ablation {irace}

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"),
  n_instances = 1L,
  seed = 1234567,
  ablationLogFile = "log-ablation.Rdata",
  ...
)

Arguments

iraceResults

(list()|character(1)) iraceResults 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

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.

ab.params

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

type

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.

n_instances

(integer(1)) Number of instances used in "full" ablation will be n_instances * scenario$firstTest.

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.

...

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

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.

Author(s)

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()

Examples

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)