- 935 名前：934 mailto:sage [04/11/03 17:47:01]
- (define mutate
(lambda (expression)
(let ((op (car expression))
(opr1 (cadr expression))
(opr2 (caddr expression))
(r (random 100)))
(cond
((< r 20)
(list (mutate-operator)
(if (pair? opr1) (mutate opr1) opr1)
(if (pair? opr2) (mutate opr2) opr2)))
((< r 60)
(list op
(if (pair? opr1) (mutate opr1) (mutate-operand opr1))
(if (pair? opr2) (mutate opr2) opr2)))
(else
(list op
(if (pair? opr1) (mutate opr1) opr1)
(if (pair? opr2) (mutate opr2) (mutate-operand opr2))))))))
; (mutate (mutate (mutate (mutate '(* (+ x y) (- x y)) )))) --> (+ (* 0.8420 0.1857) (- (+ x x) 0.9704))
>20% the operator will colapse into an operand according to rule 1
これの意味は不明なのでいれてないよん。
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