Evaluate an Expression using a Temporarily Registered Foreach %dopar% Adapter

Evaluate an Expression using a Temporarily Registered Foreach %dopar% Adapter

Usage

# S3 method for class 'DoPar'
with(data, expr, ..., local = FALSE, envir = parent.frame())

Arguments

data: The foreach %dopar% adapter to use temporarily.
expr: The R expression to be evaluated.
local: If TRUE, then the future plan specified by data is applied temporarily in the calling frame. Argument expr must not be specified if local = TRUE.
envir: The environment where the adapter should be set and the expression evaluated.
...: Not used.

Value

The value of expr if local = FALSE, otherwise NULL invisibly.

Examples

with(registerDoFuture(), {
  y <- foreach(x = 1:3) %dopar% { x^2 }
})
#> [[1]]
#> [1] 1
#> 
#> [[2]]
#> [1] 4
#> 
#> [[3]]
#> [1] 9
#> 

a_fcn_in_a_pkg <- function(xs) {
  foreach(x = xs) %dopar% { x^2 }
}

with(registerDoFuture(flavor = "%dofuture%"), {
  y <- a_fcn_in_a_pkg(1:3)
})
#> [[1]]
#> [1] 1
#> 
#> [[2]]
#> [1] 4
#> 
#> [[3]]
#> [1] 9
#> 


my_fcn <- function(xs) {
  ## Use registerDoFuture() for this function only and then
  ## revert back to the previously set foreach adapter
  with(registerDoFuture(), local = TRUE)
  
  foreach(x = xs) %dopar% { x^2 }
}