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a sieve/filter-function - filters specific INTERVALS and replacing the others by rests.

(don't work perfect, but as a sketch....)




(defun equal/or (n alist)
  (car (loop for i in alist
         when (equal i n) collect 't)))


(defun filter-omn-by-intervals (omn-seq intervals)
  (setf omn-seq
        with omn-events = (single-events omn-seq)
        with i = 0
        while (not (null (nth i omn-events)))

        when (equal/or (car (pitch-to-interval (append (omn :pitch (nth i omn-events))
                                                (omn :pitch (nth (1+ i) omn-events)))))
        collect  (list (nth i omn-events) (nth (1+ i) omn-events))
        and do (incf i 2)
        else collect (neg! (car (omn :length (nth i omn-events))))
        and do (incf i))))


(setf basic-omn-seq (make-omn :pitch (vector-to-pitch '(c4 c6)
                                                      (gen-white-noise 100 :type :logistic))
                              :length '(t)
                              :span :pitch))

;;; check out all these filter-tests
(setf omn-seq (filter-omn-by-intervals basic-omn-seq '(1 2 3)))
;(setf omn-seq (filter-omn-by-intervals basic-omn-seq '(3 -3)))
;(setf omn-seq (filter-omn-by-intervals basic-omn-seq '(1 -1 5 -5 7 -7)))

(def-score example
           (:title "example"
                   :key-signature 'atonal  
                   :time-signature '(4 4) 
                   :tempo 90) 
   :omn (flatten omn-seq)
   :channel 1
   :sound 'gm-piano)

   :omn (flatten basic-omn-seq)
   :velocity 20
   :channel 3
   :sound 'gm-piano))



here is a more complex example


(defvar library)
(defvar abfolge)
(defvar omn-seq)
(defvar rhy)
(defvar field)

;;;library + rhy --------------------------------------------------------------------------------
(setf rhy 44)
(setf library (list '(eb5 5 p mute)
                    '(e4 5 mf mute)
                    '(gs4 3 f mute)
                    '(g5 3 ppp mute)
                    '(f6 2 p mute)
                    '(cs4 1 f mute)
                    '(d5 1 fff mute)
                    '(b3 4 pppp mute)
                    '(bb5 4 mp mute)
                    '(a4 3 pp mute)
                    '(fs3 (2 7) ppp mute)
                    '(c6 (1 11) mp mute)))

(setf library 
      (loop for i in library 
        collect (append (list (car i)) (if (listp (cadr i))
                                         (gen-length (list (rnd-pick (cadr i))) rhy)
                                         (gen-length (list (cadr i)) rhy))
                        (filter-last 2 i))))

;;; gen seq from library/abfolge---------------------------------------------------------------

(setf field '(eb5 e4 gs4 g5 f6 cs4 d5 b3 bb5 a4 fs3 c6))

(setf abfolge (pick-norepeat 500 field))

(setf omn-seq (loop for x in abfolge 
                with y 
                do (setf y (assoc x library))
                append (append (reverse (filter-first 2 y)) (filter-last 2 y))))

(setf basic-omn-seq omn-seq)

(setf omn-seq (filter-omn-by-intervals basic-omn-seq 
                                       '(1 -1 11 -11 13 -13
                                         4 -4 8 -8 16 -16 20 -20 28 -28 32 -32
                                         7 -7 19 -19)))


(def-score example2
           (:title "example2"
                   :key-signature 'atonal  
                   :time-signature '(4 4) 
                   :tempo 90) 
   :omn (flatten omn-seq)
   :channel 1
   :sound 'gm-piano)

   :omn (flatten basic-omn-seq)
   :channel 1
   :velocity 0
   :sound 'gm-piano))


(omn-list-plot (flatten omn-seq) :join-points t)


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