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.
Arguments
- sim
A simulation object of class
sim_obj
, usually created bynew_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 Advanced Functionality documentation and 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 beforeset_script
is called.
Examples
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$results %>% print()
# To return complex result data, use the special key ".complex".
sim <- new_sim()
create_data <- function(n) {
x <- runif(n)
y <- 3 + 2*x + rnorm(n)
return(data.frame("x"=x, "y"=y))
}
sim %<>% set_levels("n"=c(10, 100, 1000))
sim %<>% set_config(num_sim=1)
sim %<>% set_script(function() {
dat <- create_data(L$n)
model <- lm(y~x, data=dat)
return (list(
"beta1_hat" = model$coefficients[[2]],
".complex" = model
))
})
sim %<>% run()
sim$results %>% print()
get_complex(sim, 1) %>% print()