Lisp經典算法
阿新 • • 發佈：2018-03-26
efi init sdn mar class IT rate 均值 gpo
求平方根
SUCCESSIVE AVERAGING DUE TO HERON OF ALEXANDRIA
** TO FIND AN APPROXIMATION TO SQRT(X) **
- MAKR A GUESS G
- IMPROVE THE GUESS BY AVERAGING G AND X/G
- KEEP IMPROVING THE GUESS UNTILE IT IS GOOD ENOUGH
USE 1 AS AN INITIAL GUESS
算法思想
(define (try guess x) (if (good-enough? guess x) guess (try (improve guess x) x))) (define (sqrt x) (try 1 x))參考代碼
註：此代碼來自https://blog.csdn.net/jazz_charles/article/details/48974029
(define (square x) (* x x)) //定義求平方 (define (average x y) (/ (+ x y) 2)) //定義求平均值 (define (sqrt x) //定義求平方根 (define (accurate guess) //定義判斷精確度 (< (abs (- (square guess) x)) 0.001)) (define (improve guess) //定義改進近似值 (average x (/ x guess))) (define (sqrt-iter guess) //定義主體叠代求解 (if (accurate guess) guess (sqrt-iter (improve guess)))) (sqrt-iter 1.0))
Lisp經典算法