set_config {SimEngine}

Modify the simulation configuration

Description

This function sets configuration options for the simulation. If the 'packages' argument is specified, all packages will be loaded and attached via library when set_config is called. Multiple calls to set_config will only overwrite configuration options that are specified in the subsequent calls, leaving others in place. You can see the current configuration via print(sim), where sim is your simulation object.

Usage

set_config(
  sim,
  num_sim = 1000,
  parallel = FALSE,
  n_cores = NA,
  packages = NULL,
  stop_at_error = FALSE,
  progress_bar = TRUE,
  seed = as.integer(1e+09 * runif(1)),
  batch_levels = NA,
  return_batch_id = FALSE
)

Arguments

sim

A simulation object of class sim_obj, usually created by new_sim

num_sim

An integer; the number of simulations to conduct for each level combination

parallel

Boolean; if set to TRUE, SimEngine will run one simulation per core. if set to FALSE, code will not be parallelized. See the Parallelization vignette for an overview of how parallelization works in SimEngine.

n_cores

An integer; determines the number of cores on which the simulation will run if using parallelization. Defaults to one fewer than the number of available cores.

packages

A character vector of packages to load and attach

stop_at_error

Boolean; if set to TRUE, the simulation will stop if it encounters an error in any single replicate Useful for debugging.

progress_bar

Boolean; if set to FALSE, the progress bar that is normally displayed while the simulation is running is suppressed.

seed

An integer; seeds allow for reproducible simulation results. If a seed is specified, then consecutive runs of the same simulation with the same seed will lead to identical results (under normal circumstances). If a seed was not set in advance by the user, SimEngine will set a random seed, which can later be retrieved using the vars function. See details for further info.

batch_levels

Either NULL or a character vector. If the batch function is being used within the simulation script, this should contain the names of the simulation levels that are used within the batch function code block. If no simulation levels are used within the batch function code block, specify NULL. See the documentation for the batch function.

return_batch_id

Boolean. If set to TRUE, the batch_id will be included as part of the simulation results

Details

• If a user specifies, for example, set_config(seed=4), this seed is used twice by SimEngine. First, SimEngine executes set.seed(4) at the end of the set_config call. Second, this seed is used to generate a new set of seeds, one for each simulation replicate. Each of these seeds is set in turn (or in parallel) when run is called.

• Even if seeds are used, not all code will be reproducible. For example, a simulation that involves getting the current date/time with Sys.time or dynamically retrieving external data may produce different results on different runs.

Value

The original simulation object with a modified configuration

Examples

sim <- new_sim()
sim %<>% set_config(
  num_sim = 10,
  seed = 2112
)
print(sim)