Piecewise Strong Convexity of Neural Networks
We study the loss surface of a feed-forward neural network with ReLU non-linearities, regularized with weight decay. We show that the regularized loss function is piecewise strongly convex on an important open set which contains, under some conditions, all of its global minimizers. This is used to prove that local minima of the regularized loss function in this set are isolated, and that every differentiable critical point in this set is a local minimum, partially addressing an open problem given at the Conference on Learning Theory (COLT) 2015; our result is also applied to linear neural networks to show that with weight decay regularization, there are no non-zero critical points in a norm ball obtaining training error below a given threshold. We also include an experimental section where we validate our theoretical work and show that the regularized loss function is almost always piecewise strongly convex when restricted to stochastic gradient descent trajectories for three standard image classification problems.
Code (0)
등록된 구현이 없습니다.
Tasks
image-classificationImage ClassificationLearning TheoryMethods 이 논문이 사용한 방법론
Similar Papers 제목 키워드 기반
Piecewise convexity of artificial neural networks
Although artificial neural networks have shown great promise in applications including computer vision and speech recognition, there remains considerable practical and theoretical difficulty in optimizing their parameter…
global-optimizationspeech-recognitionSpeech RecognitionPerfect reconstruction of sparse signals with piecewise continuous nonconvex penalties and nonconvexity control
We consider compressed sensing formulated as a minimization problem of nonconvex sparse penalties, Smoothly Clipped Absolute deviation (SCAD) and Minimax Concave Penalty (MCP). The nonconvexity of these penalties is cont…
compressed sensingPiecewise Convex Function Estimation and Model Selection
Given noisy data, function estimation is considered when the unknown function is known apriori to consist of a small number of regions where the function is either convex or concave. When the regions are known apriori, t…
modelModel SelectionStrong convexity-guided hyper-parameter optimization for flatter losses
We propose a novel white-box approach to hyper-parameter optimization. Motivated by recent work establishing a relationship between flat minima and generalization, we first establish a relationship between the strong con…
Fast networked data selection via distributed smoothed quantile estimation
Collecting the most informative data from a large dataset distributed over a network is a fundamental problem in many fields, including control, signal processing and machine learning. In this paper, we establish a conne…