R/predecessors.to.edges.R

In antoanne/ifmFramework: Financial evaluation of Projects

#' Generate a vector with the edges to be plotted by draw.graph function.
#'
#' @name predecessors.to.edges
#'
#' @aliases predecessors_to_edges predecessorsToEdges
#'
#' @param list.of.predecessors The vector that contain all activities predecessors.
#'
#' @return edges - List of edges to be used on the draw.graph function.
#'
#' @export predecessors.to.edges
#'
#' @description This function is responsible for reading a vector with all
#' activities predecessors and generate a list of the edges that will be
#' plotted by the draw.graph function.
#'
#' @keywords draw draw.graph
#'
#' @family utility
#'
#' @examples
#'
#' data("ex.sheet.data")
#' ex.edges <- predecessors.to.edges(ex.sheet.data$predecessors)
#'
predecessors.to.edges <- predecessors_to_edges <- predecessorsToEdges <-

  # initialize a vector of predecessors if NULL
  function(list.of.predecessors = list()){

    # initialize a vector with the edges
    edges <- c()

    # counter with activity index
    activity.index <- 1

    # loop in the list.of.predecessors
    for (predecessors in list.of.predecessors) {

      # loop the predecessors if there are more then one activity predecessor
      for (item in predecessors) {
        # discard the item 0 (start of the graph)
        if(strtoi(item) != 0){
          # include the pair item and activity index
          edges <- c(edges, strtoi(item), activity.index);
        }
      }
      # increment the activity index
      activity.index <- activity.index + 1;
    }

    return (edges)
  }