Jonas M. Kübler
2025
Wanda++: Pruning Large Language Models via Regional Gradients
Yifan Yang
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Kai Zhen
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Bhavana Ganesh
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Aram Galstyan
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Goeric Huybrechts
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Markus Müller
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Jonas M. Kübler
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Rupak Vignesh Swaminathan
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Athanasios Mouchtaris
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Sravan Babu Bodapati
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Nathan Susanj
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Zheng Zhang
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Jack FitzGerald
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Abhishek Kumar
Findings of the Association for Computational Linguistics: ACL 2025
Large Language Models (LLMs) pruning seeks to remove unimportant weights for inference speedup with minimal accuracy impact. However, existing methods often suffer from accuracy degradation without full-model sparsity-aware fine-tuning. This paper presents Wanda++, a novel pruning framework that outperforms the state-of-the-art methods by utilizing decoder-block-level regional gradients. Specifically, Wanda++ improves the pruning score with regional gradients for the first time and proposes an efficient regional optimization method to minimize pruning-induced output discrepancies between the dense and sparse decoder output. Notably, Wanda++ improves perplexity by up to 32% over Wanda in the language modeling task and generalizes effectively to downstream tasks. Moreover, despite updating weights with regional optimization, Wanda++ remains orthogonal to sparsity-aware fine-tuning, further reducing perplexity with LoRA in great extend. Our approach is lightweight, pruning a 7B LLaMA model in under 10 minutes on a single H100 GPU.