Param: Create a description object for a parameter.

Description

For each parameter type a special constructor function is available, see below.

The S3 class is a list which stores these elements:

id [character(1)]: See argument of same name.

type [character(1)]

Data type of parameter. Possible types are “numeric”, “numericvector”, “integer”, “integervector”, “logical”, “logicalvector”, “discrete”, “discretevector”, “function”, “untyped”.

len [integer(1)]

See argument of same name.

lower [numeric]

See argument of same name. Length of this vector is len.

upper [numeric]

See argument of same name. Length of this vector is len.

values [list]

Discrete values, always stored as a named list.

trafo [NULL | function(x)]

See argument of same name.

requires [NULL | expression]

See argument of same name.

Usage

makeNumericParam(id, lower = -Inf, upper = Inf, allow.inf = FALSE, default, trafo = NULL, requires = NULL, tunable = TRUE)
makeNumericVectorParam(id, len, lower = -Inf, upper = Inf, allow.inf = FALSE, cnames = NULL, default, trafo = NULL, requires = NULL, tunable = TRUE)
makeIntegerParam(id, lower = -Inf, upper = Inf, default, trafo = NULL, requires = NULL, tunable = TRUE)
makeIntegerVectorParam(id, len, lower = -Inf, upper = Inf, cnames = NULL, default, trafo = NULL, requires = NULL, tunable = TRUE)
makeLogicalParam(id, default, requires = NULL, tunable = TRUE)
makeLogicalVectorParam(id, len, cnames = NULL, default, requires = NULL, tunable = TRUE)
makeDiscreteParam(id, values, trafo = NULL, default, requires = NULL, tunable = TRUE)
makeDiscreteVectorParam(id, len, values, default, requires = NULL, tunable = TRUE)
makeFunctionParam(id, default = default, requires = NULL)
makeUntypedParam(id, default, requires = NULL, tunable = TRUE)
makeCharacterParam(id, default, requires = NULL)
makeCharacterVectorParam(id, len, cnames = NULL, default, requires = NULL)

Arguments

[character(1)] Name of parameter.

lower

[numeric] Lower bounds. A singe value of length 1 is automatically replicated to len for vector parameters. Default is -Inf.

upper

[numeric] Upper bounds. A singe value of length 1 is automatically replicated to len for vector parameters. Default is Inf.

allow.inf

[logical(1)] Allow infinite values for numeric and numericvector params to be feasible settings. Default is FALSE.

default

[any] Default value used in learner. If this argument is missing, it means no default value is available.

trafo

[NULL | function(x)] Function to transform parameter. It should be applied to the parameter value before it is, e.g., passed to a corresponding objective function. Function must accept a parameter value as the first argument and return a transformed one. Default is NULL which means no transformation.

requires

[NULL | call | expression] States requirements on other parameters' values, so that setting this parameter only makes sense if its requirements are satisfied (dependent parameter). Can be an object created either with expression or quote, the former type is auto-converted into the later. Only really useful if the parameter is included in a ParamSet. Note that if your dependent parameter is a logical Boolean you need to verbosely write requires = quote(a == TRUE) and not requires = quote(a). Default is NULL which means no requirements.

tunable

[logical(1)] Is this parameter tunable? Defining a parameter to be not-tunable allows to mark arguments like, e.g., “verbose” or other purely technical stuff, and allows them to be excluded from later automatic optimization procedures that would try to consider all available parameters. Default is TRUE (except for untyped, function, character and characterVector) which means it is tunable.

len

[integer(1)] Length of vector parameter.

cnames

[character] Component names for vector params (except discrete). Every function in this package that creates vector values for such a param, will name that vector with cnames.

values

[vector | list] Possible discrete values. Instead of using a vector of atomic values, you are also allowed to pass a list of quite “complex” R objects, which are used as discrete choices. If you do the latter, the elements must be uniquely named, so that the names can be used as internal representations for the choice.

Value

[Param].

Examples

Run this code

makeNumericParam("x",lower = -1, upper = 1)
makeNumericVectorParam("x", len = 2)
makeDiscreteParam("y", values = c("a","b"))
makeCharacterParam("z")

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