bbotk (version 0.3.1)

ArchiveBest: Minimal logging object for objective function evaluations

Description

The ArchiveBest stores no data but records the best scoring evaluation passed to $add_evals(). The Archive API is fully implemented but many parameters are ignored and some methods do nothing. The archive still works with TerminatorClockTime, TerminatorEvals, TerminatorNone and TerminatorEvals.

Super class

bbotk::Archive -> ArchiveBest

Active bindings

n_evals

(integer(1)) Number of evaluations stored in the archive.

n_batch

(integer(1)) Number of batches stored in the archive.

Methods

Public methods

• ArchiveBest$new()

• ArchiveBest$add_evals()

• ArchiveBest$best()

• ArchiveBest$clone()

• bbotk::Archive$clear()

• bbotk::Archive$format()

• bbotk::Archive$print()

Method new()

Creates a new instance of this R6 class.

Usage

ArchiveBest$new(
  search_space,
  codomain,
  check_values = FALSE,
  store_x_domain = FALSE
)

Arguments

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.

codomain

(paradox::ParamSet) Specifies codomain of function. Most importantly the tags of each output "Parameter" define whether it should be minimized or maximized. The default is to minimize each component.

check_values

(logical(1)) ignored.

store_x_domain

(logical(1)) Determines if x values, should be stored in $data$x_domain as list items. The trafo will be applied if defined in search_space.

Method add_evals()

Stores the best result in ydt.

Usage

ArchiveBest$add_evals(xdt, xss_trafoed = NULL, ydt)

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.

xss_trafoed

(list()) Transformed point(s) in the domain space.

ydt

(data.table::data.table()) Optimal outcome.

Method best()

Returns the best scoring evaluation. For single-crit optimization, the solution that minimizes / maximizes the objective function. For multi-crit optimization, the Pareto set / front.

Usage

ArchiveBest$best(m = NULL)

Arguments

m

(integer()) ignored.

Returns

data.table::data.table()

Method clone()

The objects of this class are cloneable with this method.

Usage

ArchiveBest$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.