The **futurize** package allows you to easily turn sequential code into parallel code by piping the sequential code to the `futurize()` function. Easy! # TL;DR ```r library(futurize) plan(multisession) library(stars) m <- matrix(1:20, nrow = 5, ncol = 4) s <- st_as_stars(m) res <- st_apply(s, MARGIN = 1, FUN = mean) |> futurize() ``` # Introduction This vignette demonstrates how to use this approach to parallelize **[stars]** functions such as `st_apply()`. The **[stars]** package provides a framework for "Spatiotemporal Arrays" (raster and vector data cubes). It is a powerful tool for working with large-scale spatial and temporal data. Many operations in **stars**, particularly those involving applying functions across dimensions, can be computationally intensive and thus benefit significantly from parallelization. ## Example: Applying a function across dimensions The `st_apply()` function applies a function to one or more dimensions of a `stars` object. By default, it runs sequentially. By piping the result to `futurize()`, we can easily enable parallel processing. ```r library(futurize) library(stars) ## Create a small stars object m <- matrix(1:10000, nrow = 100, ncol = 100) s <- st_as_stars(m) ## Calculate the mean across the first dimension res <- st_apply(s, MARGIN = 1, FUN = mean) |> futurize() ``` When you pipe a `st_apply()` call to `futurize()`, it automatically configures the internal parallelization mechanism of the **stars** package to use the **future** framework. This ensures that the computation is distributed across the parallel workers defined by your current `plan()`. For example, to parallelize on your local machine: ```r plan(multisession) ``` The **futurize** package handles all the details of setting up the parallel environment, ensuring that global variables and packages are correctly exported to the workers, and that any output or conditions (like messages and warnings) are relayed back to your main R session. # Supported Functions The following **stars** functions are supported by `futurize()`: * `st_apply()` [stars]: https://cran.r-project.org/package=stars