Training-Free Bayesianization for Low-Rank Adapters of Large Language Models
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Abstract (arXiv)
Estimating the uncertainty of responses from Large Language Models (LLMs) remains a critical challenge. While recent Bayesian methods have demonstrated effectiveness in quantifying uncertainty through low-rank weight updates, they typically require complex fine-tuning or post-training procedures. In this paper, we propose Training-Free Bayesianization (TFB), a simple yet theoretically grounded framework that efficiently transforms trained low-rank adapters into Bayesian ones without additional training. TFB systematically searches for the maximally acceptable level of variance in the weight posterior, constrained within a family of low-rank isotropic Gaussian distributions. Our theoretical analysis shows that under mild conditions, this search process is equivalent to KL-regularized variational optimization, a generalized form of variational inference. Through comprehensive experiments, we show that TFB achieves superior uncertainty estimation and generalization compared to existing methods while eliminating the need for complex Bayesianization training procedures. Code will be available at https://github.com/Wang-ML-Lab/bayesian-peft.
Key facts. Cited by 10 papers in the map (data through 7 Oct 2026). Builds on 50 of its 69 references that are in the map. First posted on arXiv 7 Dec 2024.
Builds on
50 of 69 references.
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Built on by
Citing papers per year: 2025: 3; 2026: 7.
10 papers.
- 2025TokUR: Token-Level Uncertainty Estimation for Large Language Model Reasoningcited by 24
- 2025Toward Efficient Uncertainty in LLMs through Evidential Knowledge Distillationcited by 2
- 2026Bayesian-LoRA: Probabilistic Low-Rank Adaptation of Large Language Modelscited by 2
- 2026Scalable Variational Bayesian Fine-Tuning of LLMs via Orthogonalized Low-Rank Adapterscited by 2
- 2025Dist2ill: Distributional Distillation for One-Pass Uncertainty Estimation in Large Language Modelscited by 1
- 2026Efficient Epistemic Uncertainty Estimation for Large Language Models via Knowledge Distillationcited by 1
- 2026Bayesian Sparse Low-Rank Adaptation for Large Language Model Uncertainty Estimationcited by 1
- 2026Perturbation-Based Epistemic Uncertainty for Failure Detection in Vision-Language-Action Modelscited by 0
- 2026Bayesian Adaptation Gym: A Benchmark for the Bayesian Low-Rank Adaptation of Multi-Modal Language Modelscited by 0
- 2026Certification Frontiers for Gaussian LoRA: Independent Priors, Posterior Risk, and Prediction-Preserving Balancingcited by 0
- 2026Certification Frontiers for Gaussian LoRA: Independent Priors, Posterior Risk, and Prediction-Preserving Balancing26 Sep 2026
- 2026Bayesian Sparse Low-Rank Adaptation for Large Language Model Uncertainty Estimation2 Jul 2026
- 2026Bayesian Adaptation Gym: A Benchmark for the Bayesian Low-Rank Adaptation of Multi-Modal Language Models20 Jun 2026
- 2026Perturbation-Based Epistemic Uncertainty for Failure Detection in Vision-Language-Action Models18 Jun 2026
- 2026Scalable Variational Bayesian Fine-Tuning of LLMs via Orthogonalized Low-Rank Adapters3 Apr 2026
- 2026Efficient Epistemic Uncertainty Estimation for Large Language Models via Knowledge Distillation2 Feb 2026
- 2026Bayesian-LoRA: Probabilistic Low-Rank Adaptation of Large Language Models28 Jan 2026
- 2025Toward Efficient Uncertainty in LLMs through Evidential Knowledge Distillation24 Jul 2025
- 2025TokUR: Token-Level Uncertainty Estimation for Large Language Model Reasoning16 May 2025
- 2025Dist2ill: Distributional Distillation for One-Pass Uncertainty Estimation in Large Language Models16 May 2025