R/eliminate_strategy.R

In yukiyanai/rgamer: rgamer: Learn Game Theory Using R

#' @title Eliminate a strategy from a normal-form game.
#' @description \code{eliminate_strategy()} eliminates a strategy from a
#'     normal-form game defined by \code{normal_form()}.
#' @details This function eliminates a strategy from a normal-form game defined
#'     by \code{norma_form()}. For instance, you can remove a dominated
#'     strategy found by \code{dom()}.
#' @return A normal-form game object with the specified strategies eliminated.
#' @param game A normal-form game object created by \code{normal_form()}.
#' @param player A player one of whose strategies will be eliminated.
#' @param eliminated A strategy to be eliminated. Case sensitive.
#' @author Yoshio Kamijo and Yuki Yanai <yanai.yuki@@kochi-tech.ac.jp>
#' @export
eliminate_strategy <- function(game,
                               player,
                               eliminated) {

  s1 <- s2 <- NULL

  elim_pos <- which(game$player == player)

  for (i in 1:length(game$strategy)) {
    if (i == elim_pos) {
      game$strategy[[i]] <- game$strategy[[i]][game$strategy[[i]] != eliminated]
    }
  }

  new_df <- game$df |>
    dplyr::filter(s1 %in% game$strategy$s1,
                  s2 %in% game$strategy$s2)

  normal_form(players = game$player,
              s1 = game$strategy$s1,
              s2 = game$strategy$s2,
              payoffs1 = new_df$payoff1,
              payoffs2 = new_df$payoff2)
}