No Task Left Behind: Isotropic Model Merging with Common and Task-Specific Subspaces
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Abstract (arXiv)
Model merging integrates the weights of multiple task-specific models into a single multi-task model. Despite recent interest in the problem, a significant performance gap between the combined and single-task models remains. In this paper, we investigate the key characteristics of task matrices -- weight update matrices applied to a pre-trained model -- that enable effective merging. We show that alignment between singular components of task-specific and merged matrices strongly correlates with performance improvement over the pre-trained model. Based on this, we propose an isotropic merging framework that flattens the singular value spectrum of task matrices, enhances alignment, and reduces the performance gap. Additionally, we incorporate both common and task-specific subspaces to further improve alignment and performance. Our proposed approach achieves state-of-the-art performance on vision and language tasks across various sets of tasks and model scales. This work advances the understanding of model merging dynamics, offering an effective methodology to merge models without requiring additional training. Code is available at https://github.com/danielm1405/iso-merging .
Key facts. Cited by 96 papers in the map (data through 14 Oct 2026). Builds on 40 of its 59 references that are in the map. First posted on arXiv 7 Feb 2025.
Builds on
40 of 59 references.
References · 40
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- 2022Editing Models with Task Arithmeticcited by 1,120
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- 2017Remote Sensing Image Scene Classification: Benchmark and State of the Artcited by 797
- 2021Robust fine-tuning of zero-shot modelscited by 797
- 2023Language Models are Super Mario: Absorbing Abilities from Homologous Models as a Free Lunchcited by 694
- 2021Merging Models with Fisher-Weighted Averagingcited by 621
- 2018Rotation Equivariant CNNs for Digital Pathologycited by 422
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- 2022Dataless Knowledge Fusion by Merging Weights of Language Modelscited by 387
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- 2022Patching open-vocabulary models by interpolating weightscited by 190
- 2015Compression of Deep Convolutional Neural Networks for Fast and Low Power Mobile Applicationscited by 162
- 2024Task Singular Vectors: Reducing Task Interference in Model Mergingcited by 147
- 2023Model Breadcrumbs: Scaling Multi-Task Model Merging with Sparse Maskscited by 133
- 2024Localizing Task Information for Improved Model Merging and Compressioncited by 131
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- 2023Deep Model Fusion: A Surveycited by 91
- 2023Model Merging by Uncertainty-Based Gradient Matchingcited by 77
- 2024Parameter Competition Balancing for Model Mergingcited by 72
- 2023Orthogonal Adaptation for Modular Customization of Diffusion Modelscited by 70
- 2024MagMax: Leveraging Model Merging for Seamless Continual Learningcited by 67
- 2024SVFT: Parameter-Efficient Fine-Tuning with Singular Vectorscited by 58
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Citing papers per year: 2025: 25; 2026: 71.
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- 2026Train Together or Merge Later? Unifying VLA Experts via a Shared Action Interface27 Sep 2026
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- 2026PivotMerge: Bridging Heterogeneous Multimodal Pre-training via Post-Alignment Model Mergingcited by 2
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- 2026Model Merging for Medical LVLMs: A Benchmark and a Winner-Take-All Approach17 Jul 2026
- 2026Beyond Classification: Dynamic Adapter Routing for Continual Multimodal Retrieval29 May 2026
- 2026PivotMerge: Bridging Heterogeneous Multimodal Pre-training via Post-Alignment Model Merging18 Apr 2026
- 2026SSAM: Singular Subspace Alignment for Merging Multimodal Large Language Models23 Mar 2026
- 2025MergeVLA: Cross-Skill Model Merging Toward a Generalist Vision-Language-Action Agent24 Nov 2025
- 2025Expert Merging: Model Merging with Unsupervised Expert Alignment and Importance-Guided Layer Chunking30 Sep 2025
- 2025Model Merging via Multi-Teacher Knowledge Distillationcited by 2
- 2025Model Merging via Multi-Teacher Knowledge Distillation24 Dec 2025
- 2025Accurate and Efficient Low-Rank Model Merging in Core Spacecited by 29
- 2025RegMean++: Enhancing Effectiveness and Generalization of Regression Mean for Model Mergingcited by 11
- 2025Scalable Model Merging with Progressive Layer-wise Distillationcited by 10
- 2025AdaRank: Adaptive Rank Pruning for Enhanced Model Mergingcited by 9
- 2025Subspace-Boosted Model Mergingcited by 9
- 2026DC-Merge: Improving Model Merging with Directional Consistencycited by 8
- 2026Demystifying Mergeability: Interpretable Properties to Predict Model Merging Successcited by 7
- 2026Model Merging in the Essential Subspacecited by 7
- 2025Why Do More Experts Fail? A Theoretical Analysis of Model Mergingcited by 6
- 2025Model Unmerging: Making Your Models Unmergeable for Secure Model Sharingcited by 6
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- 2026ACE-Merging: Data-Free Model Merging with Adaptive Covariance Estimationcited by 6
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- 2026How Inner Optimizers Shape Replica Scaling13 Oct 2026
- 2026CrossMean: Model Merging by Pairing Merged and Expert Activations10 Oct 2026
- 2026PGSB: Pretrained-Guided Shared Basis for LoRA Model Merging10 Oct 2026
- 2026Training-Free Transformer Merging via Sequential Local Operator Alignment5 Oct 2026
- 2026BACAM: Behavior-Aware Continual Agent Merging for Multi-Turn Interaction4 Oct 2026
- 2026Predicting and Repairing Merge Collapse in Large Language Models2 Oct 2026
- 2026Orthogonal Yet Coupled: Decoupling Geometric Components for Model Merging29 Sep 2026
- 2026CASS: Contribution-Aware Structured Sparsity for Model Merging28 Sep 2026
- 2026MergeHEIR: Mitigating Multimodal Hallucinations as the Tax of Model Merging26 Sep 2026
- 2026Beyond Uniform Subspaces: Spectrum-Aware and Depth-Adaptive Fusion for Multi-Task Model Merging21 Sep 2026
- 2026Not All Task Vectors Need Equal Rank: Energy-Proportional Allocation for Model Merging21 Sep 2026
- 2026Merge++: Universal Merge Refinement Through Data-Free Checkpoint Inversion19 Sep 2026
12 newest of 78 All 78 (JSON)