Run the simulation for one set of parameters

Usage

test_simulation(
  sim_fn,
  scorer_fn,
  ...,
  params = NULL,
  obsdata = NULL,
  seed = NULL,
  debug = FALSE,
  debug_errors = !debug
)

Arguments

sim_fn: a user defined function that takes a set of parameters named the same as priors_list. It must return a simulated data set in the same format as obsdata, or that can be compared to simdata by scorer_fn. This function must not refer to global parameters, and will be automatically crated with carrier.
scorer_fn: a user supplied function that matches the following signature scorer_fn(simdata, obsdata, ....), i.e. it takes data in the format of simdata paired with the original obsdata and returns a named list of component scores per simulation. This function can make use of the calculate_*() set of functions to compare components of the simulation to the original data. This function must not refer to global parameters, and will be automatically crated with carrier. If this is a purrr style function then .x will refer to simulation output and .y to original observation data.
...: simulation parameters, must be named
params: a named list of simulation parameters to test (as an alternative to including them in ...)
obsdata: The observational data. The data in this will typically be a named list, but could be anything, e.g. dataframe. It is the reference data that the simulation model is aiming to replicate.
seed: an optional random seed
debug: start the simulation function in debug mode. This will step through both the sim_fn and the scorer_fn line by line to check that the behaviour is as intended.
debug_errors: Errors that crop up in sim_fn during a simulation due to anomolous value combinations are hard to debug. If this flag is set, whenever a sim_fn or scorer_fn throws an error an interactive debugging session is started with the failing parameter combinations. This is not compatible with running in parallel.

Value

a list containing the parameters as truth and an instance of the simulation as obsdata, obsscores is the result of comparing the obsdata with itself and is usually going to result in zeros. Both sim_fn and scorer_fn are rewritten to make sure that all package names are fully qualified. The rewritten versions are refurned in the result list (as sim_fn and scorer_fn respectively)

Examples

test = test_simulation(
  example_sim_fn,
  example_scorer_fn,
  # Model parameters to test with:
  mean = 4, sd1 = 3, sd2 = 2,
  obsdata = example_obsdata()
)

# the rewritten function:
cat(test$sim_fn, sep="\n")
#> function (mean, sd1, sd2) 
#> {
#>     return(list(A = stats::rnorm(1000, mean, sd1), B = tidyabc::rgamma2(1000, 
#>         mean, sd2)))
#> }

# The scores resulting from this one simulation, when compared to the
# reference `obsdata`.
test$obsscores
#> $A
#> [1] 0.3578723
#> 
#> $B
#> [1] 0.5690237
#>