A General Framework for Inference-time Scaling and
Steering of Diffusion Models
Introduces Feynman-Kac steering, an inference-time steering framework for sampling diffusion models guided by a reward function. It generates multiple samples (particles) like best-of-n (importance sampling) approaches. Particles are evaluated at intermediate steps, where they are scored with functions called potentials. Potentials are defined using intermediate rewards and are selected such that promising particles are resampled and poor samples are terminated.
"FK steering with just k = 4 particles outperforms
fine-tuning on prompt fidelity and aesthetic quality, without making use of reward gradients."
"FK steering smaller diffusion models outperforms larger models, and their fine-tuned versions, using less compute."