小编bsl*_*ski的帖子

我在Clojure中总结了一长串比率,例如:

(defn sum-ratios
  [n]
  (reduce
    (fn [total ind]
      (+
        total
        (/
          (inc (rand-int 100))
          (inc (rand-int 100)))))
    (range 0 n)))

各种n的运行时间是:

• n = 10 ^ 4 ...... 41 ms
• n = 10 ^ 6 ...... 3.4 s
• n = 10 ^ 7 ...... 36秒

(不太精确)替代方案是将这些值加总为双精度:

(defn sum-doubles
  [n]
  (reduce
    (fn [total ind]
      (+
        total
        (double
          (/
            (inc (rand-int 100))
            (inc (rand-int 100))))))
    (range 0 n)))

此版本的运行时为:

• n = 10 ^ 4 ...... 8.8 ms
• n = 10 ^ 6 ...... …