Post-selection race — psRace • irace

psRace performs a post-selection race of a set of configurations.

Usage

psRace(
  iraceResults,
  max_experiments,
  conf_ids = NULL,
  iteration_elites = FALSE,
  psrace_logFile = NULL
)

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.
max_experiments: numeric(1)
Number of experiments for the post-selection race. If it is equal to or smaller than 1, then it is a fraction of the total budget given by iraceResults$scenario$maxExperiments or iraceResults$scenario$maxTime / iraceResults$state$boundEstimate.
conf_ids: IDs of the configurations in iraceResults$allConfigurations to be used for the post-selection. If NULL, then the configurations are automatically selected.
iteration_elites: If FALSE, give priority to selecting the configurations that were elite in the last iteration. If TRUE, select from all elite configurations of all iterations. This parameter only has an effect when conf_ids is not NULL.
psrace_logFile: character(1)
Log file to save the post-selection race log. If NULL, the log is saved in iraceResults$scenario$logFile.

Value

The elite configurations after the post-selection. In addition, if iraceResults$scenario$logFile is defined, it saves an updated copy of iraceResults in that file, where iraceResults$psrace_log is a list with the following elements:

configurations: Configurations used in the post-selection race.
instances: Data frame with the instances used in the post-selection race. First column has the instances IDs from iraceResults$scenario$instances, second column the seed assigned to the instance.
max_experiments: Configuration budget assigned to the post-selection race.
experiments: Matrix of results generated by the post-selection race, in the same format as the matrix iraceResults$experiments. Column names are the configuration IDs and row names are the instance IDs.
elites: Best configurations found in the experiments.

Author

Leslie Pérez Cáceres and Manuel López-Ibáñez

Examples

# \donttest{
  irace_log <- read_logfile(system.file(package="irace", "exdata", "sann.rda"))
  # Use a temporary file to not change the original "sann.rda".
  psrace_logFile <- withr::local_tempfile(fileext = ".Rdata")
  # Execute the post-selection after the execution of irace. Use 10% of the total budget.
  psRace(irace_log, max_experiments=0.1, psrace_logFile = psrace_logFile)
#> # 2025-10-17 19:25:19 UTC: Starting post-selection:
#> # scenario maxExperiments:1000
#> # Configurations selected: 128, 80, 91, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13.
#> # Pending instances: 1, 1, 1, 6, 6, 4, 4, 6, 4, 4, 4, 6, 4, 4, 6, 4.
#> # 2025-10-17 19:25:19 UTC: seed: 687264462
#> # Configurations: 16
#> # Available experiments: 100
#> # minSurvival: 1
#> # Markers:
#>      x No test is performed.
#>      c Configurations are discarded only due to capping.
#>      - The test is performed and some configurations are discarded.
#>      = The test is performed but no configuration is discarded.
#>      ! The test is performed and configurations could be discarded but elite configurations are preserved.
#>      . Alive configurations were already evaluated on this instance and nothing is discarded.
#>      : All alive configurations are elite, but some need to be evaluated on this instance.
#> 
#> +-+-----------+-----------+-----------+----------------+-----------+--------+-----+----+------+
#> | |   Instance|      Alive|       Best|       Mean best| Exp so far|  W time|  rho|KenW|  Qvar|
#> +-+-----------+-----------+-----------+----------------+-----------+--------+-----+----+------+
#> |.|          1|         16|        128|   0.01996442284|          0|00:00:00|   NA|  NA|    NA|
#> |x|         10|         16|         91|   0.04671217104|         13|00:00:00|+0.19|0.59|0.8420|
#> |x|          9|         16|         91|   0.03917574490|         26|00:00:00|+0.31|0.54|0.6617|
#> |x|          8|         16|         91|   0.03487616768|         39|00:00:00|+0.37|0.53|0.5788|
#> |x|          6|         16|        128|    0.4500345539|         44|00:00:00|+0.32|0.46|0.5504|
#> |x|          7|         16|        128|    0.3975991523|         49|00:00:00|+0.26|0.38|0.6140|
#> |.|          4|         16|        128|     1.762868241|         49|00:00:00|+0.21|0.32|0.6903|
#> |.|          3|         16|        128|     2.045212556|         49|00:00:00|+0.23|0.33|0.6596|
#> |.|          2|         16|        128|     1.820441720|         49|00:00:00|+0.24|0.33|0.6561|
#> |.|          5|         16|        128|     1.649445285|         49|00:00:00|+0.25|0.32|0.6605|
#> |-|         11|          4|         80|    0.4915594776|         65|00:00:00|-0.03|0.07|0.7859|
#> |=|         12|          4|         91|    0.4379356217|         69|00:00:00|+0.01|0.09|0.7705|
#> |=|         13|          4|         91|    0.4057438824|         73|00:00:00|+0.05|0.12|0.7418|
#> |=|         14|          4|         91|    0.4014988437|         77|00:00:00|+0.08|0.15|0.7158|
#> |=|         15|          4|         91|    0.3874512014|         81|00:00:00|+0.10|0.16|0.6867|
#> |=|         16|          4|         91|    0.3677075297|         85|00:00:00|+0.05|0.11|0.7208|
#> |=|         17|          4|         91|    0.3538188571|         89|00:00:00|+0.06|0.11|0.7281|
#> |=|         18|          4|         91|    0.3518531743|         93|00:00:00|+0.07|0.12|0.7260|
#> |-|         19|          3|         91|    0.3379661034|         97|00:00:00|-0.02|0.04|0.6767|
#> |=|         20|          3|         91|    0.3256171422|        100|00:00:00|-0.00|0.05|0.6626|
#> +-+-----------+-----------+-----------+----------------+-----------+--------+-----+----+------+
#> Best-so-far configuration:          91    mean value:     0.3256171422
#> Description of the best-so-far configuration:
#>    .ID. tmax    temp .PARENT.
#> 91   91   66 44.6677       28
#> 
#> # 2025-10-17 19:25:21 UTC: Elite configurations (first number is the configuration ID; listed from best to worst according to the sum of ranks):
#>     tmax    temp
#> 91    66 44.6677
#> 80   123 42.5337
#> 128  191 40.5608
#> # Total CPU user time: 54.592, CPU sys time: 0.121, Wall-clock time: 55.109
#>     .ID. tmax    temp .PARENT. .RANK.  .WEIGHT.
#> 91    91   66 44.6677       28     37 0.5000000
#> 80    80  123 42.5337       18     38 0.3333333
#> 128  128  191 40.5608       80     45 0.1666667
  # Print psrace_log
  irace_log <- read_logfile(psrace_logFile)
  str(irace_log$psrace_log)
#> List of 5
#>  $ configurations :'data.frame':	3 obs. of  6 variables:
#>   ..$ .ID.    : int [1:3] 91 80 128
#>   ..$ tmax    : int [1:3] 66 123 191
#>   ..$ temp    : num [1:3] 44.7 42.5 40.6
#>   ..$ .PARENT.: int [1:3] 28 18 80
#>   ..$ .RANK.  : num [1:3] 37 38 45
#>   ..$ .WEIGHT.: num [1:3] 0.5 0.333 0.167
#>  $ instances      :Classes ‘data.table’ and 'data.frame':	20 obs. of  2 variables:
#>   ..$ instanceID: int [1:20] 20 19 7 25 34 50 42 6 21 10 ...
#>   ..$ seed      : int [1:20] 232049485 32055254 1641632623 1631511891 2050085845 822857599 188021279 1591959540 324610117 1741880949 ...
#>   ..- attr(*, ".internal.selfref")=<externalptr> 
#>  $ max_experiments: int 100
#>  $ experiments    : num [1:20, 1:16] 4.08 7.41 3.03 2.15 0.12 ...
#>   ..- attr(*, "dimnames")=List of 2
#>   .. ..$ : chr [1:20] "1" "10" "9" "8" ...
#>   .. ..$ : chr [1:16] "1" "2" "3" "4" ...
#>  $ elites         : int [1:3] 91 80 128
# }