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Main Authors: Wang, Hongyu, Ma, Shuming, Wei, Furu
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2504.18415
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author Wang, Hongyu
Ma, Shuming
Wei, Furu
author_facet Wang, Hongyu
Ma, Shuming
Wei, Furu
contents Efficient deployment of 1-bit Large Language Models (LLMs) is hindered by activation outliers, which complicate quantization to low bit-widths. We introduce BitNet v2, a novel framework enabling native 4-bit activation quantization for 1-bit LLMs. To tackle outliers in attention and feed-forward network activations, we propose H-BitLinear, a module applying an online Hadamard transformation prior to activation quantization. This transformation smooths sharp activation distributions into more Gaussian-like forms, suitable for low-bit representation. Experiments show BitNet v2 trained from scratch with 8-bit activations matches BitNet b1.58 performance. Crucially, BitNet v2 achieves minimal performance degradation when trained with native 4-bit activations, significantly reducing memory footprint and computational cost for batched inference.
format Preprint
id arxiv_https___arxiv_org_abs_2504_18415
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle BitNet v2: Native 4-bit Activations with Hadamard Transformation for 1-bit LLMs
Wang, Hongyu
Ma, Shuming
Wei, Furu
Computation and Language
Machine Learning
Efficient deployment of 1-bit Large Language Models (LLMs) is hindered by activation outliers, which complicate quantization to low bit-widths. We introduce BitNet v2, a novel framework enabling native 4-bit activation quantization for 1-bit LLMs. To tackle outliers in attention and feed-forward network activations, we propose H-BitLinear, a module applying an online Hadamard transformation prior to activation quantization. This transformation smooths sharp activation distributions into more Gaussian-like forms, suitable for low-bit representation. Experiments show BitNet v2 trained from scratch with 8-bit activations matches BitNet b1.58 performance. Crucially, BitNet v2 achieves minimal performance degradation when trained with native 4-bit activations, significantly reducing memory footprint and computational cost for batched inference.
title BitNet v2: Native 4-bit Activations with Hadamard Transformation for 1-bit LLMs
topic Computation and Language
Machine Learning
url https://arxiv.org/abs/2504.18415