Papers › Towards Understanding Mixture of Experts in Deep Learning

Towards Understanding Mixture of Experts in Deep Learning

4 Aug 2022arXiv:2208.02813archive 2025-07-28

Zixiang Chen, Yihe Deng, Yue Wu, Quanquan Gu, Yuanzhi Li

The Mixture-of-Experts (MoE) layer, a sparsely-activated model controlled by a router, has achieved great success in deep learning. However, the understanding of such architecture remains elusive. In this paper, we formally study how the MoE layer improves the performance of neural network learning and why the mixture model will not collapse into a single model. Our empirical results suggest that the cluster structure of the underlying problem and the non-linearity of the expert are pivotal to the success of MoE. To further understand this, we consider a challenging classification problem with intrinsic cluster structures, which is hard to learn using a single expert. Yet with the MoE layer, by choosing the experts as two-layer nonlinear convolutional neural networks (CNNs), we show that the problem can be learned successfully. Furthermore, our theory shows that the router can learn the cluster-center features, which helps divide the input complex problem into simpler linear classification sub-problems that individual experts can conquer. To our knowledge, this is the first result towards formally understanding the mechanism of the MoE layer for deep learning.

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uclaml/MoE officialpytorchApache-2.0 report
agwaBom/towards_moe mentioned on GitHubpytorchMIT report

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format_time uclaml/MoE/cifar10-rotate/utils.py official repository ran · our draft was wrong fingerprinted Apache-2.0 (permissive) · 8d7ec010c29e813b · report
top1 uclaml/MoE/cifar10-rotate/moe.py official repository ran · our draft was wrong fingerprinted Apache-2.0 (permissive) · 213bf6a36ff4baa6 · report
choose1 uclaml/MoE/cifar10-rotate/moe.py official repository unverified Apache-2.0 (permissive) · c22b66765b1273dc · report
choose2 uclaml/MoE/cifar10-rotate/moe.py official repository unverified Apache-2.0 (permissive) · 821323ceb5b0974e · report
entropy uclaml/MoE/cifar10-rotate/utils.py official repository unverified Apache-2.0 (permissive) · 470b52f8557d6cc9 · report
preprocess uclaml/MoE/linguistic/data.py official repository unverified Apache-2.0 (permissive) · e1fad8bbeeffe026 · report

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Deep LearningMixture-of-Experts

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