Generative Vision Interview Questions, issue 2, Jun 9, 2026
The Isotropic Shortcut
Senior AI Engineer interview, and the interviewer asks:
“We are training a diffusion model and need to fetch the noisy state at step 500. Code it.”
Why calculating diffusion states step-by-step is a guaranteed training bottleneck, and how the additive property of Gaussians lets you bypass 499 steps in O(1) time.
The full answer, with the mechanism and the arithmetic, is for paid subscribers on Substack.