GitHub - mlr-org/paradox: ParamHelpers Next Generation (original) (raw)

paradox

Package website: release | dev

Universal Parameter Space Description and Tools.

Installation

remotes::install_github("mlr-org/paradox")

Usage

Create a simple ParamSet using all supported Parameter Types:

• integer numbers ("int")
• real-valued numbers ("dbl")
• truth values TRUE or FALSE ("lgl")
• categorical values from a set of possible strings ("fct")
• further types are only possible by using transformations.

pset = ps( z = p_int(lower = 1, upper = 3), x = p_dbl(lower = -10, upper = 10), flag = p_lgl(), methods = p_fct(c("a","b","c")) )

Draw random samples / create random design:

generate_design_random(pset, 3) #> with 3 rows: #> z x flag methods #> 1: 1 7.660348 FALSE b #> 2: 3 8.809346 FALSE c #> 3: 2 -9.088870 FALSE b

Generate LHS Design:

requireNamespace("lhs") #> Loading required namespace: lhs generate_design_lhs(pset, 3) #> with 3 rows: #> z x flag methods #> 1: 1 -3.984673 TRUE b #> 2: 2 7.938035 FALSE a #> 3: 3 1.969783 TRUE c

Generate Grid Design:

generate_design_grid(pset, resolution = 2) #> with 24 rows: #> z x flag methods #> 1: 1 -10 TRUE a #> 2: 1 -10 TRUE b #> 3: 1 -10 TRUE c #> 4: 1 -10 FALSE a #> 5: 1 -10 FALSE b #> 6: 1 -10 FALSE c #> 7: 1 10 TRUE a #> [ reached getOption("max.print") -- omitted 18 rows ]

Properties of the parameters within the ParamSet:

pset$ids() #> [1] "z" "x" "flag" "methods" pset$levels #> $z #> NULL #> #> $x #> NULL #> #> $flag #> [1] TRUE FALSE #> #> $methods #> [1] "a" "b" "c" pset$nlevels #> z x flag methods #> 3 Inf 2 3 pset$is_number #> z x flag methods #> TRUE TRUE FALSE FALSE pset$lower #> z x flag methods #> 1 -10 NA NA pset$upper #> z x flag methods #> 3 10 NA NA

Parameter Checks

Check that a parameter satisfies all conditions of a ParamSet, using $test() (returns FALSE on mismatch), $check() (returns error description on mismatch), and $assert() (throws error on mismatch):

pset$test(list(z = 1, x = 1)) #> [1] TRUE pset$test(list(z = -1, x = 1)) #> [1] FALSE pset$check(list(z = -1, x = 1)) #> [1] "z: Element 1 is not >= 0.5" pset$assert(list(z = -1, x = 1)) #> Error in pset$assert(list(z = -1, x = 1)): Assertion on 'list(z = -1, x = 1)' failed: z: Element 1 is not >= 0.5.

Transformations

Transformations are functions with a fixed signature.

• x A named list of parameter values
• param_set the ParamSet used to create the design

Transformations can be used to change the distributions of sampled parameters. For example, to sample values between 2−32^-32−3 and 232^323 in a log_2log_2log_2-uniform distribution, one can sample uniformly between -3 and 3 and exponentiate the random value inside the transformation. Alternatively, logscale = TRUE can be set; in this case, lower and upper represent the values after the transformation.

pset = ps( z = p_int(lower = -3, upper = 3), x = p_dbl(lower = 2^-3, upper = 2^3, logscale = TRUE) ) pset$extra_trafo = function(x, param_set) { x$z = 2^x$z return(x) } pset_smplr = SamplerUnif$new(pset) x = pset_smplr$sample(2) xst = x$transpose() xst #> [[1]] #> [[1]]$z #> [1] 0.125 #> #> [[1]]$x #> [1] 0.6985067 #> #> #> [[2]] #> [[2]]$z #> [1] 0.5 #> #> [[2]]$x #> [1] 0.5795772

Further documentation can be found in the in-depth tutorial