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(DiceKriging) design <- expand.grid(x1 = seq(0, 1, length = 15), x2 = seq(0, 1, length = 15)) y <- apply(design, 1, function(x) x[1]^2 + x[2]^2) m <- km(~., design = design, response = data.frame(y = y), multistart = 20) |> futurize() ``` # Introduction This vignette demonstrates how to use **futurize** to parallelize **[DiceKriging]** functions, specifically `km()`. When fitting a kriging model via `km()`, the parameters of the covariance function are estimated by maximum likelihood or cross-validation. The optimization can be started from multiple points (to avoid local optima), which can be done in parallel. ## Example: kriging model with multi-start optimization Fitting a kriging model with a single starting point: ```r library(DiceKriging) design <- expand.grid(x1 = seq(0, 1, length = 15), x2 = seq(0, 1, length = 15)) y <- apply(design, MARGIN = 1, FUN = function(x) x[1]^2 + x[2]^2) m <- km(~., design = design, response = data.frame(y = y)) ``` To run multiple optimizer starts in parallel, set `multistart > 1` and pipe to `futurize()`: ```r library(futurize) library(DiceKriging) design <- expand.grid(x1 = seq(0, 1, length = 15), x2 = seq(0, 1, length = 15)) y <- apply(design, MARGIN = 1, FUN = function(x) x[1]^2 + x[2]^2) m <- km(~., design = design, response = data.frame(y = y), multistart = 20) |> futurize() ``` This distributes the multi-start runs across the available parallel workers, given that we have set up a parallel plan, e.g. ```r plan(multisession) ``` The built-in `multisession` backend parallelizes on your local computer and works on all operating systems. There are [other parallel backends] to choose from, including alternatives to parallelize locally as well as distributed across remote machines, e.g. ```r plan(future.mirai::mirai_multisession) ``` and ```r plan(future.batchtools::batchtools_slurm) ``` # Supported Functions The following **DiceKriging** function is supported by `futurize()`: * `km()` [DiceKriging]: https://cran.r-project.org/package=DiceKriging [other parallel backends]: https://www.futureverse.org/backends.html