Error: Object '.Dosnowglobals' Not Found

R '.doSnowGlobals' not found

The cause of the problem was that I was working on my university computer for which I do not have administrator rights. The randomUniformForest package makes use of parallel processing which uses the IP protocol (even when only one thread is used).

I tried the package on my private computer and it worked fine.

parallel, foreach, exported object not found

You have mixed up some instruction, to make order do this

library(doSNOW)
library(foreach)
cl <- makeCluster(detectCores()-1, type = "SOCK")
registerDoSNOW(cl)

I'm assuming that the object dat was already availaible and so this is how you use the foreach

dumpster <- foreach(i=1:10,.packages=c("copula","np"), .combine = c)%dopar%{dat.new <- some.fn(dat)}

Then close the clusters

stopCluster(cl)

Parallel processing stopped working with error: object 'mcinteractive' not found

This problem occurs because pbmclapply was updated and now only works with R >3.5, updating R solved my problem.

How to set .libPaths (checkpoint) on workers when running parallel computation in R

Author of the future package here.

UPDATE 2022-05-25: As of future 1.20.0 (2021-11-03), multisession parallel workers automatically inherit the R library path (=.libPaths()) from the main R session. Because of this, the below workaround is no longer needed. However, it may still be needed for other future backends.

---

Passing the library path of the master R process as a global variable libs and set it for each worker using .libPaths(libs) should be enough;

## Use CRAN checkpoint from 2018-07-24 to get future (>= 1.9.0) [1],
## otherwise the below stdout won't be relayed back to the master
## R process, but settings .libPaths() does also work in older
## versions of the future package.
## [1] https://cran.microsoft.com/snapshot/2018-07-24/web/packages/future
checkpoint::checkpoint("2018-07-24")
stopifnot(packageVersion("future") >= "1.9.0")

libs <- .libPaths()
print(libs)
### [1] "/home/hb/.checkpoint/2018-07-24/lib/x86_64-pc-linux-gnu/3.5.1"
### [2] "/home/hb/.checkpoint/R-3.5.1"                                 
### [3] "/usr/lib/R/library"

library(foreach)

doFuture::registerDoFuture()
future::plan("multisession")

res <- foreach::foreach(x = unique(iris$Species)) %dopar% {
  ## Use the same library paths as the master R session
  .libPaths(libs)
  
  cat(sprintf("Library paths used by worker (PID %d):\n", Sys.getpid()))
  cat(sprintf(" - %s\n", sQuote(.libPaths())))
      
  stringr::str_c(x, "_")
}

###  - ‘/home/hb/.checkpoint/2018-07-24/lib/x86_64-pc-linux-gnu/3.5.1’
###   - ‘/home/hb/.checkpoint/R-3.5.1’
###   - ‘/usr/lib/R/library’
### Library paths used by worker (PID 9394):
###  - ‘/home/hb/.checkpoint/2018-07-24/lib/x86_64-pc-linux-gnu/3.5.1’
###   - ‘/home/hb/.checkpoint/R-3.5.1’
###   - ‘/usr/lib/R/library’
### Library paths used by worker (PID 9412):
###  - ‘/home/hb/.checkpoint/2018-07-24/lib/x86_64-pc-linux-gnu/3.5.1’
###   - ‘/home/hb/.checkpoint/R-3.5.1’
###   - ‘/usr/lib/R/library’

str(res)
### List of 3
###  $ : chr "setosa_"
###  $ : chr "versicolor_"
###  $ : chr "virginica_"

FYI, it is on future's roadmap to make it easier to pass down the library path(s) to workers.

My details:

> sessionInfo()
R version 3.5.1 (2018-07-02)   
Platform: x86_64-pc-linux-gnu (64-bit)   
Running under: Ubuntu 18.04.1 LTS   

Matrix products: default   
BLAS: /usr/lib/x86_64-linux-gnu/blas/libblas.so.3.7.1   
LAPACK: /usr/lib/x86_64-linux-gnu/lapack/liblapack.so.3.7.1   
  
locale:   
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C               LC_TIME=en_US.UTF-8           LC_COLLATE=en_US.UTF-8     LC_MONETARY=en_US.UTF-8   
 [6] LC_MESSAGES=en_US.UTF-8    LC_PAPER=en_US.UTF-8       LC_NAME=C                     LC_ADDRESS=C               LC_TELEPHONE=C            
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C          
  
attached base packages:   
[1] stats     graphics  grDevices utils     datasets  methods   base        
  
other attached packages:   
[1] foreach_1.4.4   
  
loaded via a namespace (and not attached):   
[1] drat_0.1.4         compiler_3.5.1     BiocManager_1.30.2 parallel_3.5.1        tools_3.5.1        listenv_0.7.0      doFuture_0.6.0    
[8] codetools_0.2-15   iterators_1.0.10   digest_0.6.15      globals_0.12.1        checkpoint_0.4.5   future_1.9.0 

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