Create Optimization Callback

Specialized mlr3misc::Callback for optimization. Callbacks allow to customize the behavior of processes in bbotk. The callback_optimization() function creates a CallbackOptimization. Predefined callbacks are stored in the dictionary mlr_callbacks and can be retrieved with clbk(). For more information on optimization callbacks see callback_optimization().

Super class

mlr3misc::Callback -> CallbackOptimization

Public fields

on_optimization_begin

(function())
Stage called at the beginning of the optimization. Called in Optimizer$optimize().

on_optimizer_before_eval

(function())
Stage called after the optimizer proposes points. Called in OptimInstance$eval_batch().

on_optimizer_after_eval

(function())
Stage called after points are evaluated. Called in OptimInstance$eval_batch().

on_result

(function())
Stage called after result are written. Called in OptimInstance$assign_result().

on_optimization_end

(function())
Stage called at the end of the optimization. Called in Optimizer$optimize().

Methods

Public methods

• CallbackOptimization$clone()

Inherited methods

• mlr3misc::Callback$call()
• mlr3misc::Callback$format()
• mlr3misc::Callback$help()
• mlr3misc::Callback$initialize()
• mlr3misc::Callback$print()

---

Method clone()

The objects of this class are cloneable with this method.

Usage

CallbackOptimization$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

Examples

# write archive to disk
callback_optimization("bbotk.backup",
  on_optimization_end = function(callback, context) {
    saveRDS(context$instance$archive, "archive.rds")
  }
)
#> <CallbackOptimization:bbotk.backup>
#> * Active Stages: on_optimization_end