ConstantFuture

ConstantFuture-class

An R <a rd-options="base" href="/link/expression?package=future&version=1.1.1&to=base" data-mini-rdoc="base::expression">expression</a>.

expr

The <a rd-options="" href="/link/environment?package=future&version=1.1.1" data-mini-rdoc="future::environment">environment</a> in which the evaluation
is done (or inherits from if <code>local</code> is TRUE).

envir

If TRUE, argument <code>expr</code> is
<code><a rd-options="base" href="/link/substitute?package=future&version=1.1.1&to=base" data-mini-rdoc="base::substitute">substitute</a>()</code>:ed, otherwise not.

substitute

If TRUE, the expression is evaluated such that
all assignments are done to local temporary environment, otherwise
the assignments are done in the calling environment.

local


A constant future is a future whose expression is a constant
and therefore by definition already resolved upon creation.


internal

A Future API for R is provided. In programming, a future is an
abstraction for a value that may be available at some point in the future.
The state of a future can either be unresolved or resolved. As soon as it
is resolved, the value is available. Futures are useful constructs in for
instance concurrent evaluation, e.g. parallel processing and distributed
processing on compute clusters. The purpose of this package is to provide
a lightweight interface for using futures in R. Functions 'future()' and
'value()' exist for creating futures and requesting their values, e.g.
'f <- future({ mandelbrot(-0.75, 0, side=3) })' and 'v <- value(f)'. The
'resolved()' function can be used to check if a future is resolved or
not. An infix assignment operator '%<-%' exists for creating futures whose
values are accessible by the assigned variables (as promises), e.g. 'v %<-%
{ mandelbrot(-0.75, 0, side=3) }'. This package implements synchronous "lazy"
and "eager" futures, and asynchronous "multicore", "multisession" and ad hoc
"cluster" futures. Globals variables and functions are automatically identified
and exported. Required packages are attached in external R sessions whenever
needed. All types of futures are designed to behave the same such that the
exact same code work regardless of futures used or number of cores, background
sessions or cluster nodes available. Additional types of futures are provided by
other packages enhancing this package.

Henrik Bengtsson

future

A Future API for R

ConstantFuture-class function

An R <a rd-options='base' href='expression'>expression</a>.

The <a rd-options='' href='environment'>environment</a> in which the evaluation
is done (or inherits from if <code>local</code> is TRUE).

If TRUE, argument <code>expr</code> is
<code><a rd-options='base' href='substitute'>substitute</a>()</code>:ed, otherwise not.

ConstantFuture-class: A future with a constant value

Description

Usage

Arguments

Value