Fit an Experiment. — fit_experiment • simChef

Fit Methods in the Experiment across all DGPs for n_reps repetitions and return results from fits.

Usage

fit_experiment(
  experiment,
  n_reps = 1,
  parallel_strategy = c("reps"),
  future.globals = NULL,
  future.packages = NULL,
  future.seed = TRUE,
  use_cached = FALSE,
  return_all_cached_reps = FALSE,
  save = FALSE,
  checkpoint_n_reps = 0,
  verbose = 1,
  ...
)

Arguments

experiment: An Experiment object.
n_reps: The number of replicates of the Experiment for this run.
parallel_strategy: A vector with some combination of "reps", "dgps", or "methods". Determines how computation will be distributed across available resources. Currently only the default, "reps", is supported.
future.globals: Character vector of names in the global environment to pass to parallel workers. Passed as the argument of the same name to future.apply::future_lapply and related functions. To set for all runs of the experiment, use the same argument during initialization.
future.packages: Character vector of packages required by parallel workers. Passed as the argument of the same name to future.apply::future_lapply and related functions. To set for all runs of the experiment, use the same argument during initialization.
future.seed: Passed as the argument of the same name in future.apply::future_apply.
use_cached: Logical. If TRUE, find and return previously saved results. If cached results cannot be found, continue as if use_cached was FALSE.
return_all_cached_reps: Logical. If FALSE (default), returns only the fit results for the requested n_reps. If TRUE, returns fit results for the requested n_reps plus any additional cached replicates from the (DGP, Method) combinations in the Experiment.
save: If TRUE, save outputs to disk.
checkpoint_n_reps: The number of experiment replicates to compute before saving results to disk. If 0 (the default), no checkpoints are saved.
verbose: Level of verbosity. Default is 1, which prints out messages after major checkpoints in the experiment. If 2, prints additional debugging information for warnings and messages from user-defined functions (in addition to error debugging information). If 0, no messages are printed other than user-defined function error debugging information.
...: Additional future.* arguments to pass to future.apply functions. See future.apply::future_lapply() and future.apply::future_mapply().

Value

A tibble containing the results from fitting all Methods

across all DGPs for n_reps repetitions. In addition to results columns, has columns named '.rep', '.dgp_name', '.method_name', and the vary_across parameter names if applicable.

Examples

## create toy DGPs, Methods, Evaluators, and Visualizers

# generate data from normal distribution with n samples
normal_dgp <- create_dgp(
  .dgp_fun = function(n) rnorm(n), .name = "Normal DGP", n = 10
)
# generate data from binomial distribution with n samples
bernoulli_dgp <- create_dgp(
  .dgp_fun = function(n) rbinom(n, 1, 0.5), .name = "Bernoulli DGP", n = 10
)

# compute mean of data
mean_method <- create_method(
  .method_fun = function(x) list(mean = mean(x)), .name = "Mean(x)"
)

# evaluate SD of mean(x) across simulation replicates
sd_mean_eval <- create_evaluator(
  .eval_fun = function(fit_results, vary_params = NULL) {
    group_vars <- c(".dgp_name", ".method_name", vary_params)
    fit_results %>%
      dplyr::group_by(dplyr::across(tidyselect::all_of(group_vars))) %>%
      dplyr::summarise(sd = sd(mean), .groups = "keep")
  },
  .name = "SD of Mean(x)"
)

# plot SD of mean(x) across simulation replicates
sd_mean_plot <- create_visualizer(
  .viz_fun = function(fit_results, eval_results, vary_params = NULL,
                      eval_name = "SD of Mean(x)") {
    if (!is.null(vary_params)) {
      add_aes <- ggplot2::aes(
        x = .data[[unique(vary_params)]], y = sd, color = .dgp_name
      )
    } else {
      add_aes <- ggplot2::aes(x = .dgp_name, y = sd)
    }
    plt <- ggplot2::ggplot(eval_results[[eval_name]]) +
      add_aes +
      ggplot2::geom_point()
    if (!is.null(vary_params)) {
      plt <- plt + ggplot2::geom_line()
    }
    return(plt)
  },
  .name = "SD of Mean(x) Plot"
)

# initialize experiment with toy DGPs, Methods, Evaluators, and Visualizers
experiment <- create_experiment(
  name = "Experiment Name",
  dgp_list = list(`Normal DGP` = normal_dgp, `Bernoulli DGP` = bernoulli_dgp),
  method_list = list(`Mean(x)` = mean_method),
  evaluator_list = list(`SD of Mean(x)` = sd_mean_eval),
  visualizer_list = list(`SD of Mean(x) Plot` = sd_mean_plot)
)

# initialize empty experiment with user-defined directory for saving results
experiment <- create_experiment(
  name = "Experiment Name",
  dgp_list = list(`Normal DGP` = normal_dgp, `Bernoulli DGP` = bernoulli_dgp),
  method_list = list(`Mean(x)` = mean_method),
  evaluator_list = list(`SD of Mean(x)` = sd_mean_eval),
  visualizer_list = list(`SD of Mean(x) Plot` = sd_mean_plot),
  save_dir = 'path/to/directory'
)

# initialize experiment with toy DGPs, Methods, Evaluators, and Visualizers
# using piping %>%
experiment <- create_experiment(name = "Experiment Name") %>%
  add_dgp(normal_dgp) %>%
  add_dgp(bernoulli_dgp) %>%
  add_method(mean_method) %>%
  add_evaluator(sd_mean_eval) %>%
  add_visualizer(sd_mean_plot)

# run experiment with 2 replicates
results <- run_experiment(experiment, n_reps = 2)
#> Fitting Experiment Name...
#> 2 reps completed (totals: 2/2) | time taken: 0.045073 minutes
#> ==============================
#> Evaluating Experiment Name...
#> Evaluation completed | time taken: 0.000099 minutes
#> ==============================
#> Visualizing Experiment Name...
#> Visualization completed | time taken: 0.000046 minutes
#> ==============================
# uncomment below to view results
# results

# run experiment with varying number of samples n
experiment <- experiment %>%
  add_vary_across(
    .dgp = c("Normal DGP", "Bernoulli DGP"), n = c(1, 10)
  )
# run vary-across experiment with 2 replicates
results <- run_experiment(experiment, n_reps = 2)
#> Fitting Experiment Name...
#> 2 reps completed (totals: 2/2) | time taken: 0.075115 minutes
#> ==============================
#> Evaluating Experiment Name...
#> Evaluation completed | time taken: 0.000102 minutes
#> ==============================
#> Visualizing Experiment Name...
#> Visualization completed | time taken: 0.000069 minutes
#> ==============================
# uncomment below to view results
# results

# `run_experiment()` above is equivalent to the following sequence of calls
fit_results <- fit_experiment(experiment, n_reps = 2)
#> Fitting Experiment Name...
#> 2 reps completed (totals: 2/2) | time taken: 0.073076 minutes
#> ==============================
eval_results <- evaluate_experiment(experiment, fit_results)
#> Evaluating Experiment Name...
#> Evaluation completed | time taken: 0.000100 minutes
#> ==============================
viz_results <- visualize_experiment(experiment, fit_results, eval_results)
#> Visualizing Experiment Name...
#> Visualization completed | time taken: 0.000069 minutes
#> ==============================

# generate data from all DGPs (and vary across components) in experiment
data_out <- generate_data(experiment, n_reps = 1)