R/step_scale.R

In jkennel/hydrorecipes: Hydrogeology steps

#^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
#
# Adjust the dispersion (e.g. scale by standard deviation) ---------------------
#
#^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
StepScale <- R6Class(
  classname = "step_scale",
  inherit = Step,
  public = list(
    column_values = c(),
    na_rm = NA,
    fun = NULL,
    n_sd = NA_integer_,

    # step specific variables
    initialize = function(terms,
                          na_rm = TRUE,
                          fun = collapse::fsd,
                          n_sd = 1L,
                          role = "predictor",
                          ...) {

      # get function parameters to pass to parent
      terms <- substitute(terms)
      env_list <- get_function_arguments()
      env_list$step_name <- "step_scale"
      env_list$type <- "modify"
      super$initialize(
        terms = terms,
        env_list[names(env_list) != "terms"],
        ...
      )

      self$na_rm <- na_rm
      self$fun <- fun
      self$n_sd <- n_sd

      invisible(self)
    },
    prep = function(data) {

      self$column_values <- self$fun(data, na.rm = self$na_rm) * (self$n_sd)
      self$column_values <- 1.0 / self$column_values
    },

    # subtract the central value from a column
    bake = function(s) {

      s[["result"]][self$columns] <- s[["result"]][self$columns] %r*% self$column_values

      return(NULL)

    }

  )
)