  Diffusion models generate high-quality images but require dozens of forward
passes. We introduce Distribution Matching Distillation (DMD), a procedure to
transform a diffusion model into a one-step image generator with minimal impact
on image quality. We enforce the one-step image generator match the diffusion
model at distribution level, by minimizing an approximate KL divergence whose
gradient can be expressed as the difference between 2 score functions, one of
the target distribution and the other of the synthetic distribution being
produced by our one-step generator. The score functions are parameterized as
two diffusion models trained separately on each distribution. Combined with a
simple regression loss matching the large-scale structure of the multi-step
diffusion outputs, our method outperforms all published few-step diffusion
approaches, reaching 2.62 FID on ImageNet 64x64 and 11.49 FID on zero-shot
COCO-30k, comparable to Stable Diffusion but orders of magnitude faster.
Utilizing FP16 inference, our model generates images at 20 FPS on modern
hardware.
