HD-PiSSA: High-Rank Distributed Orthogonal Adaptation

Fuente: arXiv
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Main Authors: Wang, Yiding, Meng, Fauxu, Zhang, Xuefeng, Jiang, Fan, Tang, Pingzhi, Zhang, Muhan
Format: Preprint
Published: 2025
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author Wang, Yiding
Meng, Fauxu
Zhang, Xuefeng
Jiang, Fan
Tang, Pingzhi
Zhang, Muhan
author_facet Wang, Yiding
Meng, Fauxu
Zhang, Xuefeng
Jiang, Fan
Tang, Pingzhi
Zhang, Muhan
contents Existing parameter-efficient fine-tuning (PEFT) methods for large language models (LLMs), such as LoRA and PiSSA, constrain model updates to low-rank subspaces, limiting their expressiveness and leading to suboptimal performance on complex tasks. To address this, we introduce High-rank Distributed PiSSA (HD-PiSSA), a distributed PEFT approach that initializes orthogonal adapters across different devices and aggregates their delta updates collectively on W for fine-tuning. Unlike Data Parallel LoRA or PiSSA, which maintain identical adapters across all devices, HD-PiSSA assigns different principal components of the pre-trained weights to each GPU, significantly expanding the range of update directions. This results in over 16x higher effective updated ranks than data-parallel LoRA or PiSSA when fine-tuning on 8 GPUs with the same per-device adapter rank. Empirically, we evaluate HD-PiSSA across various challenging downstream tasks, including mathematics, code generation, and multi-task learning. In the multi-task setting, HD-PiSSA achieves average gains of 10.0 absolute points (14.63%) over LoRA and 4.98 points (6.60%) over PiSSA across 12 benchmarks, demonstrating its benefits from the extra optimization flexibility.
format Preprint
id arxiv_https___arxiv_org_abs_2505_18777
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle HD-PiSSA: High-Rank Distributed Orthogonal Adaptation
Wang, Yiding
Meng, Fauxu
Zhang, Xuefeng
Jiang, Fan
Tang, Pingzhi
Zhang, Muhan
Machine Learning
Artificial Intelligence
Existing parameter-efficient fine-tuning (PEFT) methods for large language models (LLMs), such as LoRA and PiSSA, constrain model updates to low-rank subspaces, limiting their expressiveness and leading to suboptimal performance on complex tasks. To address this, we introduce High-rank Distributed PiSSA (HD-PiSSA), a distributed PEFT approach that initializes orthogonal adapters across different devices and aggregates their delta updates collectively on W for fine-tuning. Unlike Data Parallel LoRA or PiSSA, which maintain identical adapters across all devices, HD-PiSSA assigns different principal components of the pre-trained weights to each GPU, significantly expanding the range of update directions. This results in over 16x higher effective updated ranks than data-parallel LoRA or PiSSA when fine-tuning on 8 GPUs with the same per-device adapter rank. Empirically, we evaluate HD-PiSSA across various challenging downstream tasks, including mathematics, code generation, and multi-task learning. In the multi-task setting, HD-PiSSA achieves average gains of 10.0 absolute points (14.63%) over LoRA and 4.98 points (6.60%) over PiSSA across 12 benchmarks, demonstrating its benefits from the extra optimization flexibility.
title HD-PiSSA: High-Rank Distributed Orthogonal Adaptation
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2505.18777