Shrinks a paradox::ParamSet towards a point. Boundaries of numeric values are shrinked to an interval around the point of half of the previous length, while for discrete variables, a random (currently not chosen) level is dropped.

Note that for paradox::ParamLgls the value to be shrinked around is set as
the `default`

value instead of dropping a level. Also, a tag `shrinked`

is
added.

Note that the returned paradox::ParamSet has lost all its original
`default`

s, as they may have become infeasible.

If the paradox::ParamSet has a trafo, `x`

is expected to contain the
transformed values.

## Arguments

- param_set
(paradox::ParamSet)

The paradox::ParamSet to be shrinked.- x
(data.table::data.table)

data.table::data.table with one row containing the point to shrink around.- check.feasible
(

`logical(1)`

)

Should feasibility of the parameters be checked? If feasibility is not checked, and invalid values are present, no shrinking will be done. Must be turned off in the case of the paradox::ParamSet having a trafo. Default is`FALSE`

.

## Examples

```
library(paradox)
library(data.table)
param_set = ParamSet$new(list(
ParamDbl$new("x1", lower = 0, upper = 10),
ParamInt$new("x2", lower = -10, upper = 10),
ParamFct$new("x3", levels = c("a", "b", "c")),
ParamLgl$new("x4"))
)
x = data.table(x1 = 5, x2 = 0, x3 = "b", x4 = FALSE)
shrink_ps(param_set, x = x)
#> <ParamSet>
#> id class lower upper nlevels default value
#> 1: x1 ParamDbl 2.5 7.5 Inf <NoDefault[3]>
#> 2: x2 ParamInt -5.0 5.0 11 <NoDefault[3]>
#> 3: x3 ParamFct NA NA 2 <NoDefault[3]>
#> 4: x4 ParamLgl NA NA 2 FALSE
```