[PD] better tabread4~

[Atwood, Robert C]

> -----Original Message-----
> From: pd-list-bounces at iem.at [mailto:pd-list-bounces at iem.at] 
> On Behalf Of cyrille henry
> Sent: 10 June 2008 16:30
> To: Charles Henry
> Cc: pd-list at iem.at
> Subject: Re: [PD] better tabread4~
> 
> 
> 
> Charles Henry a écrit :
> > On Tue, Jun 10, 2008 at 4:43 AM, cyrille henry
> > <cyrille.henry at la-kitchen.fr> wrote:
> > 
> >> i realized that the 4 points interpolation in tabread4~ 
> (and tabosc4~) are not optimal.
> > 
> > Please describe.  I've analyze the interpolation formula too, and I
> > think that it is a true cubic interpolation.  Is the numerical
> > accuracy bad?
> 
> well, i think the tabread4~ interpolation is a lagrange 
> interpolator (but i'm may be wrong).
> at least with tabread4~, the 1st derivative is not 
> continuous, while it should be with a cubic interpolation.
> 
> i program a cubic interpolation, and the shape of the 
> waveform is really different.

Are we talking about 4-point polynomial interpolation versus cubic spline interpolation? These are indeed different.