Search Results for author: Zhenyu Liao

Found 24 papers, 7 papers with code

Semantic Image Manipulation with Background-guided Internal Learning

no code implementations24 Mar 2022 Zhongping Zhang, Huiwen He, Bryan A. Plummer, Zhenyu Liao, Huayan Wang

We outperform the state-of-the-art in a quantitative and qualitative evaluation on the CLEVR and Visual Genome datasets.

Image Inpainting Image Manipulation

Fine-Grained Control of Artistic Styles in Image Generation

no code implementations19 Oct 2021 Xin Miao, Huayan Wang, Jun Fu, Jiayi Liu, Shen Wang, Zhenyu Liao

The style vectors are fed to the generator and discriminator to achieve fine-grained control.

Image Generation

Random matrices in service of ML footprint: ternary random features with no performance loss

1 code implementation ICLR 2022 Hafiz Tiomoko Ali, Zhenyu Liao, Romain Couillet

As a result, for any kernel matrix ${\bf K}$ of the form above, we propose a novel random features technique, called Ternary Random Feature (TRF), that (i) asymptotically yields the same limiting kernel as the original ${\bf K}$ in a spectral sense and (ii) can be computed and stored much more efficiently, by wisely tuning (in a data-dependent manner) the function $\sigma$ and the random vector ${\bf w}$, both taking values in $\{-1, 0, 1\}$.


Hessian Eigenspectra of More Realistic Nonlinear Models

no code implementations NeurIPS 2021 Zhenyu Liao, Michael W. Mahoney

Given an optimization problem, the Hessian matrix and its eigenspectrum can be used in many ways, ranging from designing more efficient second-order algorithms to performing model analysis and regression diagnostics.

Sparse sketches with small inversion bias

no code implementations21 Nov 2020 Michał Dereziński, Zhenyu Liao, Edgar Dobriban, Michael W. Mahoney

For a tall $n\times d$ matrix $A$ and a random $m\times n$ sketching matrix $S$, the sketched estimate of the inverse covariance matrix $(A^\top A)^{-1}$ is typically biased: $E[(\tilde A^\top\tilde A)^{-1}]\ne(A^\top A)^{-1}$, where $\tilde A=SA$.

Distributed Optimization

Kernel regression in high dimensions: Refined analysis beyond double descent

no code implementations6 Oct 2020 Fanghui Liu, Zhenyu Liao, Johan A. K. Suykens

In this paper, we provide a precise characterization of generalization properties of high dimensional kernel ridge regression across the under- and over-parameterized regimes, depending on whether the number of training data n exceeds the feature dimension d. By establishing a bias-variance decomposition of the expected excess risk, we show that, while the bias is (almost) independent of d and monotonically decreases with n, the variance depends on n, d and can be unimodal or monotonically decreasing under different regularization schemes.


Sparse Quantized Spectral Clustering

no code implementations ICLR 2021 Zhenyu Liao, Romain Couillet, Michael W. Mahoney

Given a large data matrix, sparsifying, quantizing, and/or performing other entry-wise nonlinear operations can have numerous benefits, ranging from speeding up iterative algorithms for core numerical linear algebra problems to providing nonlinear filters to design state-of-the-art neural network models.


A Random Matrix Analysis of Random Fourier Features: Beyond the Gaussian Kernel, a Precise Phase Transition, and the Corresponding Double Descent

no code implementations NeurIPS 2020 Zhenyu Liao, Romain Couillet, Michael W. Mahoney

This article characterizes the exact asymptotics of random Fourier feature (RFF) regression, in the realistic setting where the number of data samples $n$, their dimension $p$, and the dimension of feature space $N$ are all large and comparable.


Towards Efficient Training for Neural Network Quantization

3 code implementations21 Dec 2019 Qing Jin, Linjie Yang, Zhenyu Liao

To deal with this problem, we propose a simple yet effective technique, named scale-adjusted training (SAT), to comply with the discovered rules and facilitates efficient training.


AdaBits: Neural Network Quantization with Adaptive Bit-Widths

1 code implementation CVPR 2020 Qing Jin, Linjie Yang, Zhenyu Liao

With our proposed techniques applied on a bunch of models including MobileNet-V1/V2 and ResNet-50, we demonstrate that bit-width of weights and activations is a new option for adaptively executable deep neural networks, offering a distinct opportunity for improved accuracy-efficiency trade-off as well as instant adaptation according to the platform constraints in real-world applications.


Rethinking Neural Network Quantization

no code implementations25 Sep 2019 Qing Jin, Linjie Yang, Zhenyu Liao

To deal with this problem, we propose a simple yet effective technique, named scale-adjusted training (SAT), to comply with the discovered rules and facilitates efficient training.


Inner-product Kernels are Asymptotically Equivalent to Binary Discrete Kernels

no code implementations15 Sep 2019 Zhenyu Liao, Romain Couillet

This article investigates the eigenspectrum of the inner product-type kernel matrix $\sqrt{p} \mathbf{K}=\{f( \mathbf{x}_i^{\sf T} \mathbf{x}_j/\sqrt{p})\}_{i, j=1}^n $ under a binary mixture model in the high dimensional regime where the number of data $n$ and their dimension $p$ are both large and comparable.

Complete Dictionary Learning via $\ell^4$-Norm Maximization over the Orthogonal Group

no code implementations6 Jun 2019 Yuexiang Zhai, Zitong Yang, Zhenyu Liao, John Wright, Yi Ma

Most existing methods solve the dictionary (and sparse representations) based on heuristic algorithms, usually without theoretical guarantees for either optimality or complexity.

Dictionary Learning

High Dimensional Classification via Regularized and Unregularized Empirical Risk Minimization: Precise Error and Optimal Loss

no code implementations31 May 2019 Xiaoyi Mai, Zhenyu Liao

Building upon this quantitative error analysis, we identify the simple square loss as the optimal choice for high dimensional classification in both ridge-regularized and unregularized cases, regardless of the number of training samples.

Classification General Classification

Regional Homogeneity: Towards Learning Transferable Universal Adversarial Perturbations Against Defenses

1 code implementation ECCV 2020 Yingwei Li, Song Bai, Cihang Xie, Zhenyu Liao, Xiaohui Shen, Alan L. Yuille

We observe the property of regional homogeneity in adversarial perturbations and suggest that the defenses are less robust to regionally homogeneous perturbations.

object-detection Object Detection +1

A Geometric Approach of Gradient Descent Algorithms in Linear Neural Networks

no code implementations8 Nov 2018 Yacine Chitour, Zhenyu Liao, Romain Couillet

We translate a well-known empirical observation of linear neural nets into a conjecture that we call the \emph{overfitting conjecture} which states that, for almost all training data and initial conditions, the trajectory of the corresponding gradient descent system converges to a global minimum.

On the Spectrum of Random Features Maps of High Dimensional Data

1 code implementation ICML 2018 Zhenyu Liao, Romain Couillet

Random feature maps are ubiquitous in modern statistical machine learning, where they generalize random projections by means of powerful, yet often difficult to analyze nonlinear operators.

BIG-bench Machine Learning

The Dynamics of Learning: A Random Matrix Approach

no code implementations ICML 2018 Zhenyu Liao, Romain Couillet

Understanding the learning dynamics of neural networks is one of the key issues for the improvement of optimization algorithms as well as for the theoretical comprehension of why deep neural nets work so well today.

General Classification

A Random Matrix Approach to Neural Networks

1 code implementation17 Feb 2017 Cosme Louart, Zhenyu Liao, Romain Couillet

This article studies the Gram random matrix model $G=\frac1T\Sigma^{\rm T}\Sigma$, $\Sigma=\sigma(WX)$, classically found in the analysis of random feature maps and random neural networks, where $X=[x_1,\ldots, x_T]\in{\mathbb R}^{p\times T}$ is a (data) matrix of bounded norm, $W\in{\mathbb R}^{n\times p}$ is a matrix of independent zero-mean unit variance entries, and $\sigma:{\mathbb R}\to{\mathbb R}$ is a Lipschitz continuous (activation) function --- $\sigma(WX)$ being understood entry-wise.

A Large Dimensional Analysis of Least Squares Support Vector Machines

1 code implementation11 Jan 2017 Zhenyu Liao, Romain Couillet

In this article, a large dimensional performance analysis of kernel least squares support vector machines (LS-SVMs) is provided under the assumption of a two-class Gaussian mixture model for the input data.

Random matrices meet machine learning: a large dimensional analysis of LS-SVM

no code implementations7 Sep 2016 Zhenyu Liao, Romain Couillet

This article proposes a performance analysis of kernel least squares support vector machines (LS-SVMs) based on a random matrix approach, in the regime where both the dimension of data $p$ and their number $n$ grow large at the same rate.

BIG-bench Machine Learning

Spectral Sparsification and Regret Minimization Beyond Matrix Multiplicative Updates

no code implementations16 Jun 2015 Zeyuan Allen-Zhu, Zhenyu Liao, Lorenzo Orecchia

In this paper, we provide a novel construction of the linear-sized spectral sparsifiers of Batson, Spielman and Srivastava [BSS14].

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