OptimInstanceSingleCrit {bbotk}

Optimization Instance with budget and archive

Description

Wraps a single-criteria Objective function with extra services for convenient evaluation. Inherits from OptimInstance.

• Automatic storing of results in an Archive after evaluation.

• Automatic checking for termination. Evaluations of design points are performed in batches. Before a batch is evaluated, the Terminator is queried for the remaining budget. If the available budget is exhausted, an exception is raised, and no further evaluations can be performed from this point on.

Super class

bbotk::OptimInstance -> OptimInstanceSingleCrit

Methods

Public methods

• OptimInstanceSingleCrit$new()

• OptimInstanceSingleCrit$assign_result()

• OptimInstanceSingleCrit$clone()

Inherited methods

• bbotk::OptimInstance$clear()
• bbotk::OptimInstance$eval_batch()
• bbotk::OptimInstance$format()
• bbotk::OptimInstance$objective_function()
• bbotk::OptimInstance$print()

Method new()

Creates a new instance of this R6 class.

Usage

OptimInstanceSingleCrit$new(
  objective,
  search_space = NULL,
  terminator,
  keep_evals = "all",
  check_values = TRUE,
  callbacks = list()
)

Arguments

objective

(Objective).

search_space

(paradox::ParamSet)
Specifies the search space for the Optimizer. The paradox::ParamSet describes either a subset of the domain of the Objective or it describes a set of parameters together with a trafo function that transforms values from the search space to values of the domain. Depending on the context, this value defaults to the domain of the objective.

terminator

(Terminator).

keep_evals

(character(1))
Keep all or only best evaluations in archive?

check_values

(logical(1))
Should x-values that are added to the archive be checked for validity? Search space that is logged into archive.

callbacks

(list of mlr3misc::Callback)
List of callbacks.

Method assign_result()

The Optimizer object writes the best found point and estimated performance value here. For internal use.

Usage

OptimInstanceSingleCrit$assign_result(xdt, y)

Arguments

xdt

(data.table::data.table())
Set of untransformed points / points from the search space. One point per row, e.g. data.table(x1 = c(1, 3), x2 = c(2, 4)). Column names have to match ids of the search_space. However, xdt can contain additional columns.

y

(numeric(1))
Optimal outcome.

Method clone()

The objects of this class are cloneable with this method.

Usage

OptimInstanceSingleCrit$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.