Guidance Is Not a Hyperparameter: Learning Dynamic Control in Diffusion Language Models

Fuente: arXiv
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Autori principali: Zhou, Fan, Van de Cruys, Tim
Natura: Preprint
Pubblicazione: 2026
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author Zhou, Fan
Van de Cruys, Tim
author_facet Zhou, Fan
Van de Cruys, Tim
contents Classifier-Free Guidance (CFG) is a widely used mechanism for controlling diffusion-based generative models, yet its guidance scale is typically treated as a fixed hyperparameter throughout generation. This static design yields a suboptimal controllability and quality tradeoff, as the optimal degree of guidance varies across tasks and across different stages of the diffusion process, especially in NLP domain. We recast CFG scale selection as a sequential decision-making problem and propose to learn dynamic guidance trajectories via reinforcement learning. Specifically, we model the guidance scale as a discrete control action selected at each generation step based on the evolving diffusion state, and optimize a policy using Proximal Policy Optimization (PPO) under task-level rewards. Experiments on three controlled NLP generation tasks using discrete diffusion language models demonstrate that adaptive guidance consistently achieves a better balance between controllability and generation quality than fixed-scale strategies. Further analysis of the learned policies reveals distinct and interpretable guidance trajectories across tasks, underscoring the importance of treating guidance as a dynamic control process rather than a static design choice.
format Preprint
id arxiv_https___arxiv_org_abs_2605_07701
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Guidance Is Not a Hyperparameter: Learning Dynamic Control in Diffusion Language Models
Zhou, Fan
Van de Cruys, Tim
Computation and Language
Classifier-Free Guidance (CFG) is a widely used mechanism for controlling diffusion-based generative models, yet its guidance scale is typically treated as a fixed hyperparameter throughout generation. This static design yields a suboptimal controllability and quality tradeoff, as the optimal degree of guidance varies across tasks and across different stages of the diffusion process, especially in NLP domain. We recast CFG scale selection as a sequential decision-making problem and propose to learn dynamic guidance trajectories via reinforcement learning. Specifically, we model the guidance scale as a discrete control action selected at each generation step based on the evolving diffusion state, and optimize a policy using Proximal Policy Optimization (PPO) under task-level rewards. Experiments on three controlled NLP generation tasks using discrete diffusion language models demonstrate that adaptive guidance consistently achieves a better balance between controllability and generation quality than fixed-scale strategies. Further analysis of the learned policies reveals distinct and interpretable guidance trajectories across tasks, underscoring the importance of treating guidance as a dynamic control process rather than a static design choice.
title Guidance Is Not a Hyperparameter: Learning Dynamic Control in Diffusion Language Models
topic Computation and Language
url https://arxiv.org/abs/2605.07701