Can see my post here https://news.ycombinator.com/item?id=21301117 https://news.ycombinator.com/item?id=21301117 I derive the normal equations in just two lin

Can see my post here https://news.ycombinator.com/item?id=21301117 https://news.ycombinator.com/item?id=21301117 I derive the normal equations in just two lines of matrix algebra, never use calculus, assume nothing about probability. The normal equations are plenty simple to program in nearly any programming language. For the linear algebra, just use LINPACK or for a really simple approach just write your own Gauss elimination linear equations solver.