用约束训练生成可适配不同规模的模型初始化模板
Constraint-based Pre-training: From Structured Constraints to Scalable Model Initialization

- 预训练时引入结构化约束,分离通用知识与规模参数
- 新方法在多任务中实现跨尺度模型快速初始化,性能领先
- 适用于各类架构,尤其适合需要灵活部署的场景
预训练-微调范式已成为模型适配的主流方式。然而,传统预训练通常生成固定规模的模型,而实际部署常需不同大小的模型,导致预训练规模与目标不匹配时性能受限。为此,本文提出一种基于约束的预训练范式,在预训练中施加结构化约束,将与规模无关的知识解耦为可复用的权重模板,并将规模相关适配交给轻量级权重缩放器处理,从而将可变规模模型初始化重构为多任务适配问题。在此范式下,我们进一步提出WeiT,采用基于Kronecker的约束正则化预训练过程。模型参数通过拼接和加权聚合表示为权重模板的组合,自适应连接由轻量级权重缩放器控制,其参数从少量数据中学习。该设计支持在多种下游规模下高效构建模型权重。大量实验表明,WeiT在图像分类、图像生成、具身控制等感知与具身学习任务中,对不同深度与宽度的模型均能实现最优初始化效果,且在基于Transformer和卷积的架构上均表现出更快收敛与更高性能,即使在全量训练下也持续提升表现。
原文摘要 · Abstract (English)
The pre-training and fine-tuning paradigm has become the dominant approach for model adaptation. However, conventional pre-training typically yields models at a fixed scale, whereas practical deployment often requires models of varying sizes, exposing its limitations when target model scales differ from those used during pre-training. To address this, we propose an innovative constraint-based pre-training paradigm that imposes structured constraints during pre-training to disentangle size-agnostic knowledge into reusable weight templates, while assigning size-specific adaptation to lightweight weight scalers, thereby reformulating variable-sized model initialization as a multi-task adaptation problem. Within this paradigm, we further introduce WeiT, which employs Kronecker-based constraints to regularize the pre-training process. Specifically, model parameters are represented as compositions of weight templates via concatenation and weighted aggregation, with adaptive connections governed by lightweight weight scalers whose parameters are learned from limited data. This design enables flexible and efficient construction of model weights across diverse downstream scales. Extensive experiments demonstrate the efficiency and effectiveness of WeiT, achieving state-of-the-art performance in initializing models with varying depths and widths across a broad range of perception and embodied learning tasks, including Image Classification, Image Generation, and Embodied Control. Moreover, its effectiveness generalizes to both Transformer-based and Convolution-based architectures, consistently enabling faster convergence and improved performance even under full training.
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