spline erros and problems

[jcastanheira]

Dear all,

I have been trying to do a cubic spline for on a mechanical spectral response. Unfortunately the spline does not work, can anyone explain to me why is this happening?

I have used it in the past many times, without any problems(different data).

Is there a easy solution for this ?

Cheers to all!

João

[Werner_E]

The problem is, that you have a lot of duplicate values in your abscissa vector XE1 and thats what Mathcad's spline interpolation chokes at.

[VladimirN]

More accuracy is needed in the source data?

[Werner_E · Accepted solution]

Here is a quick solution.

A routine which sorts and removes lines in a matrix when the elements in the first column are duplicates.

Only the first line will survive. A more sophisticated approach maybe would average the values in the other columns rather than throwing away all but the first.

[jcastanheira]

Thank you all!

Werner! Thats amazing. Thanks!