recipes (version 0.1.0)

step_invlogit: Inverse Logit Transformation

Description

step_invlogit creates a specification of a recipe step that will transform the data from real values to be between zero and one.

Usage

step_invlogit(recipe, ..., role = NA, trained = FALSE, columns = NULL)

Arguments

recipe

A recipe object. The step will be added to the sequence of operations for this recipe.

...

One or more selector functions to choose which variables are affected by the step. See selections for more details.

role

Not used by this step since no new variables are created.

trained

A logical to indicate if the quantities for preprocessing have been estimated.

columns

A character string of variable names that will be (eventually) populated by the terms argument.

Value

An updated version of recipe with the new step added to the sequence of existing steps (if any).

Details

The inverse logit transformation takes values on the real line and translates them to be between zero and one using the function f(x) = 1/(1+exp(-x)).

See Also

step_logit step_log step_sqrt step_hyperbolic recipe prep.recipe bake.recipe

Examples

# NOT RUN {
data(biomass)

biomass_tr <- biomass[biomass$dataset == "Training",]
biomass_te <- biomass[biomass$dataset == "Testing",]

rec <- recipe(HHV ~ carbon + hydrogen + oxygen + nitrogen + sulfur,
              data = biomass_tr)

ilogit_trans <- rec  %>%
  step_center(carbon, hydrogen) %>%
  step_scale(carbon, hydrogen) %>%
  step_invlogit(carbon, hydrogen)

ilogit_obj <- prep(ilogit_trans, training = biomass_tr)

transformed_te <- bake(ilogit_obj, biomass_te)
plot(biomass_te$carbon, transformed_te$carbon)
# }