Scalor Base Class

Base class representing ranking operations, inheriting from MiesOperator.

A Scalor gets a table of individuals as input, along with information on the individuals' performance values and returns a vector of a possible scalarization of individuals' fitness (or other qualities).

Scalors can be used by Selectors as a basis to select individuals by. This way it is possible to have tournament selection (SelectorTournament) or elite selection (SelectorBest) based on different, configurable qualities of individuals.

Unlike most other operator types inheriting from MiesOperator, the $operate() function has two arguments, which are passed on to $.scale()

• values :: data.frame
  Individuals to operate on. Must pass the check of the Param given in the last $prime() call and may not have any missing components.

• fitnesses :: numeric | matrix
  Fitnesses for each individual given in values. If this is a numeric, then its length must be equal to the number of rows in values. If this is a matrix, if number of rows must be equal to the number of rows in values, and it must have one column when doing single-crit optimization and one column each for each "criterion" when doing multi-crit optimization.
  Note that fitness values are always maximized, both in single- and multi-criterion optimization, so objective output is multiplied with -1 if it is tagged as "minimize".

The return value of an operation should be a numeric vector with one finite value for each entry of values, assigning high values to individuals in some way more "desirable" than others with low values.

Inheriting

Scalor is an abstract base class and should be inherited from. Inheriting classes should implement the private $.scale() function. The user of the object calls $operate(), and the arguments are passed on to private $.scale() after checking that the operator is primed, that the values argument conforms to the primed domain and that other values match. Typically, the $initialize() function should also be overloaded, and optionally the $prime() function; they should call their super equivalents.

See also

Other base classes: Filtor, FiltorSurrogate, MiesOperator, Mutator, MutatorDiscrete, MutatorNumeric, OperatorCombination, Recombinator, RecombinatorPair, Selector, SelectorScalar

Other scalors: dict_scalors_aggregate, dict_scalors_domcount, dict_scalors_fixedprojection, dict_scalors_hypervolume, dict_scalors_nondom, dict_scalors_one, dict_scalors_proxy, dict_scalors_single

Super class

miesmuschel::MiesOperator -> Scalor

Active bindings

supported

(character)
Optimization supported by this Scalor, can be "single-crit", "multi-crit", or both.

Methods

Public methods

• Scalor$new()

• Scalor$clone()

Inherited methods

• miesmuschel::MiesOperator$help()
• miesmuschel::MiesOperator$operate()
• miesmuschel::MiesOperator$prime()
• miesmuschel::MiesOperator$print()
• miesmuschel::MiesOperator$repr()

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Method new()

Initialize base class components of the Mutator.

Usage

Scalor$new(
  param_classes = c("ParamLgl", "ParamInt", "ParamDbl", "ParamFct"),
  param_set = ps(),
  supported = c("single-crit", "multi-crit"),
  packages = character(0),
  dict_entry = NULL,
  own_param_set = quote(self$param_set)
)

Arguments

param_classes

(character)
Classes of parameters that the operator can handle. May contain any of "ParamLgl", "ParamInt", "ParamDbl", "ParamFct". Default is all of them.
The $param_classes field will reflect this value.

param_set

(ParamSet | list of expression)
Strategy parameters of the operator. This should be created by the subclass and given to super$initialize(). If this is a ParamSet, it is used as the MiesOperator's ParamSet directly. Otherwise it must be a list of expressions e.g. created by alist() that evaluate to ParamSets, possibly referencing self and private. These ParamSet are then combined using a ParamSetCollection. Default is the empty ParamSet.
The $param_set field will reflect this value.

supported

(character)
Subset of "single-crit" and "multi-crit", indicating wether single and / or multi-criterion optimization is supported. Default both of them.
The $supported field will reflect this value.

packages

(character) Packages that need to be loaded for the operator to function. This should be declared so these packages can be loaded when operators run on parallel instances. Default is character(0).
The $packages field will reflect this values.

dict_entry

(character(1) | NULL)
Key of the class inside the Dictionary (usually one of dict_mutators, dict_recombinators, dict_selectors), where it can be retrieved using a short access function. May be NULL if the operator is not entered in a dictionary.
The $dict_entry field will reflect this value.

own_param_set

(language)
An expression that evaluates to a ParamSet indicating the configuration parameters that are entirely owned by this operator class (and not proxied from a construction argument object). This should be quote(self$param_set) (the default) when the param_set argument is not a list of expressions.

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Method clone()

The objects of this class are cloneable with this method.

Usage

Scalor$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.