Improving Consistency Models with Generator-Augmented Flows
This work addresses a specific bottleneck in consistency models for generative modeling, offering incremental improvements in training efficiency and effectiveness.
The paper tackles the discrepancy between consistency distillation and training in consistency models by proposing a novel flow that transports noisy data towards consistency model outputs, which accelerates convergence and improves performance.
Consistency models imitate the multi-step sampling of score-based diffusion in a single forward pass of a neural network. They can be learned in two ways: consistency distillation and consistency training. The former relies on the true velocity field of the corresponding differential equation, approximated by a pre-trained neural network. In contrast, the latter uses a single-sample Monte Carlo estimate of this velocity field. The related estimation error induces a discrepancy between consistency distillation and training that, we show, still holds in the continuous-time limit. To alleviate this issue, we propose a novel flow that transports noisy data towards their corresponding outputs derived from a consistency model. We prove that this flow reduces the previously identified discrepancy and the noise-data transport cost. Consequently, our method not only accelerates consistency training convergence but also enhances its overall performance. The code is available at: https://github.com/thibautissenhuth/consistency_GC.