CODEWITHSUNDEEP
pythonmathscipyinterpolationextrapolation
Ahmad Mohammad
Ahmad Mohammad

Reputation: 25

Use y-values as input for interpolation, instead of x

I am predicting the path of a rolling ball using coordinates obtained from my webcam using openCV, by using scipy interpolate.

For the sake of simplicity, just normal arrays of x- and y-values are used.

I can only input x in the function to obtain y. However, I want to be able to get x, by using y as input. It is the inverse interpolated function I want, if that makes sense.

Currently it only works for an input of x, as seen in the code below at f(-100).

from scipy import interpolate

def f(x):
    x_points = [ 0, 1, 2, 3, 4, 5]
    y_points = [12,14,22,39,58,77]

    coeff = interpolate.splrep(x_points, y_points)
    return interpolate.splev(x, coeff)

print(f(-100))

Output when using x as input works just fine, with no error messages given.

Upvotes: 1

Views: 515

Answers (1)

David Kong
David Kong

Reputation: 638

Have you tried switching the arguments? coeff = interpolate.splrep(y_points, x_points)

Upvotes: 1

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