FedRot-LoRA: Mitigating Rotational Misalignment in Federated LoRA
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Abstract (arXiv)
Federated LoRA provides a communication-efficient mechanism for fine-tuning large language models on decentralized data. In practice, however, a discrepancy between the factor-wise averaging used to preserve low rank and the mathematically correct aggregation of local updates can cause significant aggregation error and unstable training. We argue that a major source of this problem is rotational misalignment, arising from the rotational invariance of low-rank factorizations -- semantically equivalent updates can be represented in different latent subspaces across clients since (Bi Ri)(Ri^top Ai) = Bi Ai. When such misaligned factors are averaged directly, they interfere destructively and degrade the global update. To address this issue, we propose FedRot-LoRA, a federated LoRA framework that aligns client updates via orthogonal transformations prior to aggregation. This alignment preserves the semantic update while reducing cross-client subspace mismatch, without increasing communication cost or restricting model expressivity. We provide a convergence analysis that examines the aggregation error induced by factor-wise averaging and shows how rotational alignment yields a tighter upper bound on this error. Extensive experiments on natural language understanding and generative tasks demonstrate that FedRot-LoRA consistently outperforms existing federated LoRA baselines across a range of heterogeneity levels and LoRA ranks.
Key facts. Cited by 8 papers in the map (data through 7 Oct 2026). Builds on 27 of its 36 references that are in the map. First posted on arXiv 27 Feb 2026.
Builds on
27 of 36 references.
References · 27
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- 2021The Power of Scale for Parameter-Efficient Prompt Tuningcited by 3,769
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- 2019CodeSearchNet Challenge: Evaluating the State of Semantic Code Searchcited by 638
15 more
- 2020The Future of Digital Health with Federated Learningcited by 625
- 2021Federated Learning on Non-IID Data Silos: An Experimental Studycited by 566
- 2024LoRA+: Efficient Low Rank Adaptation of Large Modelscited by 365
- 2023Towards Building the Federated GPT: Federated Instruction Tuningcited by 184
- 2023Scaling Down to Scale Up: A Guide to Parameter-Efficient Fine-Tuningcited by 171
- 2024Improving LoRA in Privacy-preserving Federated Learningcited by 158
- 2023FederatedScope-LLM: A Comprehensive Package for Fine-tuning Large Language Models in Federated Learningcited by 146
- 2024FLoRA: Federated Fine-Tuning Large Language Models with Heterogeneous Low-Rank Adaptationscited by 144
- 2024Federated Fine-tuning of Large Language Models under Heterogeneous Tasks and Client Resourcescited by 93
- 2022FedPrompt: Communication-Efficient and Privacy Preserving Prompt Tuning in Federated Learningcited by 86
- 2024Selective Aggregation for Low-Rank Adaptation in Federated Learningcited by 80
- 2024FedEx-LoRA: Exact Aggregation for Federated and Efficient Fine-Tuning of Foundation Modelscited by 18
- 2025Robust Federated Finetuning of LLMs via Alternating Optimization of LoRAcited by 17
- 2024Task-Aware Low-Rank Adaptation of Segment Anything Modelcited by 6
- 2025FedSRD: Sparsify-Reconstruct-Decompose for Communication-Efficient Federated Large Language Models Fine-Tuningcited by 5
Built on by
Citing papers per year: 2026: 8.
8 papers.
- 2026SeFoRA: Sketch-Aggregated Federated Low-Rank Adaptation with Heterogeneous Client Rankscited by 1
- 2026FedPA-LoRA: Product-Aligned Framework for Mitigating Aggregation and Initialization Errors in Heterogeneous Federated LoRAcited by 1
- 2026Dysco: Dynamic Subspace Boosting to Mitigate LoRA Interference in Federated Learningcited by 0
- 2026Rethinking Factor Sharing in Federated LoRA: A Rank-Aware Adaptive Approachcited by 0
- 2026Unveiling the Depth-Performance Dilemma in Split-Federated Fine-tuning of LLMscited by 0
- 2026RW-LoRA: Communication-Efficient Decentralized LoRA Fine-Tuning via Random Walkscited by 0
- 2026What Should Federated LoRA Share? FedSAIL via Input-aware Subspace Alignmentcited by 0
- 2026CF-LoRA: Decoupled Factor Aggregation and Adaptation-Aware Client Clustering for Federated LoRA Fine-Tuningcited by 0
- 2026CF-LoRA: Decoupled Factor Aggregation and Adaptation-Aware Client Clustering for Federated LoRA Fine-Tuning29 Sep 2026
- 2026What Should Federated LoRA Share? FedSAIL via Input-aware Subspace Alignment26 Sep 2026
- 2026RW-LoRA: Communication-Efficient Decentralized LoRA Fine-Tuning via Random Walks31 Aug 2026
- 2026Unveiling the Depth-Performance Dilemma in Split-Federated Fine-tuning of LLMs23 Aug 2026
- 2026FedPA-LoRA: Product-Aligned Framework for Mitigating Aggregation and Initialization Errors in Heterogeneous Federated LoRA15 Aug 2026
- 2026SeFoRA: Sketch-Aggregated Federated Low-Rank Adaptation with Heterogeneous Client Ranks10 Aug 2026
- 2026Rethinking Factor Sharing in Federated LoRA: A Rank-Aware Adaptive Approach10 Aug 2026
- 2026Dysco: Dynamic Subspace Boosting to Mitigate LoRA Interference in Federated Learning15 Jul 2026