FoRA: Fisher-orthogonal Rank Adaptation for Parameter-Efficient Fine-Tuning

Fuente: arXiv
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Main Authors: Park, Juneyoung, Lee, Seongbae, Lee, Han-Sang, Lee, Kyuho, Kim, Minjae, Hyeon, Seungheon, Kwon, Kiduk, Kim, Seongwan, Lee, Jaeho
Format: Preprint
Published: 2026
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author Park, Juneyoung
Lee, Seongbae
Lee, Han-Sang
Lee, Kyuho
Kim, Minjae
Hyeon, Seungheon
Kwon, Kiduk
Kim, Seongwan
Lee, Jaeho
author_facet Park, Juneyoung
Lee, Seongbae
Lee, Han-Sang
Lee, Kyuho
Kim, Minjae
Hyeon, Seungheon
Kwon, Kiduk
Kim, Seongwan
Lee, Jaeho
contents Parameter-efficient fine-tuning(PEFT) has largely focused on LoRA and its accuracy-oriented variants, leaving the original goal of reducing trainable parameters has receivedcomparatively little attention. We introduce FoRA, which revisits this goal by reducing the number of adapted layers rather than adapter rank. FoRA selects task-informative layers via a single-pass diagonal Fisher score (under 1% of training cost) and trains the LoRA down-projection at selected layers on the Stiefel manifold, preserving column orthonormality and effective rank. FoRA consistently outperforms LoRA and DoRA at half their parameter budget, and falls within 0.7-0.8 accuracy points of AdaLoRA at one-quarter its parameter count, across five LLaMA-family backbones. Cross-architecture experiments on twelve backbones from the LLaMA, Qwen3, and Gemma families confirm consistent gains from 270M to 32B parameters. The two components combine super-additively: Fisher selection alone matches rank reduction at the same budget, while the Stiefel constraint provides the decisive additional gain.
format Preprint
id arxiv_https___arxiv_org_abs_2605_29317
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle FoRA: Fisher-orthogonal Rank Adaptation for Parameter-Efficient Fine-Tuning
Park, Juneyoung
Lee, Seongbae
Lee, Han-Sang
Lee, Kyuho
Kim, Minjae
Hyeon, Seungheon
Kwon, Kiduk
Kim, Seongwan
Lee, Jaeho
Computation and Language
Parameter-efficient fine-tuning(PEFT) has largely focused on LoRA and its accuracy-oriented variants, leaving the original goal of reducing trainable parameters has receivedcomparatively little attention. We introduce FoRA, which revisits this goal by reducing the number of adapted layers rather than adapter rank. FoRA selects task-informative layers via a single-pass diagonal Fisher score (under 1% of training cost) and trains the LoRA down-projection at selected layers on the Stiefel manifold, preserving column orthonormality and effective rank. FoRA consistently outperforms LoRA and DoRA at half their parameter budget, and falls within 0.7-0.8 accuracy points of AdaLoRA at one-quarter its parameter count, across five LLaMA-family backbones. Cross-architecture experiments on twelve backbones from the LLaMA, Qwen3, and Gemma families confirm consistent gains from 270M to 32B parameters. The two components combine super-additively: Fisher selection alone matches rank reduction at the same budget, while the Stiefel constraint provides the decisive additional gain.
title FoRA: Fisher-orthogonal Rank Adaptation for Parameter-Efficient Fine-Tuning
topic Computation and Language
url https://arxiv.org/abs/2605.29317