DuQuant++: Fine-grained Rotation Enhances Microscaling FP4 Quantization

Fuente: arXiv
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Main Authors: Lin, Haokun, Jia, Xinle, Xu, Haobo, Yao, Bingchen, Guo, Xianglong, Wu, Yichen, Lu, Zhichao, Wei, Ying, Zhang, Qingfu, Sun, Zhenan
Format: Preprint
Published: 2026
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author Lin, Haokun
Jia, Xinle
Xu, Haobo
Yao, Bingchen
Guo, Xianglong
Wu, Yichen
Lu, Zhichao
Wei, Ying
Zhang, Qingfu
Sun, Zhenan
author_facet Lin, Haokun
Jia, Xinle
Xu, Haobo
Yao, Bingchen
Guo, Xianglong
Wu, Yichen
Lu, Zhichao
Wei, Ying
Zhang, Qingfu
Sun, Zhenan
contents The MXFP4 microscaling format, which partitions tensors into blocks of 32 elements sharing an E8M0 scaling factor, has emerged as a promising substrate for efficient LLM inference, backed by native hardware support on NVIDIA Blackwell Tensor Cores. However, activation outliers pose a unique challenge under this format: a single outlier inflates the shared block scale, compressing the effective dynamic range of the remaining elements and causing significant quantization error. Existing rotation-based remedies, including randomized Hadamard and learnable rotations, are data-agnostic and therefore unable to specifically target the channels where outliers concentrate. We propose DuQuant++, which adapts the outlier-aware fine-grained rotation of DuQuant to the MXFP4 format by aligning the rotation block size with the microscaling group size (B{=}32). Because each MXFP4 group possesses an independent scaling factor, the cross-block variance issue that necessitates dual rotations and a zigzag permutation in the original DuQuant becomes irrelevant, enabling DuQuant++ to replace the entire pipeline with a single outlier-aware rotation, which halves the online rotation cost while simultaneously smoothing the weight distribution. Extensive experiments on the LLaMA-3 family under MXFP4 W4A4 quantization show that DuQuant++ consistently achieves state-of-the-art performance. Our code is available at https://github.com/Hsu1023/DuQuant-v2.
format Preprint
id arxiv_https___arxiv_org_abs_2604_17789
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle DuQuant++: Fine-grained Rotation Enhances Microscaling FP4 Quantization
Lin, Haokun
Jia, Xinle
Xu, Haobo
Yao, Bingchen
Guo, Xianglong
Wu, Yichen
Lu, Zhichao
Wei, Ying
Zhang, Qingfu
Sun, Zhenan
Computer Vision and Pattern Recognition
Artificial Intelligence
Computation and Language
The MXFP4 microscaling format, which partitions tensors into blocks of 32 elements sharing an E8M0 scaling factor, has emerged as a promising substrate for efficient LLM inference, backed by native hardware support on NVIDIA Blackwell Tensor Cores. However, activation outliers pose a unique challenge under this format: a single outlier inflates the shared block scale, compressing the effective dynamic range of the remaining elements and causing significant quantization error. Existing rotation-based remedies, including randomized Hadamard and learnable rotations, are data-agnostic and therefore unable to specifically target the channels where outliers concentrate. We propose DuQuant++, which adapts the outlier-aware fine-grained rotation of DuQuant to the MXFP4 format by aligning the rotation block size with the microscaling group size (B{=}32). Because each MXFP4 group possesses an independent scaling factor, the cross-block variance issue that necessitates dual rotations and a zigzag permutation in the original DuQuant becomes irrelevant, enabling DuQuant++ to replace the entire pipeline with a single outlier-aware rotation, which halves the online rotation cost while simultaneously smoothing the weight distribution. Extensive experiments on the LLaMA-3 family under MXFP4 W4A4 quantization show that DuQuant++ consistently achieves state-of-the-art performance. Our code is available at https://github.com/Hsu1023/DuQuant-v2.
title DuQuant++: Fine-grained Rotation Enhances Microscaling FP4 Quantization
topic Computer Vision and Pattern Recognition
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2604.17789