dates-normal-destribution.clj

dates-normal-destribution.clj

(ns dates-normal-distribution
  (:import [java.util.concurrent ThreadLocalRandom]
           [java.time LocalDate]))

(defn next-gaussian
  []
  (let [k 0.166
        r (.nextGaussian (ThreadLocalRandom/current))
        x (+ 0.5 (* r k))]
    (if (<= 0 x 1)
      x
      (recur))))

(defn get-random-date
  []
  (let [d (+ (* 90 365 (next-gaussian)) 3650)
        n (LocalDate/now)]
    (.minusDays n d)))

(defn get-random-table
  [n]
  (loop [acc {}
         n n]
    (if (zero? n)
      (sort-by first acc)
      (let [x (get-random-date)
            y (.getYear x)]
        (recur (update acc y (fnil inc 0))
               (dec n))))))

(comment

  (clojure.pprint/pprint (get-random-table 80000000))
  (get-random-date)

  )