Training Neural Networks: Backprop, Regularization, and Everything in Between
One number at the end of the network has to become an instruction for every number inside it. That trip is the whole of training: backpropagation as the chain rule run backwards through a graph, the product of many numbers that decides whether the instruction survives the journey, the initialization arithmetic that keeps that product near one and the normalization, clipping and precision choices that answer the other half of the problem, and regularization as the deliberate corruption that makes the result generalize — every claim carried by one worked example, from two weights done by hand to a network that overfits.