A framework for parallelizing dependent tasks

Author: Jeremy Coyle


What’s delayed?

delayed is an R package that provides a framework for parallelizing dependent tasks in an efficient manner. It brings to R a subset of the functionality implemented in Python’s Dask library. For details on how best to use delayed, please consult the package documentation and vignette online, or do so from within R.


Installation

Install the most recent stable release from GitHub via devtools:

devtools::install_github("jeremyrcoyle/delayed")

Issues

If you encounter any bugs or have any specific feature requests, please file an issue.


Example

This minimal example shows how to use delayed to handle dependent computations via chaining of tasks:

library(delayed)
#> delayed: Framework for Parallelizing Dependent Tasks
#> Version: 0.2.1

# delay a function that does a bit of math
mapfun <- function(x, y) {(x + y) / (x - y)}
delayed_mapfun <- delayed_fun(mapfun)

set.seed(14765)
library(future)
plan(multicore, workers = 2)
const <- 7

# re-define the delayed object from above
delayed_norm <- delayed(rnorm(n = const))
delayed_pois <- delayed(rpois(n = const, lambda = const))
chained_norm_pois <- delayed_mapfun(delayed_norm, delayed_pois)

# compute it using the future plan (multicore with 2 cores)
chained_norm_pois$compute(nworkers = 2, verbose = TRUE)
#> run:0 ready:2 workers:2
#> updating rpois(n = const, lambda = const) from ready to running
#> run:1 ready:1 workers:2
#> updating rnorm(n = const) from ready to running
#> run:2 ready:0 workers:2
#> updating rnorm(n = const) from running to resolved
#> updating rpois(n = const, lambda = const) from running to resolved
#> updating mapfun(x = delayed_norm, y = delayed_pois) from waiting to ready
#> run:0 ready:1 workers:2
#> updating mapfun(x = delayed_norm, y = delayed_pois) from ready to running
#> run:1 ready:0 workers:2
#> updating mapfun(x = delayed_norm, y = delayed_pois) from running to resolved
#> [1] -1.4611216 -0.9957879 -1.1672658 -0.1965680 -1.8825711 -0.8601383
#> [7] -0.6723261

Remark: In the above, the delayed computation is carried out in parallel using the framework offered by the excellent future package.


License

© 2017 Jeremy R. Coyle

The contents of this repository are distributed under the GPL-3 license. See file LICENSE for details.