simulate_design {DeclareDesign}

Simulate a design

Description

Runs many simulations of a design and returns a simulations data.frame. Speed gains can be achieved by running simulate_design in parallel, see Examples.

Usage

simulate_design(
  ...,
  sims = 500,
  future.seed = requireNamespace("future", quietly = TRUE)
)

simulate_designs(
  ...,
  sims = 500,
  future.seed = requireNamespace("future", quietly = TRUE)
)

Arguments

...

A design created using the + operator, or a set of designs. You can also provide a single list of designs, for example one created by expand_design.

sims

The number of simulations, defaulting to 500. If sims is a vector of the form c(10, 1, 2, 1) then different steps of a design will be simulated different numbers of times.

future.seed

Option for parallel diagnosis via the function future_lapply. A logical or an integer (of length one or seven), or a list of length(X) with pre-generated random seeds. By default, this is set to TRUE if the future and future.apply packages are installed, and FALSE if not. For details, see ?future_lapply.

Details

Different steps of a design may each be simulated different a number of times, as specified by sims. In this case simulations are grouped into "fans". The nested structure of simulations is recorded in the dataset using a set of variables named "step_x_draw." For example if sims = c(2,1,1,3) is passed to simulate_design, then there will be two distinct draws of step 1, indicated in variable "step_1_draw" (with values 1 and 2) and there will be three draws for step 4 within each of the step 1 draws, recorded in "step_4_draw" (with values 1 to 6).

Examples

# Two-arm randomized experiment
design <-
  declare_model(
    N = 500,
    gender = rbinom(N, 1, 0.5),
    X = rep(c(0, 1), each = N / 2),
    U = rnorm(N, sd = 0.25),
    potential_outcomes(Y ~ 0.2 * Z + X + U)
  ) +
  declare_inquiry(ATE = mean(Y_Z_1 - Y_Z_0)) +
  declare_sampling(S = complete_rs(N = N, n = 200)) +
  declare_assignment(Z = complete_ra(N = N, m = 100)) +
  declare_measurement(Y = reveal_outcomes(Y ~ Z)) +
  declare_estimator(Y ~ Z, inquiry = "ATE")

## Not run: 
# Simulate design
simulations <- simulate_design(design, sims = 100)
simulations

# Diagnose design using simulations
diagnosis <- diagnose_design(simulations_df = simulations)
diagnosis

# Simulate one part of the design for a fixed population
# (The 100 simulates different assignments)
head(simulate_design(design, sims = c(1, 1, 1, 100, 1, 1)))

# You may also run simulate_design in parallel using 
#   the future package on a personal computer with multiple
#   cores or on high performance computing clusters. 

library(future)
options(parallelly.fork.enable = TRUE) # required for use in RStudio
plan(multicore) # note other plans are possible, see future

simulate_design(design, sims = 500)


## End(Not run)