Hi,
I realized that the code for the fibonacci functions in the codepatterns
section is wrong: http://www.newlisp.org/CodePatterns.html#toc-5
The code is:
; slow and resource hungry
(define (fib n)
(if (< n 2) 1
(+ (fib (- n 1))
(fib (- n 2)))))
> (fib 12)
233
Should be:
; slow and resource hungry
(define (fib n)
(if (< n 2) n
(+ (fib (- n 1))
(fib (- n 2)))))
> (fib 12)
144
The iterative version should be fixed also, something like
that should be correct:
; fast and also returns the whole list
(define (fibo n , f)
(set 'f '(1 0))
(case n
(0 (1 f))
(1 f)
(true
(dotimes (i (- n 1))
(push (+ (f 0) (f 1)) f)))))
> (fibo 12)
(144 89 55 34 21 13 8 5 3 2 1 1 0)
It depends what you define as the
The expression
The expression
The original Fibonacci sequence does not contain a result for (fibo 0) (see the "rabbit" example), and one could argue, that the result for (fibo 0) should not be included but is undefined.
The first form is also faster for the same result:
> (time (println (fib1 29)))
832040
459.522
> (time (println (fibn 30)))
832040
738.925
>