Data commit

Task/Average-loop-length/Clojure/average-loop-length.clj

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+(ns cyclelengths
+  (:gen-class))
+
+(defn factorial [n]
+  " n! "
+  (apply *' (range 1 (inc n))))             ; Use *' (vs. *) to allow arbitrary length arithmetic
+
+(defn pow [n i]
+  " n^i"
+  (apply *' (repeat i n)))
+
+(defn analytical [n]
+  " Analytical Computation "
+  (->>(range 1 (inc n))
+      (map #(/ (factorial n) (pow n %) (factorial (- n %)))) ;calc n %))
+      (reduce + 0)))
+
+;; Number of random times to test each n
+(def TIMES 1000000)
+
+(defn single-test-cycle-length [n]
+  " Single random test of cycle length "
+  (loop [count 0
+         bits 0
+         x 1]
+    (if (zero? (bit-and x bits))
+      (recur (inc count) (bit-or bits x) (bit-shift-left 1 (rand-int n)))
+        count)))
+
+(defn avg-cycle-length [n times]
+  " Average results of single tests of cycle lengths "
+  (/
+   (reduce +
+           (for [i (range times)]
+             (single-test-cycle-length n)))
+  times))
+
+;; Show Results
+(println "\tAvg\t\tExp\t\tDiff")
+(doseq [q (range 1 21)
+        :let [anal (double (analytical q))
+              avg (double (avg-cycle-length q TIMES))
+              diff (Math/abs (* 100 (- 1 (/ avg anal))))]]
+  (println (format "%3d\t%.4f\t%.4f\t%.2f%%" q avg anal diff)))