Zeroth-Order Fine-Tuning of LLMs in Learnable Low-Rank Subspaces
AdaSub-ZO is a novel forward-only fine-tuning method for large language models that uses learnable low-rank projection matrices to guide gradient directions. It improves standard zeroth-order optimization by learning task-aware perturbations and incorporating subspace momentum to smooth noisy estimates, leading to faster convergence and better performance on LLMs.