[nerdponx]

I've heard legends of people fitting shallow feedforward NNs with pure Excel formulas.

I once interned for an economist who was using recursive Excel formulas for some kind of iterative optimization algorithm. I don't remember what it was, probably some iterative least squares thing.

I also was a research assistant for an economist who fit linear regressions with hand-written routines in Matlab. For some reason they felt more comfortable using Matlab's QR decomposition instead of just using the built-in linear modeling tools in R or even Stata.

Some people just want to use their favorite tool even if it makes no sense to do so.

[7thaccount]

Doesn't Matlab fit equations like that easily in a built-in fashion? Why use hand written routines?

[nerdponx]

I had that thought as I was writing this post. I have no idea.