Interpolate the roots/positions of sign changes

This function interpolates the x-positions of roots/sign changes in the data in y and adds the roots to the vectors.

Interpolate the x-positions of roots/sign changes in the data in y. This is helpful if you want to treat the positive and negative parts of y differently.

Example: has three roots at , and . The vector

x = linspace(-3, 3, 50)

does not include these roots.

y = x.^3 - 4.*x;
[xNew, yNew] = interpolateRoots(x, y)

interpolates the roots to , and and returns the extended vectors xNew and yNew including these interpolated roots at the corresponding positions. xNew and yNew are 53 elements long while x and y contain 50 elements.