if your data is already sorted in arrays, consider to use MathNet.Numerics.Interpolation.Barycentric.InterpolateRationalFloaterHormannSorted instead, which is more efficient.
Parameters
IEnumerable<double>
points
The sample points t.
IEnumerable<double>
values
The sample point values x(t).
Return
IInterpolation
An interpolation scheme optimized for the given sample points and values, which can then be used to compute interpolations and extrapolations on arbitrary points.