R/is_intralayer_interaction.R

In tylermorganwall/skpr: Design of Experiments Suite: Generate and Evaluate Optimal Designs

#'@title Layer Interaction
#'
#'@description Determines if a factor is a intra-layer interaction
#'
#'@param design The design matrix
#'@param model The model
#'@param split_layers The layer of split plots for each main effect term
#'@return List of booleans for each subplot strata layer
#'@keywords internal
#'
is_intralayer_interaction = function(design, model, split_layers) {
  model = as.formula(paste0(
    "~",
    paste(attr(terms.formula(model), "term.labels"), collapse = " + ")
  ))
  splitterms = unlist(strsplit(
    as.character(model)[-1],
    split = " + ",
    fixed = TRUE
  ))
  ismaineffect = rep(FALSE, length(splitterms))
  ismaineffect[1:length(split_layers)] = TRUE
  interactions = list()
  if (max(split_layers) > 0) {
    for (i in 1:max(split_layers, na.rm = TRUE)) {
      wholeplotterms = colnames(design)[split_layers == i]
      higherplotterms = colnames(design)[split_layers > i]
      wholeorwholeinteraction = rep(FALSE, length(splitterms))
      higherplotinteraction = rep(FALSE, length(splitterms))

      for (term in wholeplotterms) {
        regex = paste0(
          "(\\b",
          term,
          "\\b)|(\\b",
          term,
          ":)|(:",
          term,
          "\\b)|(\\b",
          term,
          "\\s\\*)|(\\*\\s",
          term,
          "\\b)"
        )
        wholeorwholeinteraction = wholeorwholeinteraction |
          grepl(regex, splitterms, perl = TRUE)
      }
      for (term in higherplotterms) {
        regex = paste0(
          "(\\b",
          term,
          "\\b)|(\\b",
          term,
          ":)|(:",
          term,
          "\\b)|(\\b",
          term,
          "\\s\\*)|(\\*\\s",
          term,
          "\\b)"
        )
        higherplotinteraction = higherplotinteraction |
          grepl(regex, splitterms, perl = TRUE)
      }
      interactions[[i]] = wholeorwholeinteraction &
        !ismaineffect &
        !higherplotinteraction
    }
  } else {
    for (i in seq_along(1:max(split_layers, na.rm = TRUE))) {
      interactions[[i]] = FALSE
    }
  }
  interactions
}