;; this file:
;;   https://dataswamp.org/~incal/cl/bench/fib.cl
;;
;; original Elisp source:
;;   elisp-benchmarks

(load "~/public_html/cl/bench/timing.cl")

;; optimized

(defun fibn (reps num)
  (declare (optimize speed (safety 0) (debug 0)))
  (let ((z 0))
    (declare (type (unsigned-byte 53) reps num z))
    (dotimes (r reps)
      (let*((p1 1)
            (p2 1) )
        (dotimes (i (- num 2))
          (setf z (+ p1 p2)
                p2 p1
                p1 z) )))
    z) )

(defun fibn-entry ()
  (fibn 1000000 80) )

;; tail recursive

(defun fibn-tc (a b count)
  (if (zerop count)
      b
    (fibn-tc (+ a b) a (1- count)) ))

(defun fibn-tc-entry ()
  (dotimes (_ 1000000)
    (fibn-tc 1 0 80) ))

;; naive recursion

(defun fibn-rec (n)
  (cond ((zerop n) 0)
        (  (= 1 n) 1)
        (t (+ (fibn-rec (1- n))
              (fibn-rec  (- n 2)) ))))

(defun fibn-rec-entry ()
  (fibn-rec 37) )

(defun fib-all-entry ()
  (timing (fib-entry))
  (timing (fibn-tc-entry))
  (timing (fibn-rec-entry)) )

(fib-all-entry)