access_logs.R

# Copyright 2015- Takeshi Arabiki
# License: MIT License (http://opensource.org/licenses/MIT)
library(data.table)

access_logs <- (function() {

set.seed(0)

USER_COUNT <- 10000
PAGES <- c("page1", "page2", "page3")
STATES <- c("new", "normal", "active", "inactive")

INIT_PAGE_PROB <- structure(c(0.7, 0.2, 0.1), names = PAGES)
PAGE_TRANS_PROB <- matrix(c(
    0.1, 0.4, 0.5,
    0.8, 0.1, 0.1,
    0.8, 0.1, 0.1
), 3, byrow = TRUE, dimnames = list(PAGES, PAGES))

STATE_TRANS_PROB <- matrix(c(
    0.4, 0.2, 0.2, 0.2,
    0.0, 0.4, 0.2, 0.4,
    0.0, 0.1, 0.9, 0.0,
    0.0, 0.1, 0.0, 0.9
), 4, byrow = TRUE, dimnames = list(STATES, STATES))

page_interval_time <- function(page) {
    mean_interval <- switch(page, page1 = 30, 10)
    return(as.integer(rnbinom(1, 1, mu = mean_interval - 1) + 1))
}

session_interval_time <- function(state) {
    interval_days <- switch(
        state,
        new = sample(1:3, 1, prob = c(0.7, 0.2, 0.1)),
        normal = rpois(1, 2) + 1,
        active = sample(1:3, 1, prob = c(0.7, 0.2, 0.1)),
        inactive = sample(12, 1) * 30
    )
    return(as.integer(interval_days * 86400 + rnorm(1, 0, 3600)))
}

access_count_per_session <- function() {
    mean_access_count <- 3
    return(rpois(1, mean_access_count - 1) + 1)
}


HOUR_ACCESS_RATIO <- c(rep(0.1, 9), rep(1, 12), rep(0.1, 3))
BASE_TIME <- as.integer(as.POSIXct("2015-05-03"))
MAX_TIME <- as.integer(as.POSIXct("2015-06-06"))
MAX_USER_ID <- 999999999
BLOCK_SIZE <- 100000


user_ids <- sample(MAX_USER_ID, USER_COUNT)
hours <- sample(24, USER_COUNT, replace = TRUE, prob = HOUR_ACCESS_RATIO) - 1L
first_access_times <- BASE_TIME + hours * 3600L + sample(3600, USER_COUNT, replace = TRUE) - 1L
log_times <- integer(BLOCK_SIZE)
log_user_ids <- integer(BLOCK_SIZE)
log_pages <- character(BLOCK_SIZE)

current_row <- 0L
for (i in seq_along(user_ids)) {
    user_id <- user_ids[i]
    time <- first_access_times[i]
    state <- "new"
    repeat {
        page <- sample(PAGES, 1, prob = INIT_PAGE_PROB)
        access_count <- access_count_per_session()
        repeat {
            current_row <- current_row + 1L
            if (current_row > length(log_times)) {
                log_times <- c(log_times, integer(length(log_times)))
                log_user_ids <- c(log_user_ids, integer(length(log_user_ids)))
                log_pages <- c(log_pages, character(length(log_pages)))
            }
            log_times[current_row] <- time
            log_user_ids[current_row] <- user_id
            log_pages[current_row] <- page
            access_count <- access_count - 1
            if (access_count == 0) {
                break
            }
            time <- time + page_interval_time(page)
            page <- sample(PAGES, 1, prob = PAGE_TRANS_PROB[page, ])
        }
        state <- sample(STATES, 1, prob = STATE_TRANS_PROB[state, ])
        time <- time + session_interval_time(state)
        if (time >= MAX_TIME) {
            break
        }
    }
}

access_logs <- data.table(
    time = log_times[1:current_row],
    user_id = log_user_ids[1:current_row],
    page = log_pages[1:current_row]
)
access_logs[, c("idate", "itime") := IDateTime(as.POSIXlt(time, origin = "1970-01-01"))]

return(access_logs)

})()