R/filter_activity_frequency.R

In gertjanssenswillen/edeaR: Exploratory and Descriptive Event-Based Data Analysis

#' Filter: Activity frequency
#'
#' Filters the log based on frequency of activities.
#'
#'
#' Filtering the event log based in activity frequency can be done in two ways: using an interval of allowed frequencies, or specify a coverage percentage.
#'
#' \itemize{
#'
#' \item percentage: When filtering using a percentage p\%, the filter will return p% of the activity instances, starting from the activity labels with the highest
#' frequency. The filter will retain additional activity labels as long as the number of activity instances does not exceed the percentage threshold.
#'
#' \item interval: When filtering using an interval, activity labels will be retained when their absolute frequency fall in this interval. The interval is specified using
#' a numeric vector of length 2. Half open intervals can be created by using NA. E.g., `c(10, NA)` will select activity labels which occur 10 times or more.
#' }
#'
#' @param percentage The target coverage of activity instances. A percentile of 0.9 will return the most common activity types of the eventlog,
#' which account for at least 90\% of the activity instances.
#'
#' @param interval An activity frequency interval (numeric vector of length 2). Half open interval can be created using NA.
#'
#' @export filter_activity_frequency
#'
#' @inherit filter_activity params references seealso return

filter_activity_frequency <- function(eventlog, interval, percentage, reverse, ...) {
	UseMethod("filter_activity_frequency")
}

#' @describeIn filter_activity_frequency Filter eventlog on activity frequency
#' @export

filter_activity_frequency.eventlog <- function(eventlog,
											   interval = NULL,
											   percentage = NULL,
											   reverse = FALSE,
											   ...) {

	percentage <- deprecated_perc(percentage, ...)
	stopifnot(is.logical(reverse))
	if(!is.null(interval) && !is.null(percentage)) {
		stop("Provide interval OR percentage Cannot filter using both methods.")
	} else if(!is.null(interval)) {
		stopifnot(is.numeric(interval))
		if(length(interval) != 2 || any(interval < 0, na.rm = T) || all(is.na(interval))){
			stop("Interval should be a positive numeric vector of length 2. One of the elements can be NA to create open intervals.")
		} else {
			filter_activity_interval(eventlog, interval[1], interval[2], reverse)
		}
	} else if(!is.null(percentage)) {
		stopifnot(is.numeric(percentage))
		if(length(percentage) != 1 || percentage > 1 || percentage < 0) {
			stop("percentage should be a numeric vector of length 1 with a value between 0 and 1")
		} else{
			filter_activity_percentage(eventlog, percentage, reverse)
		}
	} else {
		stop("No filter arguments were provided. Please provide percentage or interval.")
	}
}

filter_activity_interval <- function(eventlog, lower, upper, reverse) {
	absolute_frequency <- NULL
	lower <- ifelse(is.na(lower), -Inf, lower)
	upper <- ifelse(is.na(upper), Inf, upper)

	activities(eventlog) %>%
		filter(between(absolute_frequency, lower, upper)) %>%
		pull(1) -> event_selection

	filter_activity(eventlog, event_selection, reverse)
}


filter_activity_percentage <- function(eventlog, percentage, reverse) {
	absolute_frequency <- NULL
	relative_frequency <- NULL
	r <- NULL

	act_freq <- activities(eventlog) %>%
		arrange(-absolute_frequency) %>%
		mutate(r = cumsum(relative_frequency)) %>%
		filter(dplyr::lag(r, default = 0) < percentage) %>%
		dplyr::pull(1) -> event_selection

	filter_activity(eventlog, event_selection, reverse)

}



#' @describeIn filter_activity_frequency Stratified filter for grouped eventlog
#' @export
#'
filter_activity_frequency.grouped_eventlog <- function(eventlog, interval = NULL, percentage = NULL, reverse = FALSE, ...) {
	grouped_filter(eventlog, filter_activity_frequency, interval, percentage, reverse, ...)
}

#' @rdname filter_activity_frequency
#' @export ifilter_activity_frequency
ifilter_activity_frequency <- function(eventlog) {

	ui <- miniPage(
		gadgetTitleBar("Filter activities based on frequency"),
		miniContentPanel(
			fillCol(flex = c(2,1),
					fillRow(flex = c(10,1,8),
							radioButtons("filter_type", "Filter type:", choices = c("Interval" = "int", "Use percentile cutoff" = "percentile")),
							" ",
							radioButtons("reverse", "Reverse filter: ", choices = c("Yes","No"), selected = "No")
					),
					uiOutput("filter_ui")

			)
		)
	)

	server <- function(input, output, session){

		output$filter_ui <- renderUI({
			absolute_frequency <- NULL
			if(input$filter_type == "int") {
				sliderInput("interval_slider", "Process time interval",
							min = 0, max = max(eventlog %>% activities() %>% pull(absolute_frequency)), value = c(0,1))

			}
			else if(input$filter_type == "percentile") {
				sliderInput("percentile_slider", "Percentage", min = 0, max = 100, value = 80)
			}
		})

		observeEvent(input$done, {

			if(input$filter_type == "int")
				filtered_log <- filter_activity_frequency(eventlog,
														  interval =  input$interval_slider,
														  reverse = ifelse(input$reverse == "Yes", TRUE, FALSE))
			else if(input$filter_type == "percentile") {
				filtered_log <- filter_activity_frequency(eventlog,
														  percentage = input$percentile_slider/100,
														  reverse = ifelse(input$reverse == "Yes", TRUE, FALSE))
			}

			stopApp(filtered_log)
		})
	}
	runGadget(ui, server, viewer = dialogViewer("Filter activities based on frequency", height = 400))

}