SICP q1.44

gistfile1.scm

; たとえば
; f(0) = 1.0
; f(1) = 3.0
; f(2) = 9.0
; f(3) = 27.0
; f(4) = 81.0
; のとき
; (smooth(f))(1) = 4.333
; (smooth(f))(2) = 13.0
; (smooth(f))(3) = 39.0
; のようになればよい

(define (smooth f)
  (lambda (x)
    (/ (+ (f (- x dx))
          (f x)
          (f (+ x dx)))
       3)))

(define dx 1)
(define (e i) (expt 3.0 i))
(print (e 0))
(print (e 1))
(print (e 2))
(print (e 3))
(print (e 4))
(newline)
(print ((smooth e) 1))
(print ((smooth e) 2))
(print ((smooth e) 3))
(newline)


; smoothed fをrepeatedに与えればよい
; smmothed fは(smooth f)のことなので
;
;(load "./q1.43.scm")
;(define (n-fold-smooth f n)
;  (repeated (smooth f) n))