자료유형  

 학위논문

Control Number  

0017163770

International Standard Book Number  

9798342125130

Dewey Decimal Classification Number  

500

Main Entry-Personal Name  

Liu, Xinyu.

Publication, Distribution, etc. (Imprint  

[S.l.] : Purdue University., 2024

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2024

Physical Description  

177 p.

General Note  

Source: Dissertations Abstracts International, Volume: 86-04, Section: A.

General Note  

Advisor: Shen, Jie.

Dissertation Note  

Thesis (Ph.D.)--Purdue University, 2024.

Summary, Etc.  

요약This thesis presents advances in numerical methods for partial differential equations (PDEs) and optimization problems, with a focus on improving efficiency, stability, and accuracy across various applications. We begin by addressing 3D Poisson-type equations, developing a GPU-accelerated spectral-element method that utilizes the tensor product structure to achieve extremely fast performance. This approach enables solving problems with over one billion degrees of freedom in less than one second on modern GPUs, with applications to Schrodinger and Cahn-Hilliard equations demonstrated. Next, we focus on parabolic PDEs, specifically the Cahn-Hilliard equation with dynamical boundary conditions. We propose an efficient energy-stable numerical scheme using a unified framework to handle both Allen-Cahn and Cahn-Hilliard type boundary conditions. The scheme employs a scalar auxiliary variable (SAV) approach to achieve linear, second-order, and unconditionally energy stable properties. Shifting to a machine learning perspective for PDEs, we introduce an unsupervised learning-based numerical method for solving elliptic PDEs. This approach uses deep neural networks to approximate PDE solutions and employs least-squares functionals as loss functions, with a focus on first-order system least-squares formulations. In the realm of optimization, we present an efficient and robust SAV based algorithm for discrete gradient systems. This method modifies the standard SAV approach and incorporates relaxation and adaptive strategies to achieve fast convergence for minimization problems while maintaining unconditional energy stability. Finally, we address optimization in the context of machine learning by developing a structure-guided Gauss-Newton method for shallow ReLU neural network optimization. This approach exploits both the least-squares and neural network structures to create an efficient iterative solver, demonstrating superior performance on challenging function approximation problems. Throughout the thesis, we provide theoretical analysis, efficient numerical implementations, and extensive computational experiments to validate the proposed methods.

Subject Added Entry-Topical Term  

Decomposition.

Subject Added Entry-Topical Term  

Partial differential equations.

Subject Added Entry-Topical Term  

Energy.

Subject Added Entry-Topical Term  

Network management systems.

Subject Added Entry-Topical Term  

Boundary conditions.

Subject Added Entry-Topical Term  

Neural networks.

Subject Added Entry-Topical Term  

Information science.

Subject Added Entry-Topical Term  

Mathematics.

Added Entry-Corporate Name  

Purdue University.

Host Item Entry  

Dissertations Abstracts International. 86-04A.

Electronic Location and Access  

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Control Number  

joongbu:657170