Advanced NLP Interview Questions, issue 11, Dec 17, 2025
The Argmax Deadlock Trap
Senoir Machine Learning Engineer interview at Google DeepMind, and the interviewer asks:
“We are building a massive Mixture of Experts (MoE) model. To maximize training throughput on our H100 clusters, we want to route each token to only the single best expert (k=1). Is this a valid strategy?”
Hard argmax breaks differentiability in MoE routing, starving experts and freezing the gating network.
The full answer, with the mechanism and the arithmetic, is for paid subscribers on Substack.