automata.clj

(ns cellular-automata-basic)

(definterface AutomataOps
  (^long getCell [^long i ^long j])
  (^long sumEightNeighbors [^long i ^long j])
  (^long urEightNeighMinmax [^long i ^long j])
  (^long rule [^long i ^long j]))

(defprotocol Automata
  (update [this]))

(deftype CellularAutomata [^long nrows ^long ncols ^longs cells ^longs others]
  Automata
  (update [this] (CellularAutomata. ncols nrows
                  (amap cells idx result 
                        (let [idx (long idx)
                              i   (unchecked-remainder idx ncols)
                              j   (if (zero? idx) (long 0) (unchecked-divide idx ncols))]
                          (aset result idx (.urEightNeighMinmax this i j))))
                  others))
  AutomataOps
  (getCell [this i j] (aget cells (+ (unchecked-multiply i ncols) j)))
  (sumEightNeighbors [this i j]
                     (-> (.getCell this (dec i) (dec j))
                         (+ (.getCell this (dec i) j))
                         (+ (.getCell this (dec i) (inc j)))
                         (+ (.getCell this i (inc j)))
                         (+ (.getCell this (inc i) (inc j)))
                         (+ (.getCell this (inc i) j))
                         (+ (.getCell this (inc i) (dec j)))
                         (+ (.getCell this i (dec j)))))
  (urEightNeighMinmax [this i j]
                      (if (or (= i (dec nrows)) (zero? i) (= j (dec ncols)) (zero? j))
                        (.getCell this i j)
                        (let [sum (.sumEightNeighbors this i j)]
                          (if (and (>= sum (aget others 0)) (<= sum (aget others 1)))
                            (aget others 2)
                            (.getCell this i j))))))

(defn random-ca [nrows ncols]
  (CellularAutomata. nrows ncols
                     (let [a (longs (make-array Long/TYPE (* nrows ncols)))]
                       (amap a i result
                             (aset result i (long (rand-int 2)))))
                     (long-array [2 5 1])))

(def a (random-ca 2000 2000))
(def b (random-ca 500 500))

(comment
 (dotimes [_ 100]
   (time
    (dotimes [_ 1]
      (update b))))
 )