What is the theory behind fitlm function ?

Hello,

I wonder how the function 'fitlm' work. Actually, I need to compare the linear regression given by Matlab and by another software. I know from theory that the principle is based on minimizing the error (epsilon factor) of equation: y = X*beta * epsilon. It consists of doing: beta = (X^t*X)^-1*X^t*y But concretely, how Matlab does that ?

Thank you very much for your answer !

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