[CM] poly questions

[James Hearon]

Hi,
I think I'm understanding better now.  In order to generate and utilize the correct Chebyshev coefficients with make-polyshape, one needs to specify the kind or type using partials->polynomial to first generate the coefficients.

(partials->polynomial (float-vector 1 1 3 1/3 5 1/5 7 1/7 9 1/9)  mus-chebyshev-second-kind)
;#r(0.8349206349206351 0.0 -2.082539682539683 0.0 18.43809523809524 0.0 -40.63492063492063 0.0 28.44444444444444 0.0

(with-sound (:srate 48000 :channels 1 :play #t)
   (let ((gen (make-polyshape 100.0
          :coeffs #r(0.8349206349206351 0.0 -2.082539682539683 0.0 18.43809523809524 0.0 -40.63492063492063 0.0 28.44444444444444 0.0)  :kind mus-chebyshev-second-kind)))
     (do ((i 0 (+ i 1)))
         ((= i 88200))
       (outa i (* .75 (polyshape gen 1.0))))))


Fantastic.  partials-->polynomial is a nice tool.  There's not that much around that allows one to view the coefficents being used in the synthesis.

...I'll move on and try to get some understanding of the sums.

mus-chebyshev-tu-sum x t-coeffs u-coeffs
mus-chebyshev-t-sum x t-coeffs
mus-chebyshev-u-sum x u-coeffs

thanks,
Jim

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