scala – 为什么这个Clojure程序在一个可变数组上工作这么慢？

我试图在Clojure和Scala中解决this问题. Scala程序运行正常,并在我的Macbook Air上几秒钟内完成.然而,Clojure版本需要更长的时间.这里有什么问题？

(ns adventofcode.day6
  (:require [clojure.java.io :as io]
            [clojure.string :as string]))

(set! *warn-on-reflection* true)

(def ^:const grid-size 1000)

(defn make-grid []
  (let [grid (make-array Long/TYPE grid-size grid-size)]
    (doseq [i (range grid-size)
            j (range grid-size)]
      (aset grid i j -1))
    grid))

(defn parse-line [l]
  (let [[command left-top right-bottom]
        (-> l
            (string/replace "turn off" "turn-off")
            (string/replace "turn on" "turn-on")
            (string/replace "through " "")
            (string/split #" "))
        parse-coordinates (fn [s]
                            (let [parts (string/split s #",")]
                              (map #(Integer/parseInt %) parts)))
        [left top] (parse-coordinates left-top)
        [right bottom] (parse-coordinates right-bottom)]
    [command left top right bottom]))

(defn process-line [grid command left top right bottom]
  (doseq [i (range left (inc right))
          j (range top (inc bottom))]
    (case command
      "turn-off" (aset grid i j -1)
      "turn-on"  (aset grid i j 1)
      "toggle"   (aset grid i j (* -1 (aget grid i j)))
      (throw (Exception. "unrecognized command")))))

(defn count-lights [grid]
  (reduce + (for [i (range grid-size)
                  j (range grid-size)
                  :let [value (aget grid ^Long i ^Long j)]
                  :when (pos? value)]
              value)))

(defn the-answer []
  (with-open [rdr (-> "input-day6.txt"
                      io/resource
                      io/reader)]
    (let [grid (make-grid)]
      (doseq [l (line-seq rdr)]
        (apply process-line grid
               (parse-line l)))
      (count-lights grid))))

编辑：我已经重写了瞬态向量的解决方案,它具有相当不错的性能(Macbook Air上11秒,Macbook Pro上7秒)

(ns adventofcode.day6faster
  (:require [clojure.java.io :as io]
            [clojure.string :as string]))

(set! *warn-on-reflection* true)

(def ^:const grid-size 1000)

(defn make-grid []
  (vec (repeat (* grid-size grid-size) -1)))

(defn parse-line [l]
  (let [[command left-top right-bottom]
        (-> l
            (string/replace "turn off" "turn-off")
            (string/replace "turn on" "turn-on")
            (string/replace "through " "")
            (string/split #" "))
        parse-coordinates (fn [s]
                            (let [parts (string/split s #",")]
                              (map #(Integer/parseInt %) parts)))
        [left top] (parse-coordinates left-top)
        [right bottom] (parse-coordinates right-bottom)]
    [command left top right bottom]))

(defn set-grid! [t-grid grid-size i j v]
  (let [pos (+ i (* j (dec grid-size)))]
    (assoc! t-grid pos v)))

(defn update-grid! [t-grid grid-size i j f]
  (let [pos (+ i (* j (dec grid-size)))]
    (assoc! t-grid pos
            (f (get t-grid pos)))))

(defn process-line [t-grid command left top right bottom]
  (doseq [i (range left (inc right))
          j (range top (inc bottom))]
    (case command
      "turn-off" (set-grid! t-grid grid-size i j -1)
      "turn-on"  (set-grid! t-grid grid-size i j 1)
      "toggle"   (update-grid! t-grid grid-size i j (fn [i] (* -1 i)))
      (throw (Exception. "unrecognized command")))))

(defn count-lights [grid]
  (count (filter pos? grid)))

(defn the-answer []
  (with-open [rdr (-> "input-day6.txt"
                      io/resource
                      io/reader)]
    (let [t-grid (transient (make-grid))]
      (doseq [l (line-seq rdr)]
        (apply process-line t-grid
               (parse-line l)))
      (count-lights (persistent! t-grid)))))

编辑2：现在有循环,类型提示和单个可变数组.我的Macbook Air上1.5秒！

(ns adventofcode.day6singlearray
  (:require [clojure.java.io :as io]
            [clojure.string :as string]))

(set! *warn-on-reflection* true)
(set! *unchecked-math* :warn-on-boxed) 

(def ^:const grid-size 1000)

(defn make-grid []
  (let [l (* grid-size grid-size)
        a (make-array Long/TYPE l)]
    (loop [i 0]
      (if (< i l)
        (do (aset ^longs a i -1)
            (recur (inc i)))
        a))))

(defn parse-line [l]
  (let [[command left-top right-bottom]
        (-> l
            (string/replace "turn off" "turn-off")
            (string/replace "turn on" "turn-on")
            (string/replace "through " "")
            (string/split #" "))
        parse-coordinates (fn [s]
                            (let [parts (string/split s #",")]
                              (map #(Integer/parseInt %) parts)))
        [left top] (parse-coordinates left-top)
        [right bottom] (parse-coordinates right-bottom)]
    [command left top right bottom]))

(defn set-grid! [grid ^long i ^long j v]
  (let [pos (+ i (* j (dec grid-size)))]
    (aset ^longs grid pos ^long v)))

(defn toggle-grid! [grid ^long i ^long j]
  (let [pos (+ i (* j (dec grid-size)))]
    (aset ^longs grid pos
             ^long (* -1 (aget ^longs grid pos)))))

(defn process-line [grid command left top right bottom]
  (let [operation (case command
                    "turn-off" #(set-grid! grid %1 %2 -1)
                    "turn-on"  #(set-grid! grid %1 %2 1)
                    "toggle"   #(toggle-grid! grid %1 %2)
                    (throw (Exception. "unrecognized command")))]
  (loop [^long i left
         ^long j top]
    (if (<= i ^long right)
      (if (<= j ^long bottom)
        (do (operation i j)
            (recur i (inc j)))
        (recur (inc i) top))))))    

(defn count-lights [grid]
  (count (filter pos? grid)))

(defn the-answer []
  (with-open [rdr (-> "input-day6.txt"
                      io/resource
                      io/reader)]
    (let [grid (make-grid)]
      (doseq [l (line-seq rdr)]
        (apply process-line grid
               (parse-line l)))
      (count-lights grid))))