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Execute all NetLogo simulations from a nl object with a defined experiment and simdesign

Usage

run_nl_all(
  nl,
  split = 1,
  cleanup.csv = TRUE,
  cleanup.xml = TRUE,
  cleanup.bat = TRUE
)

Arguments

nl

nl object

split

number of parts the job should be split into

cleanup.csv

TRUE/FALSE, if TRUE temporary created csv output files will be deleted after gathering results.

cleanup.xml

TRUE/FALSE, if TRUE temporary created xml output files will be deleted after gathering results.

cleanup.bat

TRUE/FALSE, if TRUE temporary created bat/sh output files will be deleted after gathering results.

Value

tibble with simulation output results

Details

run_nl_all executes all simulations of the specified NetLogo model within the provided nl object. The function loops over all random seeds and all rows of the siminput table of the simdesign of nl. The loops are created by calling future_map_dfr, which allows running the function either locally or on remote HPC machines. The logical cleanup variables can be set to FALSE to preserve temporary generated output files (e.g. for debugging). cleanup.csv deletes/keeps the temporary generated model output files from each run. cleanup.xml deletes/keeps the temporary generated experiment xml files from each run. cleanup.bat deletes/keeps the temporary generated batch/sh commandline files from each run.

When using run_nl_all in a parallelized environment (e.g. by setting up a future plan using the future package), the outer loop of this function (random seeds) creates jobs that are distributed to available cores of the current machine. The inner loop (siminputrows) distributes simulation tasks to these cores. However, it might be advantageous to split up large jobs into smaller jobs for example to reduce the total runtime of each job. This can be done using the split parameter. If split is > 1 the siminput matrix is split into smaller parts. Jobs are created for each combination of part and random seed. If the split parameter is set such that the siminput matrix can not be splitted into equal parts, the procedure will stop and throw an error message.

Debugging "Temporary simulation output file not found" error message:

Whenever this error message appears it means that the simulation did not produce any output. Two main reasons can lead to this problem, either the simulation did not even start or the simulation crashed during runtime. Both can happen for several reasons and here are some hints for debugging this:

  1. Missing software: Make sure that java is installed and available from the terminal (java -version). Make sure that NetLogo is installed and available from the terminal.

  2. Wrong path definitions: Make sure your nlpath points to a folder containing NetLogo. Make sure your modelpath points to a *.nlogo model file. Make sure that the nlversion within your nl object matches the NetLogo version of your nlpath. Use the convenience function of nlrx for checking your nl object (print(nl), eval_variables_constants(nl)).

  3. Temporary files cleanup: Due to automatic temp file cleanup on unix systems temporary output might be deleted. Try reassigning the default temp folder for this R session (the unixtools package has a neat function).

  4. NetLogo runtime crashes: It can happen that your NetLogo model started but failed to produce output because of a NetLogo runtime error. Make sure your model is working correctly or track progress using print statements. Sometimes the java virtual machine crashes due to memory constraints.

Examples

if (FALSE) {

# Load nl object from test data:
nl <- nl_lhs

# Execute all simulations from an nl object with properly attached simdesign.
results <- run_nl_all(nl)

# Run in parallel on local machine:
library(future)
plan(multisession)
results <- run_nl_all(nl)

}