You don't need calculus or that notation. See my https://news.ycombinator.com/item?id=21301117 https://news.ycombinator.com/item?id=21301117 in this thread.

You don't need calculus or that notation. See my https://news.ycombinator.com/item?id=21301117 https://news.ycombinator.com/item?id=21301117 in this thread. I keep the math and notation really simple. The only prerequisite is matrix multiplication. I use no calculus or probability. I derive the normal equations in just two simple lines of matrix algebra. If you want software, there is lots of it or you can write your own easily enough: For the matrix work, might use LINPACK or just write a little Gauss elimination routine for yourself.