(def *evett* [])

(defn n! [n]
  (if (or (= n 0) (= n 1)) 1 (* n (n! (- n 1)))))

(defn calculate-t [l j]
  (/ (* (Math/exp (- l)) (Math/pow l j)) (n! j)))

(let [p-values [0.25 0.22 0.14 0.14 0.069 0.064 0.033 0.033 0.022 0.02 0.013]
      s-values [0.728 0.166 0.065 0.018 0.018 0.006]]

(defn evett 
  ([lamb f-value n] (evett lamb f-value n 100))
  ([lamb f-value n lr-cap]
     (min lr-cap (+ (/ (* (first p-values) (calculate-t lamb (+ 1 n)))
		       (* (second p-values) (nth s-values n) f-value))
		    (calculate-t lamb 0))))))

(defn random-evett
  ([] (random-evett 1 1 10 0.01 0.25 1 5))
  ([samples] (random-evett samples 1 10 0.01 0.25 1 5))
  ([min-lamb max-lamb min-f-values max-f-values min-n max-n] 
     (random-evett 1 min-lamb max-lamb min-f-values max-f-values min-n max-n))
  ([samples min-lamb max-lamb min-f-values max-f-values min-n max-n] 
     (dotimes [one samples]
       (let [lamb (+ (rand max-lamb) min-lamb)
	     f-values (* min-f-values (+ (rand (* 100 max-f-values)) 1))
	     n (Math/round (rand max-n))
	     lr (evett lamb f-values n)
	     new-lr (if (>= lr 10) 10 0) ]
	 (def *evett* (conj *evett* [lamb f-values new-lr]))))
     (let [result *evett*]
       (def *evett* [])
         result)))