How is delta from the polyval function calculated

Hello,

I have to translate a script from matlab to python. Most works well so far, I only have an issue with the polyfit/polyval functions.

polyval in Matlab returns a delta, the equivalent python function doesn't. I have from the python polyfit function a structure that contains "Residuals is sum of squared residuals of the least-squares fit, the effective rank of the scaled Vandermonde coefficient matrix, its singular values, and the specified value of rcond." Or alternatively, a covariance matrix.

Can you give me some pointers how I can get the delta values from those structures?

Greetings,

Johannnes

Answer 1

[Cris LaPierre]

Rather than recreate a MATLAB function in Python, why not just call MATLAB from inside Python?

https://www.mathworks.com/help/matlab/matlab_external/call-matlab-functions-from-python.html

[Johannes Bretscher]

I need to do this, because I do not have a running matlab in my production environment.

I found this: https://codereview.stackexchange.com/questions/84414/obtaining-prediction-bands-for-regression-model which might be what I am looking for.

Thanks for your time.