Future-class {future} | R Documentation |
A future is an abstraction for a value that may
available at some point in the future. A future can either be
unresolved
or resolved
, a state which can be checked
with resolved()
. As long as it is unresolved, the
value is not available. As soon as it is resolved, the value
is available via value()
.
Future(expr = NULL, envir = parent.frame(), substitute = FALSE, stdout = TRUE, conditions = "condition", globals = NULL, packages = NULL, seed = NULL, lazy = FALSE, local = TRUE, gc = FALSE, earlySignal = FALSE, label = NULL, ...)
expr |
An R expression. |
envir |
The environment from where global objects should be identified. |
substitute |
If TRUE, argument |
stdout |
If TRUE (default), then the standard output is captured,
and re-outputted when |
conditions |
A character string of conditions classes to be captured
and relayed. The default is to relay messages and warnings.
To not intercept conditions, use |
globals |
(optional) a logical, a character vector, or a named list
to control how globals are handled.
For details, see section 'Globals used by future expressions'
in the help for |
packages |
(optional) a character vector specifying packages to be attached in the R environment evaluating the future. |
seed |
(optional) A L'Ecuyer-CMRG RNG seed. |
lazy |
If |
local |
If TRUE, the expression is evaluated such that all assignments are done to local temporary environment, otherwise the assignments are done to the global environment of the R process evaluating the future. |
gc |
If TRUE, the garbage collector run (in the process that
evaluated the future) only after the value of the future is collected.
Exactly when the values are collected may depend on various factors such
as number of free workers and whether |
earlySignal |
Specified whether conditions should be signaled as soon as possible or not. |
label |
An optional character string label attached to the future. |
... |
Additional named elements of the future. |
A Future object is itself an environment.
An object of class Future
.
One function that creates a Future is future()
.
It returns a Future that evaluates an R expression in the future.
An alternative approach is to use the %<-%
infix
assignment operator, which creates a future from the
right-hand-side (RHS) R expression and assigns its future value
to a variable as a promise.