[SciPy-user] Polynomial interpolation

Robert Kern robert.kern@gmail....
Sun Apr 20 19:10:14 CDT 2008

On Sat, Apr 19, 2008 at 4:27 PM, Anne Archibald
<peridot.faceted@gmail.com> wrote:

>  They all need work, in particular, efficiency would be improved by
>  making the y values vectors, error checking needs to be more robust,
>  and documentation is not in reST form. Ultimately, too, the evaluation
>  functions at least should be written in a compiled language (cython?).
>  But I thought I'd solicit comments on the code first - is the
>  object-oriented design cumbersome?

It looks fine although Gabriel's suggestions would be good
improvements. Some people may want single-function interfaces (e.g.
krogh(xi, yi, x)); they can be written on top of the OO implementation
rather more easily than otherwise.

>  Is including the algorithm in the
>  name confusing to users?

I doubt it.

>  Is the calling convention for Hermite
>  polynomials too confusing or error-prone?

It looks fine to me. For PiecewisePolynomial, I might transpose the yi
input such that yi[0] is the function value, yi[1] is the first
derivative, etc. A nitpick: the code

   pos[pos==-1] = 0
   pos[pos==self.n-1] = self.n-2

can be replaced with

   pos.clip(0, self.n-2, out=pos)

But this all looks good, and I want it in scipy.

Robert Kern

"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
 -- Umberto Eco

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