Search Results for author: Lichen Zhang

Found 10 papers, 0 papers with code

Solving Attention Kernel Regression Problem via Pre-conditioner

no code implementations28 Aug 2023 Zhao Song, Junze Yin, Lichen Zhang

Given an input matrix $A\in \mathbb{R}^{n\times d}$ with $n\gg d$ and a response vector $b$, we first consider the matrix exponential of the matrix $A^\top A$ as a proxy, and we in turn design algorithms for two types of regression problems: $\min_{x\in \mathbb{R}^d}\|(A^\top A)^jx-b\|_2$ and $\min_{x\in \mathbb{R}^d}\|A(A^\top A)^jx-b\|_2$ for any positive integer $j$.

regression

Faster Algorithms for Structured Linear and Kernel Support Vector Machines

no code implementations15 Jul 2023 Yuzhou Gu, Zhao Song, Lichen Zhang

Consequently, we obtain a variety of results for SVMs: * For linear SVM, where the quadratic constraint matrix has treewidth $\tau$, we can solve the corresponding program in time $\widetilde O(n\tau^{(\omega+1)/2}\log(1/\epsilon))$; * For linear SVM, where the quadratic constraint matrix admits a low-rank factorization of rank-$k$, we can solve the corresponding program in time $\widetilde O(nk^{(\omega+1)/2}\log(1/\epsilon))$; * For Gaussian kernel SVM, where the data dimension $d = \Theta(\log n)$ and the squared dataset radius is small, we can solve it in time $O(n^{1+o(1)}\log(1/\epsilon))$.

Efficient Alternating Minimization with Applications to Weighted Low Rank Approximation

no code implementations7 Jun 2023 Zhao Song, Mingquan Ye, Junze Yin, Lichen Zhang

For weighted low rank approximation, this improves the runtime of [LLR16] from $n^2 k^2$ to $n^2k$.

2k

Low Rank Matrix Completion via Robust Alternating Minimization in Nearly Linear Time

no code implementations21 Feb 2023 Yuzhou Gu, Zhao Song, Junze Yin, Lichen Zhang

Moreover, our algorithm runs in time $\widetilde O(|\Omega| k)$, which is nearly linear in the time to verify the solution while preserving the sample complexity.

Low-Rank Matrix Completion regression

A Nearly-Optimal Bound for Fast Regression with $\ell_\infty$ Guarantee

no code implementations1 Feb 2023 Zhao Song, Mingquan Ye, Junze Yin, Lichen Zhang

One popular approach for solving such $\ell_2$ regression problem is via sketching: picking a structured random matrix $S\in \mathbb{R}^{m\times n}$ with $m\ll n$ and $SA$ can be quickly computed, solve the ``sketched'' regression problem $\arg\min_{x\in \mathbb{R}^d} \|SAx-Sb\|_2$.

regression

Sketching for First Order Method: Efficient Algorithm for Low-Bandwidth Channel and Vulnerability

no code implementations15 Oct 2022 Zhao Song, Yitan Wang, Zheng Yu, Lichen Zhang

In this paper, we propose a novel sketching scheme for the first order method in large-scale distributed learning setting, such that the communication costs between distributed agents are saved while the convergence of the algorithms is still guaranteed.

Federated Learning

Dynamic Tensor Product Regression

no code implementations8 Oct 2022 Aravind Reddy, Zhao Song, Lichen Zhang

In this work, we initiate the study of \emph{Dynamic Tensor Product Regression}.

regression

Training Multi-Layer Over-Parametrized Neural Network in Subquadratic Time

no code implementations14 Dec 2021 Zhao Song, Lichen Zhang, Ruizhe Zhang

We consider the problem of training a multi-layer over-parametrized neural network to minimize the empirical risk induced by a loss function.

Iterative Sketching and its Application to Federated Learning

no code implementations29 Sep 2021 Zhao Song, Zheng Yu, Lichen Zhang

Though most federated learning frameworks only require clients and the server to send gradient information over the network, they still face the challenges of communication efficiency and data privacy.

Federated Learning LEMMA

Fast Sketching of Polynomial Kernels of Polynomial Degree

no code implementations21 Aug 2021 Zhao Song, David P. Woodruff, Zheng Yu, Lichen Zhang

Recent techniques in oblivious sketching reduce the dependence in the running time on the degree $q$ of the polynomial kernel from exponential to polynomial, which is useful for the Gaussian kernel, for which $q$ can be chosen to be polylogarithmic.

BIG-bench Machine Learning

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