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Negative / Null Result ReportOpen accessComputer Science

Not How Many, But Which: Parameter Placement in Low-Rank Adaptation

Arijit Sehanobish; Charles Lovering · 2026 · arXiv

WASTE classifies this as Negative / Null Result Report · AI classification, approximate

The study found no significant effect — useful as a negative control or null benchmark for your own design.

Abstract (excerpt)

We study the \textit{parameter placement problem}: given a fixed budget of $k$ trainable entries within the B matrix of a LoRA adapter (A frozen), does the choice of which $k$ matter? Under supervised fine-tuning, random and informed subsets achieve comparable performance. Under GRPO on base models, random placement fails to improve over the base model, while gradient-informed placement recovers standard LoRA accuracy. This regime dependence traces to gradient structure: SFT gradients are low-rank and directionally stable, so any subset accumulates coherent updates; GRPO gradients are high-ran

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Metadata source: arXiv