メモ化再帰実験

memotest.clj

(defn fib [n]
  (let [a-fib (atom false)]
    (reset! a-fib (memoize (fn [n] (if (< 1 n) (+ (@a-fib (- n 1)) (@a-fib (- n 2))) 1))))
    (@a-fib n)
    ))

;;; inspired by @tnoda
(def ^:dynamic *m-fib*)
(defn fibv [n]
  (binding [*m-fib* (memoize (fn [x] (if (< 1 x) (+ (*m-fib* (- x 1)) (*m-fib* (- x 2))) 1)))]
    (*m-fib* n)
    ))

memotest.txt

plaster@chloe:~/src/clojure-1.5.0-RC1> java -cp clojure-1.5.0-RC1.jar clojure.main
Clojure 1.5.0-RC1
user=> (defn fib [n]
  (let [a-fib (atom false)]
    (reset! a-fib (memoize (fn [n] (if (< 1 n) (+ (@a-fib (- n 1)) (@a-fib (- n 2))) 1))))
    (@a-fib n)
    ))
#'user/fib
user=> (fib 60)
2504730781961