Exploration: fine-tuning with parameter decomposition

TL;DR: We can destroy a 67M-parameter language model's ability to predict German text by fine-tuning a single number: the scalar prefactor on one German-related rank-1 parameter subcomponent. This is an early exploration into using parameter decomposition for a more targeted and interpretable form of model fine-tuning. At small German-token budgets, fine-tuning the scalar prefactor of a single German-related parameter subcomponent beats rank-1 and rank-4 LoRA [1] fine-tunes on the trade-off betw...