Is it possible to save and register some previous parallel backend again later?

[privefl]

E.g. some better way to do something like:

library(doParallel)

registerDoParallel(cl1 <- makeCluster(4))
cl_save <- foreach:::getDoPar()$data

registerDoParallel(cl2 <- makeCluster(2))
foreach(ic = 1:10, .combine = 'c') %dopar% { ic }
stopCluster(cl2)

registerDoParallel(cl_save)
foreach(ic = 1:10, .combine = 'c') %dopar% { ic }

stopCluster(cl1)

[privefl]

So basically being able to temporarily register a new backend, but restoring the previously registered one after.

[HenrikBengtsson]

Is FR #19 a generalization of this feature request?

[privefl]

Yes, something like that would help.