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The future package provides a generic API for using futures in R. A future is a simple yet powerful mechanism to evaluate an R expression and retrieve its value at some point in time. Futures can be resolved in many different ways depending on which strategy is used. There are various types of synchronous and asynchronous futures to choose from in the future package.
This package, future.mirai, provides a type of futures that utilizes the mirai package.
For example,
> library(future.mirai)
> plan(mirai_multisession)
>
> x %<-% { Sys.sleep(5); 3.14 }
> y %<-% { Sys.sleep(5); 2.71 }
> x + y
1] 5.85 [
This is obviously a toy example to illustrate what futures look like and how to work with them. For further examples on how to use futures, see the vignettes of the future package as well as those of future.apply, furrr, and doFuture.
The future.mirai package implements a future backend wrapper for mirai.
Backend | Description | Alternative in future package |
---|---|---|
mirai_multisession |
parallel evaluation in separate R processes (on current machine) | plan(multisession) |
mirai_cluster |
parallel evaluation in mirai-configured workers | plan(cluster) |
The mirai package provides a low-level future-like mechanism for evaluating R expression in separate R processes running on the local machine or on one or more remote machines. Centrally to mirai is its highly-optimized queueing mechanism, which is used to orchestrate communication between the main R process and parallel workers. A mirai cluster of workers can be configured to communicate securly via the well-established Transport Layer Security (TLS) protocol.
Another advantage with mirai_*
futures, compared to
multisession
and cluster
futures, is that we
can use more than 125 parallel workers. The current limit of 125 workers
for multisession
and cluster
futures stems
from how the underlying parallel package using one R
connection per parallel worker and R has a limit of 125 R connections
per session. In R (>= 4.4.0), we can increase this limit when we
launch R, e.g. R --max-connections=200
. For R (< 4.4.0),
R has to be rebuilt from source after adjusting the source code. The
mirai package does not rely on R connections for
parallel workers and does therefore not suffer from this limit.
The future
package provides a demo using futures for calculating a set of
Mandelbrot planes. The demo does not assume anything about what type of
futures are used. The user has full control of how futures are
evaluated. For instance, to use mirai_multisession
futures, run the demo as:
library(future.mirai)
plan(mirai_multisession)
demo("mandelbrot", package = "future", ask = FALSE)
To use mirai_cluster
futures, use:
library(future.mirai)
::daemons(2)
miraiplan(mirai_cluster)
demo("mandelbrot", package = "future", ask = FALSE)
R package future.mirai is available on CRAN and can be installed in R as:
install.packages("future.mirai")
To install the pre-release version that is available in Git branch
develop
on GitHub, use:
::install_github("futureverse/future.mirai", ref="develop") remotes
This will install the package from source.
These binaries (installable software) and packages are in development.
They may not be fully stable and should be used with caution. We make no claims about them.