Interpolation between integers with gen-transition

[TomTolleson]

Hello,

 

I'm hitting a brick wall with m thinking from object-oriented approaches. Basically, I want to create a melody line that "flutters"  pitches in a key corresponding to a bass pitch, and only when that bass pitch occurs. It's easy enough for an "If, then" statement but my attempt to solve this are leading me to take a first step of interpolating between bass pitches (as integers) and manually calculating the remains of the bar manually.
However this is not ideal as I would prefer to use euclidean-rhythm with a rotation, so finding a parametric approach this would be ideal. Here's the general approach I've begun. 

Any advice from people more experienced with LISP is appreciated.

 

(setf bass '((g2)(c3)(a2)(e3)(fs3)))
(setf bassint (pitch-to-integer bass))
=> ((-17) (-12) (-15) (-8) (-6))

;;; create a set of integers from interpolation 
;;; between bass integers (bassint), 
;;; then convert those to pitches

(setf melody (gen-transition 1 10 10 1))

Thanks,

Tom

[Stephane Boussuge]

May be this can help a bit, I've tried this:

 

(setf bass '(g2 c3 a2 e3 fs3))
(setf bassint (pitch-to-integer bass))
;=> (-17 -12 -15 -8 -6)

;;; create a set of integers from interpolation 
;;; between bass integers (bassint), 
;;; then convert those to pitches

(defun linear-interpolation (numbers steps)
  (let ((interpolated-numbers nil))
    (loop for i from 0 below (- (length numbers) 1)
          for number = (nth i numbers)
          for next-number = (nth (1+ i) numbers)
          do (loop for j from 0 to steps
                   do  (push (+ (* (- next-number number)
                                   (/ (float j) steps))
                                number)
                             interpolated-numbers)
                   )
             (push next-number interpolated-numbers))
    (filter-repeat 1 (nreverse interpolated-numbers))))


(setf n-steps 4)
(setf new-ints (mapcar 'round (linear-interpolation bassint n-steps)))


(setf melody (integer-to-pitch new-ints))

(setf sop (filter-tie
           (make-omn
            :pitch (pitch-transpose 24 melody)
            :length '(e)
            :span :pitch
            )))

(setf bas (make-omn
           :pitch bass
           :length '(h)
           :span :pitch
           ))

(ps 'gm :fl (list sop) :bn (list bas) :time-signature '(4 4))

SB.

[TomTolleson]

This is beautiful, @Stephane Boussuge! First use of a for loop and a defined function for me with OM. This opens up a whole new world.

 

Thank you so much!

 

THT
 

 

[TomTolleson]

One question @Stephane Boussuge - what is 'round ?
Context - 

 

(setf new-ints (mapcar 'round (linear-interpolation bassint n-steps)))

 

I'm unable to find that in the documentation.

[Stephane Boussuge]

Here's the doc:

 

Simplified Common Lisp reference - round

JTRA.CZ

 

 

 

[Stephane Boussuge]

Better doc:

 

CLHS: Function FLOOR, FFLOOR, CEILING, FCEILING...

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