[SciPy-user] Problems with the interpolation package

[Jón Egilsson]

Hi there.

I've now tried various functions in the scipy.interpolate package without
getting far.

*What I want to do:*

I want to interpolate using spline interpolation, cubic spline interpolation
to be more precise.

1. I want to be able to choose which points to interpolate (to choose
between which points on the x-axis the cubic polynomials are). Then I'll
have some polynomials on the form ax^3 + bx^2 + cx + d

2. Then I want to be able to extract the coefficients a,b,c,d from each
polynomial because that's the only thing I want to keep. I don't want to
keep an interpolation object of some sort.

*Input:*

Two lists, one representing the x-axis: [0..n] and another one with the
function values: [y0, y1, y2, ... , yn] and the desired points I wish to
interpolate between.

*Output (preferably):*

The coefficients (a,b,c,d) for every polynomial beetween the points I chose
to interpolate between.

Any help at all will be greatly appreciated. Cheers.

Jón Gísli Egilsson.
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