feelfree feelfree - 4 months ago 17
C++ Question

How to fit the 2D scatter data with a line with C++

I used to work with MATLAB, and for the question I raised I can use p = polyfit(x,y,1) to estimate the best fit line for the scatter data in a plate. I was wondering which resources I can rely on to implement the line fitting algorithm with C++. I understand there are a lot of algorithms for this subject, and for me I expect the algorithm should be fast and meantime it can obtain the comparable accuracy of polyfit function in MATLAB.


I would suggest coding it from scratch. It is a very simple implementation in C++. You can code up both the intercept and gradient for least-squares fit (the same method as polyfit) from your data directly from the formulas here


These are closed form formulas that you can easily evaluate yourself using loops. If you were using higher degree fits then I would suggest a matrix library or more sophisticated algorithms but for simple linear regression as you describe above this is all you need. Matrices and linear algebra routines would be overkill for such a problem (in my opinion).