irace (version 4.1)

ablation: Performs ablation between two configurations (from source to target).

Description

Ablation is a method for analyzing the differences between two configurations.

Usage

ablation(
  iraceResults,
  src = 1L,
  target = NULL,
  ab_params = NULL,
  type = c("full", "racing"),
  nrep = 1L,
  seed = 1234567L,
  ablationLogFile = "log-ablation.Rdata",
  instancesFile = "train",
  ...
)

Value

A list containing the following elements:

configurations

Configurations tested in the ablation.

instances

A matrix with the instances used in the experiments. First column has the instances IDs from iraceResults$scenario$instances, second column the seed assigned to the instance.

experiments

A matrix with the results of the experiments (columns are configurations, rows are instances).

scenario

Scenario object with the settings used for the experiments.

trajectory

IDs of the best configurations at each step of the ablation.

best

Best configuration found in the experiments.

Arguments

iraceResults

list()|character(1)
Object created by irace and typically saved in the log file irace.Rdata. If a character string is given, then it is interpreted as the path to the log file from which the iraceResults object will be loaded.

src, target

integer(1)|character(1)
Source and target configuration IDs. By default, the first configuration ever evaluated (ID 1) is used as src and the best configuration found by irace is used as target. If the argument is a string, it is interpreted as the path to a file, with the format specified by readConfigurationsFile(), that contains the configuration.

ab_params

character()
Specific parameter names to be used for the ablation. They must be in parameters$names. By default, use all parameters.

type

"full"|"racing"
Type of ablation to perform: "full" will execute each configuration on all n_instances to determine the best-performing one; "racing" will apply racing to find the best configurations.

nrep

integer(1)
Number of replications per instance used in "full" ablation. When nrep > 1, each configuration will be executed nrep times on each instance with different random seeds.

seed

integer(1)
Integer value to use as seed for the random number generation.

ablationLogFile

character(1)
Log file to save the ablation log. If NULL, the results are not saved to a file.

instancesFile

character(1)
Instances file used for ablation: 'train', 'test' or a filename containing the list of instances.

...

Further arguments to override scenario settings, e.g., debugLevel, parallel, etc.

Author

Leslie Pérez Cáceres and Manuel López-Ibáñez

References

C. Fawcett and H. H. Hoos. Analysing differences between algorithm configurations through ablation. Journal of Heuristics, 22(4):431–458, 2016.

See Also

plotAblation() ablation_cmdline()

Examples

# \donttest{
logfile <- system.file(package="irace", "exdata", "sann.rda")
# Execute ablation between the first and the best configuration found by irace.
ablog <- ablation(logfile, ablationLogFile = NULL)
plotAblation(ablog)
# Execute ablation between two selected configurations, and selecting only a
# subset of parameters, directly reading the setup from the irace log file.
ablog <- ablation(logfile, src = 1, target = 10,
                  ab_params = c("temp"), ablationLogFile = NULL)
plotAblation(ablog)
# }