# [Data regression] Levenberg-Marquardt BUT force to intersect 2 KNWON points

Hi,

I have a large data set (2D Coordinates with errors) and i am using the Levenberg-Marquardt method to estimate the best polynomial function.
That part is working fine.

Now in my data set are exactly two KNOWN data points that are 100% correct. Therefore I want my function to go through these two points and fit the curve considering the other datapoints.

My polynom currently looks like
$$y=a_3*x^3+a_2*x^2+a_1*x+a_0$$

One idea I had, was to weight the two known points with very high values. But the result still is not correct.

Any Ideas – or maybe an idea of a totally other solution is welcome. I'm working more than a week on LM :-(

Thanks