Search Results for author: Qiuwei Li

Found 10 papers, 4 papers with code

A Provable Splitting Approach for Symmetric Nonnegative Matrix Factorization

no code implementations25 Jan 2023 Xiao Li, Zhihui Zhu, Qiuwei Li, Kai Liu

The symmetric Nonnegative Matrix Factorization (NMF), a special but important class of the general NMF, has found numerous applications in data analysis such as various clustering tasks.

Clustering Image Clustering +1

JFB: Jacobian-Free Backpropagation for Implicit Networks

2 code implementations23 Mar 2021 Samy Wu Fung, Howard Heaton, Qiuwei Li, Daniel Mckenzie, Stanley Osher, Wotao Yin

Unlike traditional networks, implicit networks solve a fixed point equation to compute inferences.

Distributed Low-rank Matrix Factorization With Exact Consensus

1 code implementation NeurIPS 2019 Zhihui Zhu, Qiuwei Li, Xinshuo Yang, Gongguo Tang, Michael B. Wakin

Low-rank matrix factorization is a problem of broad importance, owing to the ubiquity of low-rank models in machine learning contexts.

Provable Bregman-divergence based Methods for Nonconvex and Non-Lipschitz Problems

no code implementations22 Apr 2019 Qiuwei Li, Zhihui Zhu, Gongguo Tang, Michael B. Wakin

Therefore, this work not only develops guaranteed optimization methods for non-Lipschitz smooth problems but also solves an open problem of showing the second-order convergence guarantees for these alternating minimization methods.

Spherical Principal Component Analysis

1 code implementation16 Mar 2019 Kai Liu, Qiuwei Li, Hua Wang, Gongguo Tang

However, most of the studies on PCA aim to minimize the loss after projection, which usually measures the Euclidean distance, though in some fields, angle distance is known to be more important and critical for analysis.

Clustering

Dropping Symmetry for Fast Symmetric Nonnegative Matrix Factorization

no code implementations NeurIPS 2018 Zhihui Zhu, Xiao Li, Kai Liu, Qiuwei Li

Symmetric nonnegative matrix factorization (NMF), a special but important class of the general NMF, is demonstrated to be useful for data analysis and in particular for various clustering tasks.

Clustering Image Clustering

Global Optimality in Distributed Low-rank Matrix Factorization

no code implementations7 Nov 2018 Zhihui Zhu, Qiuwei Li, Xinshuo Yang, Gongguo Tang, Michael B. Wakin

We study the convergence of a variant of distributed gradient descent (DGD) on a distributed low-rank matrix approximation problem wherein some optimization variables are used for consensus (as in classical DGD) and some optimization variables appear only locally at a single node in the network.

Optimized Structured Sparse Sensing Matrices for Compressive Sensing

no code implementations19 Sep 2017 Tao Hong, Xiao Li, Zhihui Zhu, Qiuwei Li

We consider designing a robust structured sparse sensing matrix consisting of a sparse matrix with a few non-zero entries per row and a dense base matrix for capturing signals efficiently We design the robust structured sparse sensing matrix through minimizing the distance between the Gram matrix of the equivalent dictionary and the target Gram of matrix holding small mutual coherence.

Compressive Sensing Image Compression

Geometry of Factored Nuclear Norm Regularization

no code implementations5 Apr 2017 Qiuwei Li, Zhihui Zhu, Gongguo Tang

In spite of the nonconvexity of the factored formulation, we prove that when the convex loss function $f(X)$ is $(2r, 4r)$-restricted well-conditioned, each critical point of the factored problem either corresponds to the optimal solution $X^\star$ of the original convex optimization or is a strict saddle point where the Hessian matrix has a strictly negative eigenvalue.

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