
A remote future is a future that uses remote cluster evaluation, which means that its value is computed and resolved remotely in another process.
remote(expr, envir = parent.frame(), substitute = TRUE, lazy = FALSE,
seed = NULL, globals = TRUE, persistent = TRUE, workers = NULL,
user = NULL, revtunnel = TRUE, gc = FALSE, earlySignal = FALSE,
myip = NULL, label = NULL, ...)
An R expression.
The environment from where global objects should be identified.
If TRUE, argument expr
is
substitute()
:ed, otherwise not.
If FALSE
(default), the future is resolved
eagerly (starting immediately), otherwise not.
(optional) A L'Ecuyer-CMRG RNG seed.
(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()
.
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.
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, 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
is TRUE (more
frequently) or FALSE (less frequently).
Some types of futures ignore this argument.
Specified whether conditions should be signaled as soon as possible or not.
The external IP address of this machine. If NULL, then it is inferred using an online service (default).
An optional character string label attached to the future.
Additional named elements passed to ClusterFuture()
.
The remote
plan is a very similar to the cluster
plan, but provides
more convenient default argument values when connecting to remote machines. Specifically,
remote
uses persistent = TRUE
by default, and it sets homogeneous
,
revtunnel
, and myip
"wisely" depending on the value of workers
.
See below for example on how remote
and cluster
are related.
# NOT RUN {
\donttest{
## Use a remote machine
plan(remote, workers = "remote.server.org")
## Evaluate expression remotely
host %<-% { Sys.info()[["nodename"]] }
host
[1] "remote.server.org"
## The following setups are equivalent:
plan(remote, workers = "localhost")
plan(cluster, workers = "localhost", persistent = TRUE)
plan(cluster, workers = 1L, persistent = TRUE)
plan(multisession, workers = 1L, persistent = TRUE)
## The following setups are equivalent:
plan(remote, workers = "remote.server.org")
plan(cluster, workers = "remote.server.org", persistent = TRUE, homogeneous = FALSE)
## The following setups are equivalent:
cl <- makeClusterPSOCK("remote.server.org")
plan(remote, workers = cl)
plan(cluster, workers = cl, persistent = TRUE)
}
# }
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