🔧 Demystifying loss.backward(): How PyTorch Autograd Actually Works

If you use PyTorch, there’s one line of code you probably type out of sheer muscle memory: loss.backward().

When you first learn neural networks, you spend hours deriving backpropagation equations and understanding chain rules. Then you meet PyTorch, type loss.backward(), and it just... works. It feels like magic. All that complex calculus is...