ps: Construct a ParamSet using Short Forms

In mlr-org/phng: Define and Work with Parameter Spaces for Complex Algorithms

Construct a ParamSet using Short Forms

Description

The ps() short form constructor uses Domain objects (p_dbl, p_fct, ...) to construct ParamSets in a succinct and readable way.

For more specifics also see the documentation of Domain.

Usage

ps(
  ...,
  .extra_trafo = NULL,
  .constraint = NULL,
  .allow_dangling_dependencies = FALSE
)

Arguments

...	(Domain) Named arguments of Domain objects. The ParamSet will be constructed of the given Domains, The names of the arguments will be used as ⁠$id()⁠ in the resulting ParamSet.
.extra_trafo	(⁠function(x, param_set)⁠) Transformation to set the resulting ParamSet's ⁠$trafo⁠ value to. This is in addition to any trafo of Domain objects given in ..., and will be run after transformations of individual parameters were performed.
.constraint	(⁠function(x)⁠) Constraint function. When given, this function must evaluate a named list() of values and determine whether it satisfies constraints, returning a scalar logical(1) value.
.allow_dangling_dependencies	(logical) Whether dependencies depending on parameters that are not present should be allowed. A parameter x having depends = y == 0 if y is not present in the ps() call would usually throw an error, but if dangling dependencies are allowed, the dependency is added regardless. This is usually a bad idea and mainly for internal use. Dependencies between ParamSets when using to_tune() can be realized using this.

Value

A ParamSet object.

See Also

Other ParamSet construction helpers: Domain(), to_tune()

Examples

pars = ps(
  a = p_int(0, 10),
  b = p_int(upper = 20),
  c = p_dbl(),
  e = p_fct(letters[1:3]),
  f = p_uty(custom_check = checkmate::check_function)
)
print(pars)

pars = ps(
  a = p_dbl(0, 1, trafo = exp),
  b = p_dbl(0, 1, trafo = exp),
  .extra_trafo = function(x, ps) {
    x$c <- x$a + x$b
    x
  }
)

# See how the addition happens after exp()ing:
pars$trafo(list(a = 0, b = 0))

pars$values = list(
  a = to_tune(ps(x = p_int(0, 1),
    .extra_trafo = function(x, param_set) list(a = x$x)
  )),
  # make 'y' depend on 'x', but they are defined in different ParamSets
  # Therefore we need to allow dangling dependencies here.
  b = to_tune(ps(y = p_int(0, 1, depends = x == 1),
    .extra_trafo = function(x, param_set) list(b = x$y),
    .allow_dangling_dependencies = TRUE
  ))
)

pars$search_space()

mlr-org/phng documentation built on April 22, 2024, 4:34 p.m.