;; implementation of classic chaos equation, the logistic map
;; from population biology
;; see http://www-camil.music.uiuc.edu/Classes/icbc/icbc/chaos/main.html
;;

;; needs to have prc96.ins loaded for tubebell voice
;; (compile-file "log" :verbose nil)
;; (load "log")
;; (l)
;;
;; 
;; gv aaa.eps for 1st page of score, gv aaa-1.eps for 2nd pg, etc.

;; the system is very simple --
;; here's a logistic map iterated 20 times with r in chaotic region of 4.0
;; copy this direct into the lisp interpreter and then try r = 2.0, too
; (loop repeat 20 with x = 0.1 as r = 4.0 do (print (setf x (* r x (- 1.0 x)))))

;; function to set up context for a phrase or set of notes
(defun init-globals (start chaos-level seed scr staff-name)
  (setf semit (expt 2.0 (/ 1.0 12.0)))
  (setf x seed)
  (setf r chaos-level)
  (setf now start)
  (setf stf (cmn::add-staff scr staff-name nil))
  )

;; function which will iterate logistic equation one time
(defun lf ()
  (setf x (* r x (- 1.0 x))))

;; function to sound and score a note, notating at twice the time values
(defun note (beg dur freq amp scr)
  (tubebell beg dur freq amp)
  (cmn::add-note-to-staff scr stf (* 2 beg) (* 2 dur) freq)
  )

;; outer function to establish context and then run the whole process
(defun l ()
  (let* 
      (
       (scr (cmn::init-clm-input))
        (n 52)
       dur 
	   pitch
       (thirty-second 0.125)
       )
    (with-sound 
     ;; spec sound output
     (:srate 48000 :output "/zap/test.wav" :channels 2)
     ;; initial a chaos series and add a stave for it, then loop throug its notes
     (loop for i from 0 below n 
       initially (init-globals 0.0 4.0 0.1 scr "fib1") 
       do
       (lf)
       (setf dur (* thirty-second (+ 1.0 (round (/ (* x 0.5) thirty-second)))))
       (setf pitch (* 440.0 (expt semit (round (/ x 0.05)))))
       (note now dur pitch 0.1 scr)
       (setf now (+ now dur))
       )
     ;; do it again on new stave, same chaos
	 ;; but octave down, different seed and sixteenth-rest later
     (loop for i from 0 below n 
       initially (init-globals 0.25 4.0 0.01 scr "fib2") 
       do
       (lf)
       (setf dur (* thirty-second (+ 1.0 (round (/ (* x 0.5) thirty-second)))))
       (setf pitch (* 220.0 (expt semit (round (/ x 0.05)))))
       (note now dur pitch 0.1 scr)
       (setf now (+ now dur))
       )
     )
    (cmn::finish-clm-input scr nil nil)				  
    ))

;; indent me, but change my file name & path to be correct first --below here--
;; xemacs -batch -l ~/.emacs-indent-file -eval '(indent-file "~/220w/log.lisp")'