Data Parallel DDP From Scratch
DistributedDataParallel is a hook on top of allreduce. Wrap a model, broadcast the initial parameters from rank 0 so every rank starts identical, install a backward hook on every parameter that issues an allreduce of the gradient, and the rest is gradient descent. The whole pattern is 200 lines.
Visual edition planned
This lesson isn’t interactive yet.
It is part of the curriculum and will get the same treatment as Phase 1 — a visual cover, hands-on labs, derivations with numeric checks and a quiz. Until then, the original lesson is the best place to read it:
Part of Phase 19 — Capstone Projects. Use the previous / next cards below to keep browsing the phase.