[CM] lisp loop iteration in cm

Juan I Reyes juanig@ccrma.Stanford.EDU
Thu, 14 Sep 2006 19:40:27 -0400

Hi Rick,

I have been trying to implement the following Lisp function for the
Henon map in CM with no success. Perhaps I am missing something in the
way loops are implemented in CM and therefore I thought may be you could
guide me a little o bit or give some clues on how would be the best way
to deal with this sort of Lisp loops in CM. I just want to output a MIDI
note after each Iteration inside a dotimes Lisp loop and update present
and past values.

  Thanks a lot!

  --* Juan

;;; normalize output from Henon function
(defun midinormz (x)
  (let ((offset 1.0)
	(maxinput 2.0)
	(slope 1.25)
	(maxoutput 127.0)
	(c 0.75)
	(lowbound 15))
    (floor (+ (* (/ (+ x offset) (* maxinput slope))
		 (+ maxoutput c))
	      lowbound)) ))

;;; Henon map function with initial conditions:
(defun henon (cycl &key
		(a -1.85039)  ;; a=-1.56693 b= -0.011811
		(b 0.003937)
		(x 0.63135448)
		(y  0.18940634) )
  (dotimes (i cycl)
    (let ((newx (+ (* a (expt x 2)) (* b y) 1))
	  (newy x))
      (setf x newx)
      (setf y newy))
    (format t ";;; henon values: X: ~f Y: ~f  ~%" (midinormz x)
(midinormz y))

;;; (henon 12)