SimWarnings: Extract Simulation Warnings

In SimDesign: Structure for Organizing Monte Carlo Simulation Designs

Extract Simulation Warnings

Description

Extractor function in situations where runSimulation returned a simulation with detected WARNINGS.

Usage

SimWarnings(obj, subset = TRUE)

Arguments

obj	object returned from runSimulation containing an WARNINGS column
subset	logical; take a subset of the design object showing only conditions that returned warnings?

Author(s)

Phil Chalmers [e-mail]

References

Chalmers, R. P., & Adkins, M. C. (2020). Writing Effective and Reliable Monte Carlo Simulations with the SimDesign Package. The Quantitative Methods for Psychology, 16(4), 248-280. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.20982/tqmp.16.4.p248")}

Sigal, M. J., & Chalmers, R. P. (2016). Play it again: Teaching statistics with Monte Carlo simulation. Journal of Statistics Education, 24(3), 136-156. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1080/10691898.2016.1246953")}

See Also

SimErrors, SimExtract

Examples

sample_sizes <- c(10, 20)
standard_deviations <- 1

Design <- createDesign(N1=sample_sizes,
                       N2=sample_sizes,
                       SD=standard_deviations)
Design

Generate <- function(condition, fixed_objects){
    Attach(condition)
    group1 <- rnorm(N1)
    group2 <- rnorm(N2, sd=SD)
    dat <- data.frame(group = c(rep('g1', N1), rep('g2', N2)),
                      DV = c(group1, group2))
    dat
}

# functions to throw warnings
fn1 <- function(){
  if(sample(c(TRUE, FALSE), 1, prob = c(.1, .9))) warning('Show this warning')
  1
 }

fn2 <- function(){
    if(sample(c(TRUE, FALSE), 1, prob = c(.1, .9))) warning('Show a different warning')
    1
}

Analyse <- function(condition, dat, fixed_objects){
  if(with(condition, N1 != N2)){
    out1 <- fn1()
    out2 <- fn2()
  }
  c(ret = 1)
}

Summarise <- function(condition, results, fixed_objects) {
  ret <- colMeans(results)
  ret
}

# print warning messages and their frequency
res <- runSimulation(design=Design, replications=10, generate=Generate,
                     analyse=Analyse, summarise=Summarise)
res |> select(N1, N2, SD, WARNINGS)
SimWarnings(res)
SimWarnings(res, subset=FALSE)

SimDesign documentation built on July 28, 2026, 1:07 a.m.