set_script: Set the "simulation script"

In SimEngine: A Modular Framework for Statistical Simulations in R

Set the "simulation script"

Description

Specify a function to be used as the "simulation script". The simulation script is a function that runs a single simulation replicate and returns the results.

Usage

set_script(sim, fn)

Arguments

sim

A simulation object of class sim_obj, usually created by new_sim

fn

A function that runs a single simulation replicate and returns the results. The results must be a list of key-value pairs. Values are categorized as simple (a number, a character string, etc.) or complex (vectors, dataframes, lists, etc.). Complex data must go inside a key called ".complex" and the associated value must be a list (see examples). The function body can contain references to the special object L that stores the current set of simulation levels (see examples). The keys must be valid R names (see ?make.names). Any functions used within the script must be declared before set_script is called.

Value

The original simulation object with the new "simulation script" function added.

Examples

# The following is a toy example of a simulation, illustrating the use of
# the set_script function.
sim <- new_sim()
create_data <- function(n) { rpois(n, lambda=5) }
est_mean <- function(dat, type) {
  if (type=="M") { return(mean(dat)) }
  if (type=="V") { return(var(dat)) }
}
sim %<>% set_levels(n=c(10,100,1000), est=c("M","V"))
sim %<>% set_config(num_sim=1)
sim %<>% set_script(function() {
  dat <- create_data(L$n)
  lambda_hat <- est_mean(dat=dat, type=L$est)
  return (list("lambda_hat"=lambda_hat))
})
sim %<>% run()
sim$results

# If you need to return complex result data (vectors, dataframes, lists,
# etc.), use the construct ".complex"=list().
sim <- new_sim()
sim %<>% set_levels(n=c(4,9))
sim %<>% set_config(num_sim=1)
sim %<>% set_script(function() {
  dat <- rnorm(L$n)
  mtx <- matrix(dat, nrow=sqrt(length(dat)))
  return (list(
    "mean" = mean(dat),
    "det" = det(mtx),
    ".complex" = list(dat=dat, mtx=mtx)
  ))
})
sim %<>% run()

SimEngine documentation built on Oct. 27, 2023, 1:07 a.m.