arXiv AI

Model Merging as Probabilistic Inference in Fine-Tuning Parameter Space

arXiv:2607. 01689v1 Announce Type: cross Abstract: Model merging aims to combine existing single-task solutions into a multi-task solution without additional data-driven fine-tuning.

Hugging Face Trending Papers
Jun 25

Learning to Recover Task Experts from a Multi-Task Merged Model

Multi-task model merging aims to consolidate several task-specific experts into a unified model, yet static merging consistently suffers from parameter interference. While dynamic merging models aim to bridge this gap, many works rely on the costly storage and loading of redundant expert components at inference.

arXiv AI
2d ago

ReForge: Refining Merged Models with Anchor-Regularized Regression

ReForge is a bilevel optimization framework that refines merged models by treating module-wise refinement as Bayesian linear regression with an anchor-centered prior. The inner level produces a closed‑form MAP estimate from unlabeled calibration activations, while the outer level employs Bayesian optimization to jointly select regularization strengths and assembly scales using validation data. A data‑free variant replaces activation statistics with task‑vector Grams, enabling refinement without calibration examples, and across extensive vision and language benchmarks ReForge consistently outperforms existing plug‑and‑play anchor baselines, achieving significant accuracy gains on large‑scale tasks such as 20‑task ViT‑B/32 and eight‑task ViT‑L/14.

By Kaiyang Li, Shaobo Han, Qing Su, Shihao Ji
arXiv Machine Learning
Sep 22

Merge++: Universal Merge Refinement Through Data-Free Checkpoint Inversion

Merge++ is a post‑hoc refinement technique for model merging that synthesizes task‑representative images by inverting expert checkpoints and then distills expert knowledge into a merged model. It operates without any additional data beyond the checkpoints and can be applied universally across existing weight‑space merging algorithms. Experiments show consistent improvements, with average gains of +2 to +8 points and up to +25.9 on specific configurations.

By Aditya Pola, Vineeth N. Balasubramanian
arXiv Machine Learning
Sep 22

CAMFT: Conflict-Aware Mergeable Fine-Tuning for Large Language Models

CAMFT is a Conflict‑Aware Mergeable Fine‑Tuning method designed to make task adaptation efficient and merge‑aware for large language models. Unlike existing approaches that only resolve parameter conflicts after fine‑tuning, CAMFT shapes mergeability during training by guiding each task to update sparse coordinates with lower cross‑task conflict. Experiments show that CAMFT outperforms standard fine‑tuning baselines in multi‑task merging scenarios.

By Jingang Zhou, Haiyang Guo, Yuan Ma, Han Zhu, Xu-Yao Zhang
arXiv Machine Learning
1d ago

Model Merging via Data-Free Covariance Estimation

The paper introduces a data‑free method for model merging that estimates per‑layer covariance matrices directly from difference matrices, eliminating the need for auxiliary data. This approach reduces computational costs while maintaining a principled interference‑minimization framework. Experiments on vision and language benchmarks with models from 86 M to 7 B parameters show that the method outperforms existing data‑free merging techniques.

By Marawan Gamal Abdel Hameed, Derek Tam, Pascal Jr Tikeng Notsawo, Colin Raffel, Guillaume Rabusseau
arXiv Machine Learning
Aug 27

Escaping Low-Dimensional Overlap: Multi-Task Model Merging via High-Dimensional Sparse Disentanglement

The paper introduces a new multi‑task model‑merging framework that tackles task interference by projecting task vectors into a high‑dimensional sparse feature space using Sparse Autoencoders, enabling feature‑level disentanglement before fusion. It also proposes a lightweight Group‑Ranked Zeroth‑Order Optimizer to identify task‑critical layers for selective merging, reducing computational overhead. Experiments on Qwen2.5‑1.5B and Qwen2.5‑7B show consistent performance gains over several baselines across reasoning, code generation, instruction following, and general knowledge tasks, with a 2.78% improvement in a highly conflicting four‑task setting.

By Yihang Zhang, Shengke Sun, Junjie Wen, Feng Zeng