Matlab's spline equivalent in Python, three inputs.

Question

I\'m converting a matlab script to python and I have it a roadblock. In order to use cubic spline interpolation on a signal. The script uses the command spline with three input

Answer 1

Have you tried the InterpolatedUnivariateSpline within scipy.interpolate? If I understand the MatLab part correctly, then I think this will work.

import numpy as np
from scipy.interpolate import InterpolatedUnivariateSpline as ius

a = [1,2,3,4,5,6]
b = [r * 2 for r in a]
c = ius(a, b, k=1)

# what values do you want to query?
targets = [3.4, 2.789]

interpolated_values = c(targets)

It seems this may add one more step to your code than what MatLab provides, but I think it is what you want.

Answer 2

Basically you will first need to generate something like an interpolant function, then give it your points. Using your variable names like this:

from scipy import interpolate
tck = interpolate.splrep(f_o, c_signal, s=0)

and then apply this tck to your points:

c_interp = interpolate.splev(freq, tck, der=0)

For more on this your can read this post.