Controllers: Class of Controller

In TrialSimulator: Clinical Trial Simulator

Class of Controller

Description

Create a class of controller to run a trial.

Public methods in this R6 class are used in developing this package. Thus, we have to export the whole R6 class which exposures all public methods. However, only the public methods in the list below are useful to end users.

• $run() run trial simulation, sequentially or in parallel. It cannot be called twice on a controller unless $reset() is called in between.

• $get_output() return a data frame of all outputs saved during simulation.

• $reset() reset the trial and listener registered to the controller before starting a new simulation with $run().

Value

an R6Class generator object; use controller() to create a controller.

Methods

Public methods

• Controllers$new()

• Controllers$reset()

• Controllers$get_output()

• Controllers$run()

• Controllers$clone()

---

Method new()

initialize a controller of the trial

Usage

Controllers$new(trial, listener)

Arguments

trial

a trial object returned from trial().

listener

a listener object returned from listener().

---

Method reset()

reset the trial and listener registered to the controller so that a new simulation can be started with controller$run(). The trial and the milestones are restored to their as-designed version.

Usage

Controllers$reset()

---

Method get_output()

return a data frame of all current outputs saved by calling save().

Usage

Controllers$get_output(cols = NULL, simplify = TRUE, tidy = FALSE)

Arguments

cols

character vector. Columns to be returned from the data frame of simulation outputs. If NULL, all columns are returned.

simplify

logical. Return vector rather than a data frame of one column when length(cols) == 1 and simplify == TRUE.

tidy

logical. TrialSimulator automatically records a set of standard outputs at milestones, even when doNothing is used as action functions. These includes time of triggering milestones, number of observed events for time-to-event endpoints, and number of non-missing readouts for non-TTE endpoints (see vignette('actionFunctions')). This usually mean a large number of columns in outputs. If users have no intent to summarize a trial on these columns, setting tidy = TRUE can eliminate these columns from get_output(). This is useful to reduced the size of output data frame when a large number of replicates are done for simulation. Note that currently we use regex "^n_events_<.*?>_<.*?>$" and "^milestone_time_<.*?>$" to match columns to be eliminated. If users plan to use tidy = TRUE, caution is needed when naming custom outputs in save(). Default FALSE.

---

Method run()

run trial simulation. It cannot be called again on the same controller unless reset() is called first.

Usage

Controllers$run(
  n = 1,
  n_workers = 1,
  plot_event = TRUE,
  silent = FALSE,
  tidy = FALSE
)

Arguments

n

integer. Number of replicates of simulation. n = 1 by default. Simulation results can be accessed by controller$get_output().

n_workers

integer. Number of parallel workers. When n_workers = 1 (default), replicates are run sequentially. When n_workers > 1, replicates are distributed across parallel workers using the mirai package, which must be installed separately. Each worker receives a serialized copy of the trial and listener objects and runs its share of replicates independently. If any replicate encounters an error, execution stops and already-collected results are preserved in $get_output(). To debug, manually set seed in trial() and n_workers = 1 in run() for reproduced results. Note that optimal n_workers may not be parallel::detectCores(). For example, Macbook with M1/M2/M3 chips may have performance cores and efficiency cores. To achieve the best parallel performance, one may want to use the performance cores only. For a M1 laptop with 4 performance cores, n_workers = 3 may give the best performance.

plot_event

logical. Create event plot if TRUE. Forced to FALSE when n > 1 or n_workers > 1.

silent

logical. TRUE if muting all messages during a trial. Note that warning messages are still displayed. When silent = TRUE and replicates are run sequentially (n_workers = 1), a progress bar is displayed automatically if the simulation is expected to take more than 1 minute.

tidy

logical. If TRUE, the per-arm event count table (output column n_events_<milestone>_<arms>) is not saved at milestones; the per-endpoint totals and milestone times are still saved. Saving that table is the most expensive part of the standard outputs, so tidy = TRUE is recommended for a large number of replicates unless the per-arm counts are needed in the summary. This differs from tidy in $get_output(), which removes all standard columns from the returned data frame after the fact. Default FALSE.

---

Method clone()

The objects of this class are cloneable with this method.

Usage

Controllers$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

Examples

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TrialSimulator documentation built on Sept. 4, 2026, 5:08 p.m.