Is there a function with which I can change randomly a defined number of lengths in a list to rests?

Thanks, Achim

 

(setf alist '(1/4 1/4 1/8 1/8 1/4 1/4))
(setf n 3)
(length-invert '(1/4 1/4 1/8 1/8 1/4 1/4) :section (rnd-sample n (gen-integer 0 (1- (length alist))) :norep t))

 

Something like this:

 

(defparameter durations '(15/16 15/32 1/32 1/32 1/32 61/32 1/32 1/2 1/32 5/32 1/32 13/16 17/32 3/2 9/16 7/16))

(defun length-to-rnd-rest (numb dur-lst)
  (let* ((llst (- (length dur-lst) 1))
         (minnumb (min numb llst))
         (posns (sort-asc (rnd-unique minnumb (gen-integer 0 llst)))))
    (loop for i in dur-lst
          for j from 0
          collect (if (member j posns)
                      (* -1 i) i ))))

(length-to-rnd-rest 5 durations)

 

I get only 4 rests in this example:

(defparameter durations '(15/16 15/32 1/32 1/32 1/32 61/32 1/32 1/2 1/32 5/32 1/32 13/16 17/32 3/2 9/16 7/16))

(length-invert durations :section (rnd-sample 5 (gen-integer 0 (1- (length durations))) :norep t :seed 4))

;; => (15/16 15/32 1/32 1/32 1/32 61/32 1/32 1/2 -5/32 -13/16 1/32 -9/16 17/32 3/2 -1/32 7/16)

 

test/evaluate it again... my output is

 

=> (-15/16 15/32 1/32 1/32 1/32 61/32 1/32 1/2 1/32 -5/32 -1/32 13/16 -17/32 3/2 9/16 -7/16)

 

 

so it's correct

Sometimes its correct, sometimes not ...

Did you tried it with my seed? What was your result?

The seed is not part of the function therefore it will return different output each time.

Check the rnd-seed doc for how to apply seed function into your functions.

Here it is:

 

(defun length-to-rnd-rest (n sequence &key seed)
  (let (state)
    (setf state *init-seed*)
    (setf seed (rnd-seed seed))
    (do-verbose ("length-to-rnd-rest :seed ~s" seed)
      (let* ((len (length sequence))
             (sel (rnd-order
                   (append (gen-repeat n t) (gen-repeat (- len n) nil))
                   :seed (seed)))
             (result (loop for i in sel
                           for j in sequence
                           collect (if (null i) j (* j -1)))))
        (init-state state)
        result))))

 

(setf lengths '(15/16 15/32 1/32 1/32 1/32 61/32 1/32 1/2 1/32 5/32 1/32 13/16 17/32 3/2 9/16 7/16))

(length-to-rnd-rest 5 lengths)
=> (15/16 15/32 1/32 -1/32 1/32 61/32 1/32 -1/2 -1/32 -5/32 1/32 -13/16 17/32 3/2 9/16 7/16)

(length-to-rnd-rest 5 lengths :seed 5)
=> (15/16 -15/32 1/32 1/32 1/32 61/32 1/32 -1/2 1/32 -5/32 1/32 13/16 -17/32 -3/2 9/16 7/16)

 

I could make something more useful with steps, omitting existing rests and of course working with length symbols and events (omn).