Learning Grouped Lattice Vector Quantizers for Low-Bit LLM Compression

Fuente: arXiv
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Autori principali: Zhang, Xi, Wu, Xiaolin, Wang, Jiamang, Lin, Weisi
Natura: Preprint
Pubblicazione: 2025
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author Zhang, Xi
Wu, Xiaolin
Wang, Jiamang
Lin, Weisi
author_facet Zhang, Xi
Wu, Xiaolin
Wang, Jiamang
Lin, Weisi
contents Large Language Models (LLMs) have demonstrated remarkable capabilities but typically require extensive computational resources and memory for inference. Post-training quantization (PTQ) can effectively reduce these demands by storing weights in lower bit-width formats. However, standard uniform quantization often leads to notable performance degradation, particularly in low-bit scenarios. In this work, we introduce a Grouped Lattice Vector Quantization (GLVQ) framework that assigns each group of weights a customized lattice codebook, defined by a learnable generation matrix. To address the non-differentiability of the quantization process, we adopt Babai rounding to approximate nearest-lattice-point search during training, which enables stable optimization of the generation matrices. Once trained, decoding reduces to a simple matrix-vector multiplication, yielding an efficient and practical quantization pipeline. Experiments on multiple benchmarks show that our approach achieves a better trade-off between model size and accuracy compared to existing post-training quantization baselines, highlighting its effectiveness in deploying large models under stringent resource constraints. Our source code is available on GitHub repository: https://github.com/xzhang9308/GLVQ.
format Preprint
id arxiv_https___arxiv_org_abs_2510_20984
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Learning Grouped Lattice Vector Quantizers for Low-Bit LLM Compression
Zhang, Xi
Wu, Xiaolin
Wang, Jiamang
Lin, Weisi
Machine Learning
Artificial Intelligence
Large Language Models (LLMs) have demonstrated remarkable capabilities but typically require extensive computational resources and memory for inference. Post-training quantization (PTQ) can effectively reduce these demands by storing weights in lower bit-width formats. However, standard uniform quantization often leads to notable performance degradation, particularly in low-bit scenarios. In this work, we introduce a Grouped Lattice Vector Quantization (GLVQ) framework that assigns each group of weights a customized lattice codebook, defined by a learnable generation matrix. To address the non-differentiability of the quantization process, we adopt Babai rounding to approximate nearest-lattice-point search during training, which enables stable optimization of the generation matrices. Once trained, decoding reduces to a simple matrix-vector multiplication, yielding an efficient and practical quantization pipeline. Experiments on multiple benchmarks show that our approach achieves a better trade-off between model size and accuracy compared to existing post-training quantization baselines, highlighting its effectiveness in deploying large models under stringent resource constraints. Our source code is available on GitHub repository: https://github.com/xzhang9308/GLVQ.
title Learning Grouped Lattice Vector Quantizers for Low-Bit LLM Compression
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2510.20984