A cluster future is a future whose value will be resolved asynchronously in a parallel process
ClusterFuture(expr = NULL, envir = parent.frame(),
substitute = FALSE, globals = TRUE, packages = NULL,
local = !persistent, gc = FALSE, persistent = FALSE,
workers = NULL, user = NULL, master = NULL, revtunnel = TRUE,
homogeneous = TRUE, ...)MultisessionFuture(expr = NULL, envir = parent.frame(),
substitute = FALSE, globals = TRUE, persistent = FALSE,
local = !persistent, workers = NULL, ...)
An R expression.
The environment from where global objects should be identified.
If TRUE, argument expr
is
substitute()
:ed, otherwise not.
(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 future()
.
(optional) a character vector specifying packages to be attached in the R environment evaluating the future.
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.
If TRUE, the garbage collector run (in the process that evaluated the future) after the value of the future is collected. Some types of futures ignore this argument.
If FALSE, the evaluation environment is cleared from objects prior to the evaluation of the future.
A cluster
object,
a character vector of host names, a positive numeric scalar,
or a function.
If a character vector or a numeric scalar, a cluster
object
is created using makeClusterPSOCK(workers)
.
If a function, it is called without arguments when the future
is created and its value is used to configure the workers.
The function should return any of the above types.
(optional) The user name to be used when communicating with another host.
(optional) The hostname or IP address of the master machine running this node.
If TRUE, reverse SSH tunneling is used for the PSOCK cluster nodes to connect back to the master R process. This avoids the hassle of firewalls, port forwarding and having to know the internal / public IP address of the master R session.
If TRUE, all cluster nodes is assumed to use the
same path to Rscript
as the main R session. If FALSE, the
it is assumed to be on the PATH for each node.
Additional named elements passed to Future()
.
ClusterFuture()
returns an object of class ClusterFuture
.
MultisessionFuture()
returns an object of class
MultisessionFuture
, which inherits from ClusterFuture
.
To evaluate an expression using "cluster future", see function
cluster()
.