R: Create a multiprocess future whose value will be resolved...

multiprocess {future}

R Documentation

Create a multiprocess future whose value will be resolved asynchronously using multicore or a multisession evaluation

Description

A multiprocess future is a future that uses multicore evaluation if supported, otherwise it uses multisession evaluation. Regardless, its value is computed and resolved in parallel in another process.

Usage

multiprocess(expr, envir = parent.frame(), substitute = TRUE,
  lazy = FALSE, seed = NULL, globals = TRUE, workers = availableCores(),
  gc = FALSE, earlySignal = FALSE, label = NULL, ...)

Arguments

`expr`	An R expression to be evaluated.
`envir`	The environment from where global objects should be identified. Depending on the future strategy (the `evaluator`), it may also be the environment in which the expression is evaluated.
`substitute`	If TRUE, argument `expr` is `substitute()`:ed, otherwise not.
`lazy`	If `FALSE` (default), the future is resolved eagerly (immediately), otherwise not.
`seed`	(optional) A L'Ecuyer-CMRG RNG seed.
`globals`	(optional) a logical, a character vector, or a named list for controlling how globals are handled. For details, see section 'Globals used by future expressions' in the help for `future()`.
`workers`	The maximum number of multiprocess futures that can be active at the same time before blocking.
`gc`	If TRUE, the garbage collector run (in the process that evaluated the future) after the value of the future is collected.
`earlySignal`	Specified whether conditions should be signaled as soon as possible or not.
`label`	An optional character string label attached to the future.
`...`	Not used.

Value

A MultiprocessFuture implemented as either a MulticoreFuture or a MultisessionFuture.

Examples



## Use multiprocess futures
plan(multiprocess)

## A global variable
a <- 0

## Create multicore future (explicitly)
f <- future({
  b <- 3
  c <- 2
  a * b * c
})

## A multiprocess future is evaluated in a separate R process.
## Changing the value of a global variable will not affect
## the result of the future.
a <- 7
print(a)

v <- value(f)
print(v)
stopifnot(v == 0)