Aligning Few-Step Generative Models by Amortizing Sample-based Variational Inference
- URL: http://arxiv.org/abs/2605.26552v2
- Date: Wed, 27 May 2026 07:59:16 GMT
- Title: Aligning Few-Step Generative Models by Amortizing Sample-based Variational Inference
- Abstract summary: We introduce FAV, Few-step Generative Models Alignment via Sample-based Variational Inference.<n>FAV cast alignment as sampling from a reward-tilted distribution anchored to a reference distribution.<n>We evaluate FAV on two domains: robotics manipulation and image generator alignment.
- Score: 60.82875447631739
- License: http://creativecommons.org/licenses/by/4.0/
- Abstract: Aligning a few-step generative model is challenging, since existing alignment frameworks typically rely on restrictive assumptions: a tractable likelihood, a specific ODE/SDE solver, or a particular model family. We introduce FAV, Few-step Generative Models Alignment via Sample-based Variational Inference, a general alignment framework that requires only sample access to the generator and the reference distribution. We cast alignment as sampling from a reward-tilted distribution anchored to a reference distribution. We leverage Stein Variational Gradient Descent as a sample-based variational inference scheme and amortize its particle updates into the generator parameters via fixed-point regression. We evaluate FAV on two domains: robotics manipulation and image generator alignment. On generative policy alignment for robotic manipulation, FAV outperforms prevailing policy extraction baselines across 56 offline and 30 offline-to-online RL tasks. For image generator alignment, FAV fine-tunes diverse few-step backbones, including GAN, drifting model, consistency models, and flow maps, scaling from ImageNet-$256$ to 1024$^2$ text-to-image synthesis. Code is available at https://github.com/Jaewoopudding/FAV.
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