: object '.doSnowGlobals' not found

The warning happens when a function from doParallel is deserialized on a worker. The error happens when the function is executed and tries to access .doSnowGlobal which is defined in the doParallel namespace, not in .GlobalEnv.

You can also verify that doParallel is available on the workers by executing:

> clusterEvalQ(cl, library(doParallel))
Error in checkForRemoteErrors(lapply(cl, recvResult)) : 
  3 nodes produced errors; first error: there is no package called ‘doParallel’

Answer 4

I encountered the same problem today, and I tried all the answers above, none of which worked for me. Then I simply reinstalled the doSNOW package, and magically, the problem was solved.