cyrille henry cyrille.henry at la-kitchen.fr
Wed Jun 25 22:33:35 CEST 2008

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Charles Henry a écrit :
> On Wed, Jun 25, 2008 at 10:32 AM, Matt Barber <brbrofsvl at gmail.com> wrote:
>> For what it's worth, here's supercollider's cubic interpolation
>> function, which differs from csound's and Pd's, which I believe are
>> equivalent:
>>
>> static float cubicinterp(float x, float y0, float y1, float y2, float y3)
>> {
>>        // 4-point, 3rd-order Hermite (x-form)
>>        float c0 = y1;
>>        float c1 = 0.5f * (y2 - y0);
>>        float c2 = y0 - 2.5f * y1 + 2.f * y2 - 0.5f * y3;
>>        float c3 = 0.5f * (y3 - y0) + 1.5f * (y1 - y2);
>>
>>        return ((c3 * x + c2) * x + c1) * x + c0;
>> }
>>
>>
>> Matt
>
>
> a0=(3b-a-3c+d)/2            (same as c3)
> a1=a-5b/2+2c-d/2           (same as c2)
> a2=(c-a)/2                      (same as c1)
>
> (b is c0)
>
> f(x)=(((a0*x+a1)*x+a2)*x-+b
>
> Actually that's just the same set of coefficients that I named in a
> previous post... just in a different form.
yes,
and it's certainly the best i tried.

> So, that's just the sort
> of thing we could add to pd-extended....
I agree
so finally, what should be the name of this object?

is it ok if i remove the other test i made and to use only this one?

cyrille

> It's good to know what other people are doing in their software too
>
> Chuck
>
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