Advancing the Understanding of Fixed Point Iterations in Deep Neural Networks: A Detailed Analytical Study

Fuente: arXiv
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Autori principali: Ke, Yekun, Li, Xiaoyu, Liang, Yingyu, Shi, Zhenmei, Song, Zhao
Natura: Preprint
Pubblicazione: 2024
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author Ke, Yekun
Li, Xiaoyu
Liang, Yingyu
Shi, Zhenmei
Song, Zhao
author_facet Ke, Yekun
Li, Xiaoyu
Liang, Yingyu
Shi, Zhenmei
Song, Zhao
contents Recent empirical studies have identified fixed point iteration phenomena in deep neural networks, where the hidden state tends to stabilize after several layers, showing minimal change in subsequent layers. This observation has spurred the development of practical methodologies, such as accelerating inference by bypassing certain layers once the hidden state stabilizes, selectively fine-tuning layers to modify the iteration process, and implementing loops of specific layers to maintain fixed point iterations. Despite these advancements, the understanding of fixed point iterations remains superficial, particularly in high-dimensional spaces, due to the inadequacy of current analytical tools. In this study, we conduct a detailed analysis of fixed point iterations in a vector-valued function modeled by neural networks. We establish a sufficient condition for the existence of multiple fixed points of looped neural networks based on varying input regions. Additionally, we expand our examination to include a robust version of fixed point iterations. To demonstrate the effectiveness and insights provided by our approach, we provide case studies that looped neural networks may exist $2^d$ number of robust fixed points under exponentiation or polynomial activation functions, where $d$ is the feature dimension. Furthermore, our preliminary empirical results support our theoretical findings. Our methodology enriches the toolkit available for analyzing fixed point iterations of deep neural networks and may enhance our comprehension of neural network mechanisms.
format Preprint
id arxiv_https___arxiv_org_abs_2410_11279
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Advancing the Understanding of Fixed Point Iterations in Deep Neural Networks: A Detailed Analytical Study
Ke, Yekun
Li, Xiaoyu
Liang, Yingyu
Shi, Zhenmei
Song, Zhao
Machine Learning
Artificial Intelligence
Numerical Analysis
Recent empirical studies have identified fixed point iteration phenomena in deep neural networks, where the hidden state tends to stabilize after several layers, showing minimal change in subsequent layers. This observation has spurred the development of practical methodologies, such as accelerating inference by bypassing certain layers once the hidden state stabilizes, selectively fine-tuning layers to modify the iteration process, and implementing loops of specific layers to maintain fixed point iterations. Despite these advancements, the understanding of fixed point iterations remains superficial, particularly in high-dimensional spaces, due to the inadequacy of current analytical tools. In this study, we conduct a detailed analysis of fixed point iterations in a vector-valued function modeled by neural networks. We establish a sufficient condition for the existence of multiple fixed points of looped neural networks based on varying input regions. Additionally, we expand our examination to include a robust version of fixed point iterations. To demonstrate the effectiveness and insights provided by our approach, we provide case studies that looped neural networks may exist $2^d$ number of robust fixed points under exponentiation or polynomial activation functions, where $d$ is the feature dimension. Furthermore, our preliminary empirical results support our theoretical findings. Our methodology enriches the toolkit available for analyzing fixed point iterations of deep neural networks and may enhance our comprehension of neural network mechanisms.
title Advancing the Understanding of Fixed Point Iterations in Deep Neural Networks: A Detailed Analytical Study
topic Machine Learning
Artificial Intelligence
Numerical Analysis
url https://arxiv.org/abs/2410.11279