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
Specifies whether a future should be resolved
lazily or eagerly (default).
seed
(optional) A L'Ecuyer-CMRG RNG seed.
globals
A logical, a character vector,
or a named list for controlling how globals are handled.
For details, see below section.
persistent
If FALSE, the evaluation environment is cleared
from objects prior to the evaluation of the future.
workers
The maximum number of multiprocess futures that
can be active at the same time before blocking.
user
(optional) The user name to be used when communicating
with another host.
revtunnel
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.
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.
myip
The external IP address of this machine.
If NULL, then it is inferred using an online service (default).
label
An optional character string label attached to the future.