Packages

A few torch.* packages are big enough to warrant their own page even though they're not "systems" in the architectural sense. Each is a substantial, user-facing surface area.

Page	What it is
torch.nn	Neural network module library
torch.optim	Optimizers and learning-rate schedulers
torch.utils.data	DataLoader, Dataset, Sampler, multi-worker loading
torch.func	Function transforms (vmap, grad, jvp, vjp, …)
torch.linalg	Numerical linear algebra

These are documented as packages because they're how a typical user interacts with PyTorch. The systems they sit on top of are documented in Systems.