Set eta parameter for hyperband inside autotuner

[MislavSag]

How can I set eta parameter inside autoruner ?

at_ranger = auto_tuner(
  method = "hyperband",
  learner = graph_learner,
  resampling = rsmp("cv", folds = 3),
  measure = msr("classif.ce"),
  search_space = search_space
)

method accepts only character, but I would like to pass tuner tnr("hyperband", eta = 5)

[be-marc]

at_ranger = auto_tuner(
  method = "hyperband",
  learner = graph_learner,
  resampling = rsmp("cv", folds = 3),
  measure = msr("classif.ce"),
  search_space = search_space,
  eta = 3
)

Additional arguments ... are passed to the tuner.

[MislavSag]

Thanks for fast answer.

If ,for example, bidget parameter goes from 100 to 1000, how can I set to try every 100 values ? I thought eta parameter do this.

[be-marc]

The budget increases exponentially not linearly. You can check the schedule with different lower and upper bounds for the budget parameter and eta values.

mlr3hyperband::hyperband_schedule(r_min = 1, r_max = 81, eta = 3)

#>     bracket stage budget  n
#>  1:       4     0      1 81
#>  2:       4     1      3 27
#>  3:       4     2      9  9
#>  4:       4     3     27  3
#>  5:       4     4     81  1
#>  6:       3     0      3 34
#>  7:       3     1      9 11
#>  8:       3     2     27  3
#>  9:       3     3     81  1
#> 10:       2     0      9 15
#> 11:       2     1     27  5
#> 12:       2     2     81  1
#> 13:       1     0     27  8
#> 14:       1     1     81  2
#> 15:       0     0     81  5

[MislavSag]

Thanks!