A Future for R: Available Future Backends

The future package comes with built-in future backends that leverage the parallel package part of R itself. In addition to these backends, others exist in package extensions, e.g. future.callr, future.mirai, and future.batchtools. Below is an overview of the most common backends that you as an end-user can chose from.

Package / Backend Features How futures are evaluated
future
sequential
📶
♻️
sequentially and in the current R process; default
Example: plan(sequential)
future
multisession
📶
♻️
parallelly via background R sessions on current machine
Examples: plan(multisession) and plan(multisession, workers = 2)
future
cluster
📶
♻️*
parallelly in external R sessions on current, local, and/or remote machines
Examples: plan(cluster, workers = "raspberry-pi"), plan(cluster, workers = c("localhost", "n1", "n1", "pi.example.org"))
future
multicore
📶
♻️
(not recommended) parallelly via forked R processes on current machine; not with GUIs like RStudio; not on Windows
Examples: plan(multicore) and plan(multicore, workers = 2)
future.callr
callr
📶(next)
♻️(next)
parallelly via transient callr background R sessions on current machine; all memory is returned when as each future is resolved
Examples: plan(callr) and plan(callr, workers = 2)
future.mirai
mirai_multisession
📶(next)
♻️(next)
parallelly via mirai background R sessions on current machine; low latency
Examples: plan(mirai_multisession) and plan(mirai_multisession, workers = 2)
future.mirai
mirai_cluster
♻️(next)
parallelly via mirai daemons running locally or remotely
Example: plan(mirai_cluster)
future.batchtools
batchtools_lsf
batchtools_openlava
batchtools_sge
batchtools_slurm
batchtools_torque
📶(soon)
♻️(soon)
parallelly on HPC job schedulers (Load Sharing Facility [LSF], OpenLava, TORQUE/PBS, Son/Sun/Oracle/Univa Grid Engine [SGE], Slurm) via batchtools; for long-running tasks; high latency

📶: futures relay progress updates in real-time, e.g. progressr
♻️: futures are interruptible and restartable; * interrupts are disabled by default
(next): next release; (soon): in a near-future release